WO2022239633A1

WO2022239633A1 - Complex, method for producing same, and shape memory member containing same

Info

Publication number: WO2022239633A1
Application number: PCT/JP2022/018807
Authority: WO
Inventors: 甲一郎宇都; 充宏荏原; 明彦菊池
Original assignee: 国立研究開発法人物質・材料研究機構; 学校法人東京理科大学
Priority date: 2021-05-08
Filing date: 2022-04-26
Publication date: 2022-11-17
Also published as: JPWO2022239633A1

Abstract

The present invention provides a complex which can be used for a shape memory member that can be driven by local heating by means of the application of an electric current. A complex according to one embodiment of the present invention comprises: a crosslinked polymer that has an endothermic peak when the crosslinked polymer is subjected to differential scanning calorimetry (DSC); and a metal nanowire. The complex has electroconductivity at such a level that the electrical resistance of the complex can be measured in an electroconductivity test in at least a state where the complex is not deformed and a state where the complex is deformed at a scale of 100% or more by applying a stress to the complex in a specific direction from the outside of the complex, and the detachment of the metal nanowire does not substantially occur in a stability test using a good solvent for the crosslinked polymer and/or the metal nanowire.

Description

COMPOSITE, MANUFACTURING METHOD THEREOF, AND SHAPE MEMORY MEMBER CONTAINING THE SAME

The present invention relates to a composite, a manufacturing method thereof, and a shape memory member including the same.

Aliphatic polyester resins such as polycaprolactone are known to have excellent biodegradability, and research is underway. Non-Patent Document 1 describes a temperature-responsive poly(ε-caprolactone) membrane.

The film described in Non-Patent Document 1 memorizes the applied deformation, and when heated to a predetermined temperature (this temperature is hereinafter also referred to as "driving temperature"), it returns to the shape before the deformation is applied. It had shape memory ability. However, in order to exert the shape memory ability, it is necessary to heat the membrane and/or the surrounding environment of the membrane. , there is room for improvement in terms of adverse effects on surrounding tissues due to heating.

Accordingly, an object of the present invention is to provide a composite that can be applied to a shape memory member that can be driven by local heating by applying an electric current.
Another object of the present invention is to provide a method for manufacturing such a composite, and a shape memory member including the composite.

As a result of intensive studies aimed at achieving the above problems, the inventors found that the above problems can be achieved with the following configuration.

[1] A composite comprising a crosslinked polymer having an endothermic peak when differential scanning calorimetry (DSC) is performed, and a metal nanowire, in a conductive test, at least before deformation state, and in a state of being deformed by 100% or more in a predetermined direction by applying stress from the outside, having conductivity to the extent that electrical resistance can be measured, and the crosslinked polymer and / or the metal nanowire A composite that does not substantially cause detachment of the metal nanowires in a stability test using a good solvent.
[2] The crosslinked polymer is a cured product of a curable compound 1 represented by Formula 1 described later, a cured product of a curable compound 2 represented by Formula 2 described later, and a curable compound 1 and the curable The composite according to [1], which is selected from the group consisting of cured products of composites of curable compounds composed of compound 2.
[3] The composite according to [1] or [2], wherein the metal nanowires are silver nanowires.
[4] The composite according to any one of [1] to [3], wherein the content of the metal nanowires calculated by thermogravimetry (TG) is 10% or more and 25% or less.
[5] A shape memory member comprising the composite according to any one of [1] to [4].
[6] A method for producing a composite according to any one of [1] to [4], which comprises a step of producing a molded body containing metal nanowires, and applying a composition containing a curable compound to the molded body. and applying energy to a molded article to which the composition is applied to cure the curable compound.
[7] The method according to [6], wherein the energy is applied by heating the compact.
[8] The method according to [6] or [7], wherein the energy is applied under pressurized conditions.
[9] The curable compound comprises a curable compound 1 represented by Formula 1 described later, a curable compound 2 represented by Formula 2 described later, and the curable compound 1 and the curable compound 2. The method according to any one of [6] to [8], which is selected from the group consisting of composites of curable compounds.

According to the present invention, it is possible to provide a composite that can be applied to a shape memory member that can be driven by local heating by applying an electric current.
Further, according to the present invention, it is possible to provide a method of manufacturing such a composite and a shape memory member including the composite.

1 is a schematic perspective view showing the structure of a composite according to one embodiment of the present invention; FIG. (a) A SEM image of silver nanowires synthesized in Example 2-1. (b) A SEM image of silver nanowires synthesized in Example 2-2. FIG. 4 is a SEM image of the composite prepared in Example 3-1. (a) surface, (b) cross section. 10 is a graph showing the relationship between power (W) and temperature (° C.) in the composite produced in Example 3-1. (a) to (f) are SEM images of the surface of three types of composites produced in Example 3-4 in permanent shape (before deformation) and temporary shape (after deformation). FIG. 4 shows DSC curves of composite 4(10), composite 4(20), composite 4(30), and composite 4(50) prepared in Example 4-1. FIG. 3 shows TG curves of complex 4 (10), complex 4 (20), complex 4 (30), and complex 4 (50). 4 is a graph showing stress (MPa) generated in a test piece in 20 repeated cycles of deformation and recovery as a function of test time (s). (a) Complex 4(10), (b) Complex 4(20), (c) Complex 4(30), (d) Complex 4(50).

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
Although the description of the constituent elements described below may be made based on representative embodiments of the present invention, the present invention is not limited to such embodiments.
In this specification, a numerical range represented by "-" means a range including the numerical values before and after "-" as lower and upper limits.

(Definition of terms)
As used herein, the term "permanent shape" means a state in which internal (residual) stress is relaxed in a target substance, in other words, the most thermodynamically stable shape. It refers to the shape obtained when a material is heated to near (or above) the melting temperature of the crystals in the absence of stress and then cooled to room temperature.
The melting temperature of the crystal means the temperature of the peak top of the endothermic peak in the temperature rising process of performing differential scanning calorimetry (DSC) of the substance of interest (when there are multiple endothermic peaks, the highest temperature side is the peak top temperature of the peak of ). The vicinity of the melting temperature means about the terminal temperature on the high temperature side of the endothermic peak in differential scanning calorimetry. In addition, differential scanning calorimetry shall be performed by the method mentioned later.

As used herein, the term “temporary shape” refers to a state in which a target substance is deformed by applying stress from the outside, heated to around the melting temperature of the crystal, and then cooled to about the crystallization temperature (or lower). This means the shape when the deformation is temporarily fixed by crystallization or the like. The crystallization temperature means the temperature of the peak top of the exothermic peak in the cooling process of the target substance measured by differential scanning calorimetry.

As used herein, the terms “driving,” “driving,” “drivable,” and “drivable” used with respect to the shape memory ability of the complex refer to the shape memory ability of the complex. It is possible for the complex to exhibit the shape memory ability, to exhibit the shape memory ability of the complex, and to exhibit the shape memory ability of the complex. It is intended to be (that the complex can exhibit shape memory ability).

[Complex]
FIG. 1 is a schematic perspective view showing the structure of a composite according to one embodiment of the present invention.
As shown in FIG. 1, a composite according to one embodiment of the present invention (hereinafter also referred to as "composite of the present embodiment") 100 is a composite including a crosslinked polymer 110 and metal nanowires 120. be. Note that FIG. 1 shows a mode in which the composite 100 of the present embodiment has a sheet-like appearance (also referred to as a film, a membrane, etc.), but the appearance of the composite 100 is particularly limited. can be determined as appropriate depending on the application.

In the composite 100 of this embodiment, the metal nanowires 120 are incorporated into the crosslinked polymer 110. In other words, in composite 100 , metal nanowires 120 do not simply partially cover the surface of crosslinked polymer 110 , but are embedded inside the crosslinked structure of crosslinked polymer 110 . With such a structure, composite 100 does not substantially cause detachment of metal nanowires 120 in a stability test described later.

In addition, in the composite 100 of the present embodiment, the metal nanowires 120 are incorporated into the crosslinked polymer 110 in such a dispersed state that the composite 100 can be driven by local heating by application of electric current. Due to such a structure, the composite 100 has constant conductivity. More specifically, in the conductivity test described later, the composite 100 was at least in a state before deformation (permanent shape) and a state in which stress was applied from the outside and deformed by 100% or more in a predetermined direction (temporary shape). shape) and has conductivity to the extent that electrical resistance can be measured. More preferably, the composite 100 further has conductivity to the extent that the electrical resistance can be measured even in a state in which energy is applied in a state of being deformed by 100% or more to restore the same size as before deformation. . Thereby, the composite 100 can be driven by local heating by application of electric current, and in a more preferable embodiment, can be repeatedly deformed and recovered multiple times.

Regarding the temporary shape in the conductivity test, the above 100% or more deformed state may be 100% deformation, 200% deformation, or 300% deformation. Deformation of more than 300% is acceptable. It has conductivity to the extent that electrical resistance can be measured in a state of being deformed at a higher rate, and even in a state where energy is applied in the deformed state to restore it to the same size as before deformation. It is desirable to have a measurable degree of electrical conductivity so that the composite 100 can be applied to a wider range of applications.

Furthermore, in the composite 100 of this embodiment, the metal nanowires 120 are incorporated into the crosslinked polymer 110 without substantially impairing the properties of the crosslinked polymer 110 alone. Specifically, the composite 100 has an endothermic peak and an exothermic peak in substantially the same temperature range in at least two or more samples produced under conditions in which the content (content rate) of the metal nanowires 120 is different. A peak is confirmed. This means that in the composite 100, the metal nanowires 120 are embedded inside the crosslinked structure of the crosslinked polymer 110, and the amount of the metal nanowires 120 thus incorporated into the crosslinked polymer 110 is It means that the melting point and crystallization temperature of the crosslinked polymer 110 contained in 100 are not substantially affected. As a result, the composite 100 can more effectively exhibit the shape memory ability (details will be described later) due to the inclusion of the crosslinked polymer 110, and the inclusion of the metal nanowires 120 allows localized It has a structure that additively or synergistically combines the features of the crosslinked polymer 110 and the metal nanowires 120 that they can be driven by heating.

In addition, in the composite 100 of the present embodiment, the metal nanowires 120 are incorporated into the crosslinked polymer 110 without substantially impairing the properties of the crosslinked polymer 110 alone. It also means that it is incorporated into the crosslinked polymer 110 without substantially impairing the properties that it has by itself. In other words, the metal nanowires 120 are embedded in the crosslinked structure of the crosslinked polymer 110, so that the composite 100 can be driven by local heating by applying an electric current. Instead, the properties of the metal nanowires 120 alone can be exhibited while incorporated in the crosslinked polymer 110 . Specifically, for example, in a mode in which metal nanowires 120 are silver nanowires, composite 100 can exhibit antibacterial properties derived from silver that constitutes the nanowires. As described above, in the composite 100 of the present embodiment, as described later, from the viewpoint of conductivity (that is, from the viewpoint of enabling driving by local heating by applying current), the material of the metal nanowires 120 is In addition to selecting the metal, it is also possible to select the metal from the viewpoint of imparting desired properties to the composite 100 .

The dispersion state of the metal nanowires 120 in the composite 100 described above can also be explained using the concept of percolation. The concept of percolation (the percolation problem) is well known in the art, as is its relationship to self-similarity. Given an n-dimensional lattice (eg, a cubic lattice), consider a procedure that occupies its site (or bond) parts with some probability p. If p≈1, the sites will all be connected, forming a network over the lattice. Conversely, if p≈0, few sites will be occupied and the surroundings of any occupied sites will remain empty. This process of stochastically occupying points or bonds in space is called percolation, and a group of mutually connected occupied sites is called a cluster. This can be thought of as an idealized model of the process of liquid penetration in random media and the process of forest fire propagation.

In the percolation problem, there exists a critical probability (percolation threshold) pc such that a cluster of connected bonds (or sites) of infinite size ( _percolation cluster) appears for the first time when p> _pc , and its value depends on the spatial dimension, whether it occupies a bond or a site, the lattice type, etc. Indeed, according to computer simulations, percolation clusters are self-similar and their fractal dimension D is D=91/48=about 1.89 in two dimensions and D=about 2.53 in three dimensions. I know it is. Note that the value of the fractal dimension D can be calculated from a scanning electron microscope (SEM) image of the object.

Based on the above, in the composite 100 of the present embodiment, it is preferable that the metal nanowires 120 have self-similarity based on the percolation cluster model described above or equivalent self-similarity. As a result, the composite 100 has excellent electrical conductivity and is suitable for use as a shape memory member that can be driven by local heating by applying an electric current.

[Crosslinked polymer]
The crosslinked polymer 110 contained in the composite 100 of this embodiment is a chemically crosslinked polymer compound. That is, the crosslinked polymer 110 is a high molecular compound having a crosslinked structure in which molecules are bonded to each other by covalent bonds formed by a chemical reaction.

The method of introducing a crosslinked structure into the polymer compound is not particularly limited, but a method of applying energy (typically by heating) to the curable compound (crosslinkable monomer) described below to cure it can be mentioned.

The crosslinked polymer 110 has an endothermic peak when differential scanning calorimetry (DSC) is performed. That is, the crosslinked polymer 110 has crystallinity such that an endothermic peak due to melting can be detected in differential scanning calorimetry, in other words, a melting peak can be detected. As a result, the composite 100 can exhibit a shape-memory ability to memorize the applied deformation and return to the shape before the deformation is applied when heated to the drive temperature.

Here, differential scanning calorimetry shall be performed under the following test conditions using a general differential scanning calorimeter.
<Test conditions for differential scanning calorimetry>
Measurement container: Aluminum sample pan Sample amount/size: Adjust appropriately according to the size of the sample pan.
Measurement start temperature: 0°C
Measurement end temperature: 120°C
Heating rate: set in the range of 0.01 to 20°C/min. Preferably, it is in the range of 5 to 10°C/min.
Measurement procedure: First, the sample is heated from room temperature to 120°C, and when it reaches 120°C, it is cooled to -5°C. Next, after the temperature of the sample reaches −5° C., the temperature is raised from 0° C. to 120° C. at a predetermined heating rate, and a DSC curve is obtained.

Although the melting peak temperature of the crosslinked polymer 110 is not particularly limited, it is preferably 33.0 to 58.0.degree.
In particular, when the composite is driven in contact with the surface of a living body as a wearable device or the like, the peak melting temperature of the crosslinked polymer 110 is preferably 33.0 to 37.0° C. in consideration of the surface temperature of the living body. 34.0 to 36.5°C is more preferable.
On the other hand, when the complex is placed or indwelled in vivo and driven, the melting peak temperature of the crosslinked polymer 110 is preferably 37.0 to 45.0° C. in consideration of the in vivo temperature. It is preferably above 0°C and below 44.0°C.

Although the degree of crystallinity of the crosslinked polymer 110 is not particularly limited, the degree of crystallinity obtained by differential scanning calorimetry is preferably 10.0 to 40.0%. When driving the complex on the surface of a living body, the crystallinity of the crosslinked polymer 110 is preferably 10.0 to 15.5%. When the complex is driven in vivo, the crystallinity of the crosslinked polymer 110 is preferably more than 15.5% and 40.0% or less, more preferably more than 15.5% and 28.0% or less, and the lower limit is 15.5%. Even more preferably, it exceeds 5%.

The crosslinked polymer 110 is not particularly limited as long as it has the crystallinity described above. A curable compound (crosslinkable monomer) for obtaining a cured product suitable for the crosslinked polymer 110 contained in the composite 100 of the present embodiment and an exemplary embodiment of a method for producing the same will be described below.

<Curable compound 1>
In one exemplary form, the crosslinked polymer 110 is a cured product of a curable compound 1 represented by Formula 1 below.

In Formula 1, L ¹ represents a poly(oxyalkylenecarbonyl) group, X ¹ represents a group having a curable group, and R ¹ is a hydrogen atom or a monovalent substituent having no curable group. , q1 represents an integer of 2 or more, p1 represents an integer of 0 or more, when q1 is 2 and p1 is 0, M1 represents a ^single bond or a divalent group, q1 is 2 and When p1 is 1 or more and q1 is 3 or more, M ¹ represents a p1+q1-valent group, and a plurality of R ¹ and L ¹ may be the same or different.

The poly(oxyalkylenecarbonyl) group of L ¹ in formula 1 is a divalent group consisting of a polymer chain having an oxyalkylenecarbonyl group as a repeating unit, specifically represented by the following formula II is the base.

In Formula II, L ²¹ represents an alkylene group, and although the number of carbon atoms in the alkylene group of L ²¹ is not particularly limited, it is preferably 1-20, more preferably 2-10.
Among them, an alkylene group having 2 to 10 carbon atoms is more preferable as L ²¹ from the viewpoint of obtaining a composite having superior effects of the present invention.

Also, in formula II, n represents a number of 2 or more and is not particularly limited, but is preferably 2 to 200, more preferably 2 to 100. 5 to 50 are more preferred, and 10 to 30 are particularly preferred.

As will be described later, the curable compound 1 can also be prepared by ring-opening polymerization of a cyclic ester. In this case, the number of n can be adjusted by the charge ratio of the ring-opening polymerization initiator (eg, polyhydric alcohol) and the monomer (eg, lactone compound). More specifically, the desired n number of lactone compounds may be prepared to react with one hydroxy group of the polyhydric alcohol.

The number n can be determined by ¹ H-NMR (Nuclear Magnetic Resonance) measurement of the cured product.

Returning to Formula 1, X ¹ is a group having a curable group. As used herein, a group having a curable group means a curable group itself or an atomic group having a curable group as a partial structure in its structure.
Although the group having a curable group for X ¹ is not particularly limited, a group represented by the following formula (III) is preferable.

In Formula ^III , Z represents a curable group and L3 represents a single bond or a divalent group. Moreover, "*" represents a binding position.
The divalent group of L ³ is not particularly limited, but -C(O)-, -C(O)O-, -OC(O)-, -O-, -S-, -NR ²⁰ -(R ²⁰ represents a hydrogen atom or a monovalent organic group), an alkylene group (preferably having 1 to 10 carbon atoms), a cycloalkylene group (preferably having 3 to 10 carbon atoms), an alkenylene group (preferably having 2 to 10 carbon atoms is preferred), and combinations thereof. Among them, L ³ is a single bond, —O—, —C(O)—, an alkylene group, —NR ²⁰ —, and , and combinations of these are preferred.

In Formula III, the curable group of Z refers to a group that participates in the curing reaction. The curable group is not particularly limited, but is preferably a group capable of radical polymerization, and more preferably a group having an ethylenically unsaturated bond, in that a composite having superior effects of the present invention can be obtained. Although the group having an ethylenically unsaturated bond is not particularly limited, examples thereof include (meth)acryloyl groups, styryl groups, and allyl groups, among which (meth)acryloyl groups are preferred.
In addition, in this specification, "(meth)acryloyl" means either one or both of acryloyl and methacryloyl.

Returning to Formula 1, the form of the p+q ^- valent group of M ¹ is not particularly limited when M ¹ is a divalent group. groups are preferred.

When M ¹ is a group having a valence of 3 or more, it is not particularly limited, and examples thereof include groups represented by the following formulas (4a) to (4d).

In formula 4a, L3 represents a _trivalent group. T3 represents a single bond or a divalent group, and _three _T3s may be the same or different.
L ₃ is a nitrogen atom, a trivalent hydrocarbon group (preferably having 1 to 10 carbon atoms; the hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group), or Examples thereof include trivalent heterocyclic groups (preferably 5- to 7-membered heterocyclic groups), and the hydrocarbon groups may contain a heteroatom (eg, —O—). Specific examples of L3 include glycerol residue _, trimethylolpropane residue, phloroglucinol residue, and cyclohexanetriol residue.

In formula 4b, L4 represents a _tetravalent group. T4 represents a single bond or a divalent group, and _four _T4s may be the same or different.
A preferred form of L ₄ is a tetravalent hydrocarbon group (preferably having 1 to 10 carbon atoms. The hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.), A tetravalent heterocyclic group (preferably a 5- to 7-membered heterocyclic group) may be mentioned, and the hydrocarbon group may contain a heteroatom (eg, —O—). Specific examples of _L4 include a pentaerythritol residue, a ditrimethylolpropane residue, and the like.

In formula 4c, L5 represents a _pentavalent group. T5 represents a single bond or a divalent group, and _five _T5s may be the same or different.
A preferred form of L ₅ is a pentavalent hydrocarbon group (preferably having 2 to 10 carbon atoms. The hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.), or , a pentavalent heterocyclic group (preferably a 5- to 7-membered heterocyclic group), and the hydrocarbon group may contain a heteroatom (eg, —O—). Specific examples of _L5 include arabinitol residue, phloroglucidol residue, cyclohexanepentaol residue and the like.

In formula 4d, L6 represents a _hexavalent group. T6 represents a single bond or a divalent group, and _six _T6s may be the same or different.
A preferred form of L ₆ is a hexavalent hydrocarbon group (preferably having 2 to 10 carbon atoms. The hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.), or , a hexavalent heterocyclic group (preferably a 6- to 7-membered heterocyclic group), and the hydrocarbon group may contain a heteroatom (eg, —O—). Specific examples of L6 include mannitol residue, sorbitol residue, dipentaerythritol residue, _{hexahydroxybenzene} , and hexahydroxycyclohexane residue.

In Formulas 4a to 4d, the divalent groups represented by T ₃ to T ₆ may have the same form as the divalent group of M ¹ already explained, or may be the same.
Further, when M ¹ is a group having a valence of 7 or more, a group obtained by combining the groups represented by formulas 4a to 4d can be used.

Returning to Formula 1, p1 represents an integer of 0 or more, preferably 2 or less, more preferably 1 or less, and still more preferably 0.
Moreover, q1 represents an integer of 2 or more, preferably 4 or less, more preferably 3 or less, and still more preferably 2.

In Formula 1, R ¹ represents a hydrogen atom or a monovalent substituent having no curable group.
The monovalent substituent having no curable group is not particularly limited, but includes, for example, a group represented by *-L''-R'.
In the above formula, L″ represents a single bond or a divalent group, and R′ represents a hydrogen atom or a hydrocarbon group (linear, branched, or cyclic). good), and * represents the binding position.

The curable compound 1 is preferably a compound represented by the following formula 1B in terms of obtaining a composite having superior effects of the present invention.

In Formula 1B, M ^1B is an r1valent group, and its form, including preferred forms, is the same as the group represented by M ¹ in Formula 1 already described.
L ^1B represents a poly(oxyalkylenecarbonyl) group, X ^1B represents a group having a curable group, and its form, including preferred forms, is the same as L ¹ and X ¹ in formula 1 already described. be.

The curable compound 1 is preferably a compound represented by the following formula 1D in that a composite having even more excellent effects of the present invention can be obtained.

In Formula 1D, AL ² represents an alkylene group having 1 to 20 carbon atoms. Although the number of carbon atoms in the alkylene group is not particularly limited, it is preferably 3 or more, and preferably 10 or less. L ^D represents a hydrocarbon having 1 to 5 carbon atoms, and includes -CH ₂ CH ₂ -, -CH ₂ CH _{2 CH 2 -, -CH 2 CH 2 CH 2} _CH ₂ _- _, _and -CH ₂ C(CH ₃ ) ₂ CH ₂ — is preferred, and —CH ₂ CH ₂ CH ₂ CH ₂ — is more preferred. X ^1D represents a group having a curable group, and its form, including preferred forms, is the same as the group represented by X ¹ in formula 1 already described.

In Formula 1D, w represents an integer of 2 or more, preferably 100 or less, more preferably 50 or less, and preferably an integer of 20 or less.

Although the number average molecular weight of the curable compound 1 is not particularly limited, it is generally preferably from 2,000 to 8,000.
Also, the molecular weight distribution (Mw/Mn) of the curable compound 1 is not particularly limited, but is generally preferably from 1.1 to 1.6.
The number average molecular weight and weight average molecular weight of the curable compound 1 mean values determined by GPC (Gel Permeation Chromatography) measurement by the method described in Examples below.

<Curable compound 2>
In another exemplary form, crosslinked polymer 110 is a cured product of curable compound 2 represented by Formula 2 below.

L ² represents a polymer chain, the polymer chain includes all repeating units composed of an oxyalkylenecarbonyl group, repeating units derived from D-lactic acid, and repeating units derived from L-lactic acid, and X ² is Represents a group having the same curable group as that of X ¹ in Formula 1, R ² represents a hydrogen atom or a monovalent substituent having no curable group, q2 is an integer of 2 or more and p2 represents an integer of 0 or more, when q2 is ² and p2 is 0, M2 represents a single bond or a divalent group, when q2 is 2 and p2 is 1 or more, and When q2 is 3 or more, M ² represents a p2+q2-valent group, and multiple R ² and L ² may be the same or different.

The polymer chain of L ² in Formula 2 is a polymer chain containing all repeating units consisting of an oxyalkylenecarbonyl group, repeating units derived from D-lactic acid, and repeating units derived from L-lactic acid. ^The polymer chain of L2 may have repeating units other than the above, in which case a poly(oxyalkylene) group (chain) is preferred.

Lactic acid has two types of optical isomers, L-lactic acid and D-lactic acid, represented by the following formulas, and polylactic acid polymers can be obtained by polyesterifying these.

Typically, lactic acid can be polymerized by converting it to cyclic lactide and ring-opening polymerization as shown in the following formula. In the present specification, the repeating unit of the polymer derived from D-lactic acid is referred to as "repeating unit derived from D-lactic acid", and the repeating unit of the polymer derived from L-lactic acid is referred to as "derived from L-lactic acid." It is called a repeating unit that

Therefore, the polymer chain of L2 consists of repeating units of P1 represented by the following ^formula (repeating units consisting of an oxyalkylenecarbonyl group), P2D (repeating units derived from D-lactic acid), and P2L (L- repeating unit derived from lactic acid). In the formula below, n represents an integer of 1 to 20, preferably an integer of 2 to 10, more preferably an integer of 3 to 8.

The arrangement order of the P1 unit, P2D unit, and ^P2L unit in the L2 polymer chain is not particularly limited, and may be random, triblock, or multiblock. From the viewpoint of easily controlling the melting point of the polymer chain of L2, it is preferably arranged at random ⁽ random copolymer). ^In the cured product (crosslinked product), the polymer chain of L2 becomes a polymer chain located between the crosslink points. It is difficult to have a structure or an extended chain structure, and the melting point of the cured product becomes lower, or the cured product does not have a melting point (has no crystallinity).

The content of P1 units, P2D units, and ^P2L units in L2 is not particularly limited. well, may be 10 mol% or more, may be 20 mol% or more, may be 30 mol% or more, may be 40 mol% or more, or may be 50 mol% or more It may be 60 mol % or more. When the crosslinked polymer is composed only of the cured product of curable compound ² , the content of P1 units in L2 is preferably more than 60 mol% and less than 100 mol%. The upper limit may be 90 mol % or less, 80 mol % or less, or 70 mol % or less.
Further, the content of the P2D unit and the P2L unit may be 1 to 5 mol%, may be 5 mol% or more, may be 10 mol% or more, and may be 15 mol%. or more. The upper limit may be 45 mol% or less, 40 mol% or less, 35 mol% or less, 30 mol% or less, or 25 mol% or less. may be present, or may be 20 mol % or less. When the crosslinked polymer is composed only of the cured product of curable compound ² , the content of P2D units and P2L units in L2 is preferably 1 mol % or more and less than 20 mol %. In this case, the upper limit may be 15 mol % or less, 10 mol % or less, or 5 mol % or less.

The number of repetitions of the P1 unit, the P2D unit, and the P2L unit in the polymer chain is not particularly limited, but the number of repetitions is preferably 10 or more, more preferably 20 or more, from the viewpoint that the deformation rate of the cured product tends to increase. , is more preferably 30 or more, preferably 200 or less, more preferably 100 or less, and even more preferably 70 or less.

In one exemplary preferred aspect, the total number of repeating P1 units, P2D units and ^P2L units in L2 is 10-100.

Returning to Formula ² , X2 is a group having a curable group. ^The curable group possessed by X2 is the same as the curable group possessed by X1 in formula ( ¹ ). Further, specific examples of the group of X2 ^are the same as those of the group of ^X1 , and the preferred forms are also the same.
In addition, the monovalent substituents for R ² are the same as the monovalent substituents for R ¹ in Formula 1, and the preferred forms are also the same.
In addition, the divalent group and trivalent or higher group of M ² are the same as the divalent group and trivalent or higher group of M ¹ in Formula 1, respectively, and the preferred forms are also the same. is.

In Formula 2, p2 represents an integer of 0 or more, preferably 2 or less, more preferably 1 or less, and still more preferably 0.
Moreover, q2 represents an integer of 2 or more, preferably 3 or more, preferably 8 or less, and more preferably 6 or less.

The curable compound 2 is preferably a compound represented by the following formula 1C, in that a composite having superior effects of the present invention can be obtained.

In Formula 1C, M ^1C is an r2valent group, L ^1C represents a polymer chain, and the polymer chain is a repeating unit composed of an oxyalkylenecarbonyl group, a repeating unit derived from D-lactic acid, and L - containing all repeating units derived from lactic acid (which may further contain a poly(oxyalkylene) group), X ^1C represents a group having the same curable group as that of X ^1B in Formula 1B, and r2 is represents an integer of 2 or more, and a plurality of L ^1C may be the same or different.

Here, the polymer chain of L ^1C , the divalent or trivalent group of M 1 ^C , or the curable group of X ^1C are, respectively, the polymer chain of L ² in formula 2, the divalent of M ² , Alternatively, a group having a valence of 3 or more and a group similar to the curable group of X ² can be mentioned, and the preferred forms are also the same.
r2 is preferably an integer of 2 or more, preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. When r2 is within the above numerical range, a composite having superior effects of the present invention can be obtained.

The curable compound 2 is preferably a compound represented by the following formula 1E, from the viewpoint of obtaining a composite having more excellent effects of the present invention.

In Formula 1E, L ^1Ea represents a polymer chain and includes all repeating units consisting of an oxyalkylenecarbonyl group, repeating units derived from D-lactic acid, and repeating units derived from L-lactic acid, and L ^1Eb is It represents a polymer chain consisting of a single bond or a poly(oxyalkylene) group (chain), and X ^1E represents a group having the same curable group as that of X ^1D in Formula 1D.

Here, the polymer chain of L ^1E and the group having a curable group of X ^1E are the same groups as the polymer chain of L ² and the group having a curable group of X ² in Formula 2, respectively. The same applies to preferred forms.

Although the number average molecular weight of the curable compound 2 is not particularly limited, it is generally preferably from 8,000 to 40,000. Also, the molecular weight distribution (Mw/Mn) of the curable compound is not particularly limited, but is generally preferably from 1.10 to 1.80.
The number average molecular weight and weight average molecular weight of the curable compound 2 mean values determined by GPC (Gel Permeation Chromatography) measurement by the method described in Examples below.

<Method for producing curable compound>
Here, a method for producing curable compound 1 and curable compound 2 (hereinafter collectively referred to simply as "curable compound") will be described.
The method for producing the curable compound is not particularly limited, but in order to obtain the curable compound more easily, a group having a curable group is introduced into the precursor compound obtained by ring-opening polymerization of the cyclic compound. is preferably obtained by

As the cyclic compound, known cyclic compounds can be used without particular limitation, but those that can be ring-opened by hydrolysis are preferred, such as β-propiolactone, β-butyrolactone, β-valerolactone, γ- Butyrolactone, γ-valerolactone, γ-caprylolactone, δ-valerolactone, β-methyl-δ-valerolactone, δ-stearolactone, ε-caprolactone, γ-octanoic lactone, 2-methyl-ε- Cyclic esters (lactone compounds) such as caprolactone, 4-methyl-ε-caprolactone, ε-caprylolactone, ε-palmitolactone, α-hydroxy-γ-butyrolactone, and α-methyl-γ-butyrolactone; glycolide, and cyclic diesters such as lactide;

Among them, the cyclic compound is preferably a lactone compound or lactide, and the lactone compound is β-propiolactone, β-butyrolactone, β-valerolactone, γ- Butyrolactone, γ-valerolactone, γ-caprylolactone, δ-valerolactone, β-methyl-δ-valerolactone, δ-stearolactone, ε-caprolactone, 2-methyl-ε-caprolactone, 4-methyl-ε -caprolactone, ε-caprylolactone, and ε-palmitolactone is more preferably at least one selected from the group consisting of.

In particular, lactide can be used in the synthesis of the curable compound 2. Examples of this lactide include L-lactide (LL lactide) formed by dehydration condensation of two molecules of L-lactic acid, two molecules of D - D-lactide (DD-lactide) formed by dehydration condensation of lactic acid, meso-lactide formed by dehydration condensation of one molecule of L-lactic acid and one molecule of D-lactic acid, and D-lactide and L -DL-lactide (racemic lactide), which is a mixture of equal amounts of lactide, and the like. DL-lactide is preferred because the melting point of the resulting cured product tends to be lower.

The method of obtaining a precursor compound by ring-opening polymerization of a cyclic compound is not particularly limited, but a method of ring-opening polymerization using an alcohol as an initiator in the presence of a metal catalyst can be mentioned.

-Metal catalyst Although not particularly limited as a metal catalyst, alkali metals, alkaline earth metals, rare earths, transition metals, aluminum, germanium, tin, and fatty acid salts such as antimony, carbonates, sulfates, phosphates, oxides, hydroxides, halides, alcoholates, and the like.
More specifically, stannous chloride, stannous bromide, stannous iodide, stannous sulfate, stannic oxide, stannous myristate, tin octoate (Tin (II)-ethylhexanoate), stearin Tin acid, tetraphenyltin, tin methoxide, tin ethoxide, tin butoxide, aluminum oxide, aluminum acetylacetonate, aluminum isopropoxide, aluminum-imine complex, titanium tetrachloride, ethyl titanate, butyl titanate, glycol titanate, titanium tetra Compounds such as butoxide, zinc chloride, zinc oxide, diethyl zinc, antimony trioxide, antimony tribromide, antimony acetate, calcium oxide, germanium oxide, manganese oxide, manganese carbonate, manganese acetate, magnesium oxide, and yttrium alkoxide. be done.

The amount of the metal catalyst used is preferably about 0.01×10 ⁻⁴ to 100×10 ⁻⁴ mol per 1 mol of the cyclic compound in terms of the metal element in the metal catalyst.

• Initiator Although the initiator is not particularly limited, monohydric or dihydric or higher alcohols can be mentioned.

The monohydric alcohol is not particularly limited, but includes an alcohol represented by R ^IN —OH, where R ^IN is an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms. show.
Examples of the aliphatic hydrocarbon group include, but are not limited to, alkyl groups having 1 to 20 carbon atoms.
Examples of monohydric alcohols include methanol, ethanol, n-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, pentyl alcohol, n-hexyl alcohol, cyclohexyl alcohol, octyl alcohol, nonyl alcohol, 2-ethylhexyl alcohol, Examples include n-decyl alcohol, n-dodecyl alcohol, hexadecyl alcohol, lauryl alcohol, ethyl lactate and hexyl lactate.

Dihydric or higher alcohols (polyhydric alcohols) include ethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, trimethylolethane, ditrimethylolethane, trimethylolpropane, and ditrimethylol. Propane, pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, diglycerol, and pentaerythritol ethoxylate.

Among them, a dihydric alcohol or a tetrahydric alcohol is preferable in terms of obtaining a composite having a more excellent effect of the present invention. Examples of the dihydric alcohol include ethylene glycol, 1,3-propanediol, , 4-butanediol, and neopentyl glycol are preferred.
As the tetrahydric alcohol, pentaerythritol, pentaerythritol ethoxylate, and the like are preferable.
The amount of the initiator used is not particularly limited, but is preferably about 0.0001 to 0.1 mol per 1 mol of the cyclic compound.

- Ring-opening polymerization Ring-opening polymerization is preferably carried out in an inert gas atmosphere in order to prevent volatilization of the cyclic compound. The polymerization temperature is not particularly limited, but preferably 100 to 250°C.
Although the polymerization time is not particularly limited, it is preferably about 0.1 to 48 hours.

・Introduction of curable group The method of introducing a curable group into a precursor compound obtained by ring-opening polymerization of a cyclic compound is not particularly limited. A method (a) of reacting a compound having both a substituent and a curable group, and a functional group that is reactive to the substituent by substituting the hydroxy group of the precursor compound with another functional group. and a method (b) of reacting a compound having both a group and a curable group. Among them, the method (a) is preferable in that the curable compound (macromonomer) can be obtained more easily.

In the method (a) above, the compound to be reacted with the hydroxy group of the precursor compound is not particularly limited. For example, when the curable group is a (meth)acryloyl group, (meth)acrylic acid chloride, and Examples include unsaturated acid halogen compounds such as brominated (meth)acrylic acid.
The amount of the compound to be reacted with the hydroxy group of the precursor compound is not particularly limited, but is preferably about 0.1 to 20 molar equivalents relative to the hydroxy group.

<Composite of curable compound>
In another exemplary form, the crosslinked polymer 110 is a cured composite of curable compounds composed of curable compound 1 and curable compound 2 above.

The contents of the curable compound 1 and the curable compound 2 in the composite of the curable compounds are not particularly limited as long as they have the crystallinity described above. For example, the contents of the curable compound 1 and the curable compound 2 can be adjusted so that the melting peak temperature of the crosslinked polymer is within the desired range in consideration of the use of the composite.

Specifically, the content of the curable compound 1 is preferably 20 mol% or more, more preferably 30 mol% or more, more preferably 35 mol% or more, when the total is 100 mol%, in relation to the curable compound 2. mol % or more is more preferable, and 40 mol % or more is particularly preferable.
The upper limit is preferably 99 mol% or less, more preferably 95 mol% or less, still more preferably 90 mol% or less, and particularly preferably 85 mol% or less.

In particular, when the composite is driven on the surface of a living body, the content of curable compound 1 is preferably 45 to 65 mol %.
Moreover, when the composite is driven in vivo, the content of the curable compound 1 is preferably 65 to 99 mol %, more preferably 65 to 85 mol %.

The content of the curable compound 2, in relation to the curable compound 1, is preferably 1 mol% or more, more preferably 5 mol% or more, and further preferably 10 mol% or more when the total is 100 mol%. It is preferably 15 mol% or more, particularly preferably 80 mol% or less, more preferably 70 mol% or less, still more preferably 65 mol% or less, and particularly preferably 60 mol% or less.

In particular, when the composite is driven on the surface of a living body, the content of the curable compound 2 is preferably 35 to 50 mol %.
Moreover, when the composite is driven in vivo, the content of the curable compound 2 is preferably 1 to 35 mol %, more preferably 10 to 35 mol %.

In a preferred exemplary embodiment, the molar ratio of the content of curable compound 2 to the content of curable compound 1 and curable compound 2 in the composite of curable compounds ([curable compound 2]/ [Curable compound 1+Curable compound 2]) is from 0.01 to 0.65.

In another exemplary preferred embodiment, the specimen prepared by the following method has crystallinity from the viewpoint that the cured product of the composite of the curable compound can have both a lower melting point and a higher deformation rate. preferably not.

Test body preparation method: A composition obtained by mixing 500 mg of curable compound 2, 15 mg of benzoyl peroxide, and 695 μL of xylene is heated to 80° C. to polymerize, and the obtained polymer is treated with acetone. After washing with , shrinking in methanol and drying under reduced pressure, a specimen is obtained.

<Cured product>
Shape memory materials suitable for the crosslinked polymer 110 contained in the composite 100 of the present embodiment include the cured product of the curable compound 1, the cured product of the curable compound 2, and the curable compound 1 and the curable compound. The method of obtaining a cured product of a composite of curable compounds composed of 2 is not particularly limited, but energy is applied to a composition containing curable compound 1 and curable compound 2 and, if necessary, other components. can be obtained by curing (typically by heating). The details are described in the section on "Method for producing a composite" below.

[Metal nanowires]
The material of the metal nanowires (hereinafter also simply referred to as “metal nanowires”) 120 included in the composite 100 of the present embodiment is metal. The metal as the material of the metal nanowires 120 does not include ceramics such as metal oxides and nitrides. Specific examples include iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, silver, cadmium, osmium, iridium, platinum, and gold. Among them, copper, silver, platinum, and gold are preferable, and silver is more preferable, from the viewpoint of conductivity.

The shape of the metal nanowires 120 is not particularly limited as long as the ratio of the length in the short axis direction to the length in the long axis direction (hereinafter also referred to as “aspect ratio”) is 10 or more. From the point of view of synthesis and composite manufacturing, if the aspect ratio is too large, it may become difficult to handle. Therefore, the aspect ratio is preferably 10000 or less, more preferably 1000 or less.

The metal nanowires 120 may have a straight shape, a branched shape, a shape in which particles are connected in a beaded shape, or a mixture of these shapes. Here, the linear metal nanowire means that the shape is rod-like, and the branched metal nanowire means that the shape is branched. If the metal nanowires have low rigidity and are partially or wholly curved or bent, they are included in the linear metal nanowires.

The length of the metal nanowires 120 in the minor axis direction is not particularly limited, but is preferably 1 nm or more and 1 μm or less. If the length in the minor axis direction is too short, synthesis of metal nanowires tends to be difficult, so the length is more preferably 10 nm or more and 500 nm or less. Although the length of the metal nanowires in the major axis direction is not particularly limited, it is preferably 1 μm or more and 1 mm or less from the viewpoint of conductivity. Moreover, if the length in the major axis direction is too long, it may become difficult to handle.
The shape and size of metal nanowires 120 can be confirmed with a scanning electron microscope or a transmission electron microscope.

The metal nanowires 120 can be synthesized by a known method. For example, a method of reducing silver nitrate in a solution, a method of applying voltage or current from the tip of the probe to the surface of the precursor to extract metal nanowires at the tip of the probe, and forming the metal nanowires continuously. is mentioned. Specific examples of the method for reducing silver nitrate in a solution include a method of reducing nanofibers composed of metal-complexed peptide lipids (JP-A-2002-266007) and a method called polyol reduction, in which ethylene A method of reduction while heating in glycol (Y. Sun, et al., Chem Mater., 2002, 14(11), 4736-4745.), a method of reduction in sodium citrate (K. K. Caswell, et al., Nano Lett., 2003, 3(5), 667-669.). Among them, the method of reducing while heating in ethylene glycol is preferable because metal nanowires with high crystallinity can be synthesized relatively easily.

The content of the metal nanowires 120 in the composite 100 of the present embodiment is not particularly limited as long as it is sufficient to drive the composite 100 by local heating due to the application of electric current.

Specifically, the content of metal nanowires 120 calculated by thermogravimetry (TG) is preferably 5% or more, more preferably 10% or more, and further preferably 15% or more. It is preferably 20% or more, and more preferably 20% or more. Thereby, the metal nanowires 120 can be incorporated into the crosslinked polymer 110 in a dispersed state in the composite 100 to such an extent that the composite 100 can be driven by local heating by applying an electric current. The thermogravimetric measurement shall be performed by the method described in Examples below.

On the other hand, since one of the features of the composite 100 of the present embodiment is that it can be driven by local heating due to the application of electric current, the content of the metal nanowires 120 should be higher than necessary. is not required. From such a viewpoint, the content of the metal nanowires 120 calculated by thermogravimetry (TG) is preferably 60% or less, more preferably 50% or less, and 40% or less. More preferably, it is even more preferably 35% or less. By setting the content rate of the metal nanowires 120 to a lower value, it is possible to avoid adverse effects such as unintended transfer of Joule heat generated by the application of current to the surrounding environment. On the other hand, depending on the application of the composite, there may be cases where it is not necessary to consider the propagation and diffusion of Joule heat to the surrounding environment so much. Therefore, the content of metal nanowires 120 may be 5% or more and 60% or less, or may be 5% or more and 50% or less, as long as the composite has conductivity to the extent that the electrical resistance can be measured. well, may be 5% or more and 40% or less, may be 5% or more and 35% or less, may be 10% or more and 35% or less, may be 15% or more and 35% or less, It may be 20% or more and 35% or less.

[Conductive Conductivity of Composite]
As described above, the composite 100 of the present embodiment has a structure in which the metal nanowires 120 are incorporated into the crosslinked polymer 110, so that both the permanent shape and the temporary shape have conductivity to the extent that electrical resistance can be measured. have sex.

The conductivity test of the composite is performed by preparing a test piece of any size, at least in a permanent shape (state before deformation), in a state of being stretched 100% using a tensile tester, and applying energy (typically Specifically, the electrical resistance (Ω) shall be measured under three conditions in a 100% contracted state (restored to the same size as before deformation) by heating.
A specific test method when the test piece is in the form of a sheet is as described in Examples below. If the test piece has a shape other than a sheet shape, those skilled in the art can appropriately change the design.

[Structural stability of complex]
Moreover, as described above, the composite 100 of the present embodiment has a structure in which the metal nanowires 120 are incorporated into the crosslinked polymer 110, and therefore has excellent structural stability.

Specifically, in the stability test using a good solvent for the crosslinked polymer 110 and/or the metal nanowires 120, the composite 100 does not substantially detach the metal nanowires 120.

Here, "substantially does not cause detachment of the metal nanowires" means that suspension of the test solvent caused by the metal nanowires detached from the composite is observed visually before and after the stability test. It means that it is substantially not observed and/or that weight measurement of the test piece before and after the stability test does not show a decrease in weight due to the metal nanowires detached from the composite. do. In practice, a small amount of the test solvent may remain in the test piece after the stability test. or a slight increase over the weight before testing. On the other hand, in a test piece made of a material having no structure like the composite 100 of this embodiment, the weight after the test clearly decreases from the weight before the test.

The solvent used in the stability test, that is, the good solvent for the crosslinked polymer 110 and/or the metal nanowires 120 is not particularly limited, and may be appropriately selected according to the structure/materials of the crosslinked polymer and/or the metal nanowires. Specific examples include alcohols such as methanol, ethanol, and 1-propanol.
A specific test method when the test piece is in the form of a sheet is as described in Examples below. If the test piece has a shape other than a sheet shape, those skilled in the art can appropriately change the design.

[Manufacturing method of composite]
The method for producing the composite 100 of the present embodiment is not particularly limited, but the following production is possible in that a composite that can be applied to a shape memory member that can be driven by local heating by applying an electric current can be obtained more easily. A method is preferred.

A method for producing a composite according to one embodiment of the present invention (hereinafter, also referred to as “the production method of the present embodiment”) comprises:
a step of producing a molded body containing metal nanowires (hereinafter also referred to as a “molded body manufacturing step”);
a step of applying a composition containing a curable compound to the molded body (hereinafter also referred to as a "composition applying step");
a step of applying energy to the molded article to which the composition is applied to cure the curable compound (hereinafter also referred to as a “curing step”);
including.
Below, each said process is demonstrated.

(Molding body manufacturing process)
The compact preparation step is a step of preparing a compact containing metal nanowires. Specifically, metal nanowires are dispersed in an arbitrary solvent to prepare a metal nanowire dispersion solution, which is applied on an arbitrary support, and the solvent is dried at a predetermined temperature to form a molding containing metal nanowires. you can get a body

The solvent for dispersing the metal nanowires is not particularly limited, and examples include alcohols such as methanol, ethanol, and 1-propanol, and DMF (N,N-dimethylformamide), etc., which are liquid at room temperature and volatile. organic solvents excellent in

(Composition application step)
The composition applying step is a step of applying a composition containing a curable compound to the molded article obtained in the molded article producing step.

The curable compound contained in the composition is not particularly limited, but the curable compound 1 described above, the curable compound 2, and a composite of a curable compound composed of the curable compound 1 and the curable compound 2 It is preferably selected from the group consisting of

As long as the composition contains the curable compound described above, it may contain other components as necessary. Other ingredients include, for example, curing agents and solvents.

<Curing agent>
A curing agent is a compound having a function of acting on a curable compound to cause a curing reaction.
The curing agent is not particularly limited, and known compounds can be used, and radical polymerization initiators are typically preferred. As the curing agent, a thermosetting agent in which a curing reaction proceeds by application of heat energy and/or a photo-curing agent in which a curing reaction proceeds by light irradiation (application of light energy) can be used.

Examples of heat curing agents include azo compounds such as azobisisobutyronitrile and peroxides such as benzoyl peroxide.
Examples of photocuring agents include aromatic ketone compounds such as benzophenone, Michler's ketone, xanthone, and thioxanthone; quinone compounds such as 2-ethylanthraquinone; acetophenone, trichloroacetophenone, 2-hydroxy-2-methylpropiophenone, 1 - acetophenone compounds such as hydroxycyclohexylphenyl ketone, benzoin ether, 2,2-diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone; diketone compounds such as methylbenzoylformate; 1-phenyl-1,2- Acyl oxime ester compounds such as propanedione-2-(O-benzoyl) oxime; acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide; tetramethylthiuram and sulfur compounds such as dithiocarbamate; Organic peroxides such as benzoyl oxide; azo compounds such as azobisisobutyronitrile; organic sulfonium salt compounds; iodonium salt compounds;

The content of the curing agent in the composition is preferably 0.001 to 10% by mass with respect to the total mass of curable compounds in the composition. The composition may contain one type of curing agent alone, or may contain two or more types. When the composition contains two or more curing agents, the total content is preferably within the above numerical range.

<Solvent>
The composition may contain a solvent. The solvent contained in the composition is not particularly limited, but a solvent that can dissolve and/or disperse the curable compound and the curing agent and that is difficult to evaporate during the curing reaction may be selected.
For example, when benzoyl peroxide (BPO) is used as the curing agent, the curing reaction temperature is about 80° C., so a solvent having a boiling point equal to or higher than the curing reaction temperature is preferable. Evaporation of the solvent during the curing reaction can be further suppressed by using such a solvent, so that a cured product with less inclusion of air bubbles can be easily obtained. Such solvents include, for example, xylene, butyl acetate, DMF, dimethylsulfoxide, and the like.

On the other hand, when a photocuring agent is used as a curing agent, the temperature of the curing reaction is generally lower than when using a heat curing agent, so even if a solvent with a lower boiling point is used, a cured product with fewer air bubbles can be obtained. . Examples of solvents that can be used include dichloromethane, chloroform, and acetone.

The content of the solvent in the composition is not particularly limited, but when the composition contains a solvent, it is preferably 10 to 90% by mass when the total mass of the composition is 100% by mass. The composition may contain one type of solvent alone or may contain two or more types. When the composition contains two or more solvents, the total content is preferably within the above numerical range.

(Curing process)
The curing step is a step of applying energy to the molded article to which the composition is applied to cure the curable compound.

In the curing step, the type of energy to be applied to the molded body may be appropriately selected depending on the type of curing agent that may be contained in the composition described above, and heating and/or light irradiation are preferred.

The method of applying energy is not particularly limited, but includes, for example, a method of heating a molded article formed on a support and/or irradiating the molded article with light to cure the curable compound.
The heating temperature/heating time, the intensity of light irradiation/irradiation time, etc. may be appropriately selected according to the shape of the molded article, the type of curing agent, and the like.
More specifically, the heating temperature may be, for example, 40 to 200.degree. Also, the heating time may be, for example, 1 minute to 24 hours.

In addition, the application of energy to the molded body may be performed under pressurized conditions. Thereby, the metal nanowires can be more efficiently incorporated into the crosslinked structure of the cured product during the curing process of the curable compound. As a result, the obtained composite tends to have a structure in which the metal nanowires are effectively embedded inside the crosslinked structure of the crosslinked polymer. The pressure to be applied may be appropriately adjusted according to the shape and thickness of the molded body.

Furthermore, the production method of the present embodiment includes a step of drying the obtained product (composite containing metal nanowires and a cured product of a curable compound) after the curing step (hereinafter, also referred to as a “drying step”. ) may be included.

The drying step is a step of drying the product to remove at least part of the solvent contained in the product. The drying method is not particularly limited, and examples thereof include a method of standing at 20 to 50° C. for 1 minute to 24 hours, and a method of holding under reduced pressure. The drying conditions may be appropriately selected according to the shape and thickness of the product.

The size and shape of the hardened product are not particularly limited. It may be determined as appropriate according to the application. The cured product has a shape memory ability, a lower driving temperature, and an excellent deformation rate, so that it can be applied to medical instruments such as ligatures and sutures. Moreover, this hardened|cured material can also be used as a film|membrane taking advantage of shape memory ability. For example, if the base material of an adhesive tape having a base material and an adhesive layer disposed on the base material is used as this film, it can be preferably used as a medical tape.

[Shape memory member]
The method of using the composite 100 of the present embodiment is not particularly limited, but as described above, the composite 100 of the present embodiment has shape memory ability by including the crosslinked polymer 110 . The composite 100 of the present embodiment can be fixed in a temporary shape by heating to a softening point (a temperature near the melting temperature of crystals) under stress and then cooling. The temporary shaped composite 100 is then reheated to its softening point and returns to its permanent shape. In addition, the composite 100 of the present embodiment includes the metal nanowires 120 (more specifically, the metal nanowires 120 are incorporated in the crosslinked polymer 110), so that local heating due to the application of current It is drivable. Thus, the composite 100 of the present embodiment is suitable for producing a member containing it and using it as an electrically driven shape memory member.

Specifically, it can be used as a member that constitutes devices, instruments, etc. applied to the surface of a living body such as a wearable device, and as a member that constitutes devices, instruments, etc. that are applied in vivo. Alternatively, depending on the desired application, the composite of this embodiment can be used alone or in combination with other members.

The present invention will be described in more detail below based on examples.
The materials, amounts used, proportions, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the examples shown below.

1. Synthesis and Analysis of Curable Compound 1-1.
[Synthesis of curable compound 1 (2b20PCL macromonomer)]
A curable compound 1 (2b20PCL macromonomer) was synthesized according to the following scheme.
First, 1,4-butanediol (2.21 mL, 0.025 mol) as a divalent ring-opening polymerization initiator and ε-caprolactone (CL) (105.6 mL, 1 mol), and Tin (II) as a catalyst 0.2 mL of -2 ethylhexanoate was added to a round-bottomed flask and reacted at 120° C. for 24 hours under nitrogen atmosphere.

After that, the reaction product was reprecipitated in a mixed solvent of hexane and diethyl ether at a volume ratio of 1:1, and dried under reduced pressure to obtain a bibranched 20-mer PCL (hereinafter also referred to as "2b20PCL").

Next, 10 times the amount of acryloyl chloride (17.7 mL, 0.22 mol) and 11 times the amount of triethylamine (33.2 mL, 0.24 mol) relative to the terminal group of the recovered 2b20PCL (50 g, 0.011 mol) was added and allowed to react for 72 hours. Then, it was reprecipitated in methanol for purification and dried under reduced pressure to recover curable compound 1 (2b20PCL macromonomer), which is a macromonomer of 2b20PCL.

The molecular weight of "2b20PCL" and the number of repeating oxyalkylenecarbonyl groups were determined by GPC and ¹ H-NMR. The test conditions are as follows.
The number average molecular weight of 2b20PCL determined from the results of GPC was 3700, and Mw/Mn was 1.23.

・GPC measurement conditions Measurement device: (Tosoh) HLC-8220GPC
Detector: Differential refractive index (RI) detector Column used: "Shodex (trademark)" GPC LF-804 (80 mm ID × 300 mm × 2)
Column temperature: 40°C
Eluent: DMF, flow rate 0.5 mL/min Sample: 0.2% by mass dissolved in DMF, filtered through a 0.45 μm membrane filter Molecular weight standard polymer: Polystyrene (molecular weight = 1970, 3930, 7920, 12140, and , 21030), 0.1% by mass

・ NMR measurement conditions Measuring device: 400 MHz NMR (manufactured by JEOL)
Solvent: deuterated chloroform (CDCl ₃ )
Sample concentration: ~30mg/mL (3mass/vol%)
Reference substance: Tetramethylsilane (TMS)
Measurement method: ¹ H measurement Resonance frequency 400 MHz
Observed spectrum width: 0 ppm to 10 ppm
Accumulation times: 128 times Measurement temperature: Room temperature (20 to 25°C)

1-2.
[Synthesis of curable compound 2 (4b50P (CL-co-DLLA))]
A curable compound 2 (a copolymer composed of CL and d,l-Lactide (DLLA)) was synthesized according to the following scheme.
First, pentaerythritol (343 mg, 0.0025 mol), a tetravalent ring-opening polymerization initiator, ε-caprolactone (32 mL, 0.3 mol), DLLA (14.5 g, 0.2 mol), a catalyst Tin ( II) 0.2 mL of 2-ethylhexanoate was added to a round-bottomed flask and reacted at 140° C. for 24 hours under a nitrogen atmosphere to obtain a 4-branched 50-mer P (CL-co-DLLA). Hereinafter, this is also referred to as "4b50P (CL-co-DLLA)".

After that, 10 times the amount of acryloyl chloride and 11 times the amount of triethylamine were added to the terminal groups and reacted for 72 hours. Thereafter, it is reprecipitated in methanol for purification and dried under reduced pressure to recover curable compound 2 (4b50P (CL-co-DLLA) macromonomer), which is a macromonomer of 4b50P (CL-co-DLLA). did. In the scheme below, the molar ratio of m:n is 6:4.

　The number average molecular weight of 4b50P (CL-co-DLLA) measured by GPC was 9900, and the Mw/Mn was 1.44.

1-3.
[Preparation of cured product]
A composition was prepared using curable compound 1 and curable compound 2, and cured by heating to obtain a cured product. Table 1 is the formulation of the composition.
A total of 500 mg of

curable compounds

1 and 2 and 15 mg of BPO as a radical polymerization initiator (curing agent) (3% by mass/volume with respect to the total of curable compounds) were completely dissolved in 695 μL of xylene to form a composition. got

Next, this composition was dropped onto a glass substrate, sandwiched between another glass substrate via a polytetrafluoroethylene spacer with a thickness of 0.2 mm, and placed in an oven at 80° C. overnight (3 hours or longer). Set aside to cure.
The resulting cured product was thoroughly washed with acetone, shrunk in methanol, and dried under reduced pressure (overnight).

[DSC measurement]
DSC measurement was performed in order to measure the melting peak temperature of the crystals of the obtained cured product and the degree of crystallinity. The DSC measurement was performed using a differential scanning calorimeter "X-DSC 7000" (heat flux type) manufactured by SII. The test conditions are as follows.

Measurement container: Aluminum sample pan (φ6.8mm)
Amount and size of sample: The amount of sample was about 10 mg, and it was cut to fit in the sample pan.

Start temperature: 0°C
Heating rate: 5°C/min
End temperature: 120°C

First, each sample (cured product) was heated from room temperature to 120°C, and when it reached 120°C, it was cooled to -5°C. Next, after the temperature of the sample reached −5° C., the temperature was raised from 0° C. to 120° C. at a rate of 5° C./min, and this DSC curve was acquired.

Table 1 shows the melting peak temperature (Tm) of the crystal read from the obtained DSC curve and the degree of crystallinity. The degree of crystallinity was calculated by calculating the enthalpy (ΔH) from the endothermic peak area, and calculating the degree of crystallinity=(ΔH/142)×100.
Each value was calculated to two decimal places and rounded off.

[Measurement of elastic modulus]
The elastic modulus was calculated from the linear portion of the stress-strain curve obtained by the tensile test. The test piece was a sheet having a length of 17.5±2.5 mm, a width of 5.00±0.90 mm and a thickness of 0.14±0.03 mm. Each value was calculated to two decimal places and rounded off.

It should be noted that the lower the elastic modulus value, the larger the amount of deformation when the same force is applied. Moreover, the larger the value of the breaking strain, the less likely the cured product will break even if it receives a large deformation. From the above, a cured product having both a smaller elastic modulus and a larger breaking strain has a larger deformation rate as a shape memory material.
The "ratio" in Table 1 means the molar ratio of the content of curable compound 2 to the content of curable compound 1 and curable compound 2 in the composition ([curable compound 2]/ [Curable compound 1+Curable compound 2]).

From the results in Table 1, the cured products of Examples 1 to 6 obtained by curing the compositions containing curable compound 1 and curable compound 2 all have crystallinity and can be used as shape memory materials. It had a possible deformation rate. Among them, the cured products of Examples 1 to 5 had a small elastic modulus and a large breaking strain, and a large deformation rate as a shape memory material.

More specifically, the cured products of the compositions of Examples 3 and 4 have a higher crystal melting peak temperature (Tm) than the cured products of the compositions of Examples 1 and 2. The melting peak temperature (Tm) of the crystals of the cured product is lower than the cured product of the composition of 5, and the temperature is also in the range of 37.0 to 45.0 ° C., and it is used for driving in vivo ( ligatures, etc.).

In addition, the cured products of the compositions of Examples 1 and 2 have a lower crystal melting peak temperature (Tm) than the cured product of the composition of Example 3, and the temperature is also 33.0 It was in the range of ~37.0°C, and was more suitable for applications (wearable devices, sutures, etc.) driven on the surface of the body.

In addition, the cured products of the compositions of Examples 1 and 2, which have a crystallinity in the range of 10.0 to 15.5%, have a crystallinity of the cured product compared to the cured product of the composition of Example 3. The melting peak temperature (Tm) is lower, and the temperature is in the range of 33.0 to 37.0 ° C., and it is more suitable for applications driven on the biological surface (wearable devices, sutures, etc.) .

In addition, the cured products of the compositions of Examples 3 and 4, which have a crystallinity in the range of more than 15.5% and 40.0% or less, are compared with the cured products of the compositions of Examples 1 and 2. The crystal melting peak temperature (Tm) of the cured product is higher, and the crystal melting peak temperature (Tm) of the cured product is lower than that of the cured product of the composition of Example 5, and the temperature is also 37.0 to 37.0. It was within the range of 45.0° C., and was more suitable for applications driven in vivo (ligatures, etc.).

2. Synthesis and analysis of metal nanowires 2-1.
[Synthesis of silver nanowires 1]
Silver nanowires were synthesized by the following procedure.
Polyvinylpyrrolidone (PVP) (494 mg, 34 mM), Ethylene glycol (160 mL, 2.9 mM), _CuCl2 (0.43 mg, 4 mM) were added to a round bottom eggplant flask and _AgNO3 (480 mg, 94 mM) was added over 30 minutes. Dripped.
After that, the mixture was stirred for 1 hour to synthesize silver nanowires.

The obtained silver nanowire solution was centrifuged (3500 rpm, 20 min), and after removing the supernatant, it was re-dispersed in ethanol. This operation was repeated three times to refine the silver nanowires and collect the silver nanowires as a product.

2-2.
[Synthesis of silver nanowires 2]
Silver nanowires were synthesized by the following procedure.
Polyvinylpyrrolidone (PVP) (900 mg), Ethylene glycol (150 mL), FeCl ₃ (0.43 mg), AgNO ₃ (600 mg) were added to a round bottom eggplant flask and stirred until dissolved.
After dissolution, the mixture was heated to 110° C. in an oil bath and reacted without stirring for 24 hours to synthesize silver nanowires.

Acetone was added to the resulting silver nanowire solution at a ratio of 1:1, centrifuged (3500 rpm, 15 min), and after removing the supernatant, re-dispersed in ethanol. This operation was repeated three times to refine the silver nanowires and collect the silver nanowires as a product.

2-3.
[Analysis of silver nanowires]
Thermogravimetry (TG) was performed on the silver nanowires synthesized in 2-1 and 2-2 above. The measurement conditions are as follows.

· TG measurement conditions Measurement device: TG / DTA6200 (manufactured by Seiko Instruments Inc.)
Heating rate: 10°C/min
Measurement temperature range: 25 to 600°C
Atmospheric gas: Nitrogen Sample weight (mass): 2.3 mg

As a result, a weight change (mass reduction) of 12% was observed with heating in all samples. From this, it was confirmed that the silver nanowires synthesized in this example were coated with PVP at a mass ratio of 12%.

In addition, SEM observation of the silver nanowires was performed using a scanning electron microscope (manufactured by JEOL Ltd., JCM-500 Neoscope).
FIGS. 2(a) and (b) are SEM images of the silver nanowires synthesized in 2-1 and 2-2 above, respectively. The scale bar in FIG. 2(a) is 5 μm, and the scale bar in FIG. 2(b) is 20 μm.
As shown in FIGS. 2(a) and 2(b), the silver nanowires synthesized in this example had a high aspect ratio. Specifically, the silver nanowires synthesized in 2-2 above have an average minor axis length of about 150 nm, an average major axis length of about 30 μm, and an average aspect ratio of about 200 was calculated.

3. Preparation and analysis of complexes (Part 1)
3-1.
[Preparation of complex 1]
A composite was produced by the following procedure.
20 mg of the silver nanowires synthesized in 2-1 above were dispersed in 4 mL of ethanol to prepare a silver nanowire suspension solution. This silver nanowire suspension solution was cast on a glass substrate, and Ethanol was dried at room temperature to produce a silver nanowire film.

Next, using the curable compound 1 (2b20PCL macromonomer) synthesized in 1-1 above as the curable compound constituting the crosslinked polymer, 500 mg of 2b20PCL macromonomer and 15 mg of BPO as a radical polymerization initiator (curing agent) ( 3% by mass/volume with respect to the above macromonomer) was completely dissolved in 695 μL of xylene to prepare a composition. This composition was dropped onto a silver nanowire film prepared on a glass substrate, and sandwiched between another glass substrate with a 0.2 mm thick polytetrafluoroethylene spacer (4 cm × 4 cm) interposed therebetween. C. overnight (3 hours or more) to cure the 2b20PCL macromonomer to produce a sheet-like composite with a length of 3 cm, a width of 3 cm and a thickness of 0.012 cm.

3-2.
[Preparation of complex 2]
A composite was produced by the following procedure.
A curable compound synthesized in the same manner as in 1-1 above except that pentaerythritol, which is a tetravalent ring-opening polymerization initiator, is used as the ring-opening polymerization initiator (4-branched 50-mer PCL (hereinafter also referred to as “4b50PCL” )), 500 mg of 4b50PCL macromonomer and 15 mg of BPO as a radical polymerization initiator (curing agent) (3% by mass/volume with respect to the macromonomer) are completely dissolved in 695 μL of xylene. to prepare the composition. This composition was dropped onto a glass substrate, sandwiched between another glass substrate with a 0.2 mm thick polytetrafluoroethylene spacer (4 cm x 4 cm) interposed therebetween, and placed overnight in an oven at 80°C. The 4b50PCL macromonomer was allowed to stand (for 3 hours or more) to cure, thereby producing a sheet-shaped cured product having a length of 3 cm, a width of 3 cm, and a thickness of 0.016 cm.

In addition, using 4b50PCL, the composition was prepared in the same manner as in 1-3 above, and the cured product obtained by heating and curing had a melting peak temperature (Tm) of 55.3 ° C., and crystallized. degree was 31.3%.

Here, the prepared cured product was heated to a melting point or higher, and cooled in a state of being stretched 300% in the width direction from the original shape using a tensile tester, thereby fixing the stretched shape.

Next, 11.14 mg of the silver nanowires synthesized in 2-1 above was dispersed in 1 mL of ethanol to prepare a silver nanowire suspension solution. A cycle of uniformly casting 0.1 mL of this silver nanowire suspension solution onto one surface of the cured product in which the stretched shape was fixed and drying was repeated 10 cycles to prepare a composite.

3-3.
[Preparation of complex 3]
A composite was produced by the following procedure.
12.8 mg of the silver nanowires synthesized in 2-1 above were dispersed in 350 μL of DMF to prepare a silver nanowire suspension solution.
To this silver nanowire suspension solution, curable compound 1 (2b20PCL macromonomer) (250 mg) synthesized in 1-1 above, and 7.5 mg of BPO as a radical polymerization initiator (curing agent) (3 mass/volume %) was completely dissolved.
The solution containing the obtained silver nanowires and the 2b20PCL macromonomer was dropped onto a glass substrate, and placed on another glass substrate via a 0.2 mm-thick polytetrafluoroethylene spacer (4 cm × 4 cm). It was sandwiched and left overnight (3 hours or more) in an oven at 80° C. to cure the 2b20PCL macromonomer to produce a sheet-like composite with a length of 3 cm, a width of 3 cm and a thickness of 0.014 cm.

In addition, composites were produced by the same procedure as above, except that the amount of silver nanowires dispersed in DMF was 62 mg and 84.7 mg.

3-4.
[Preparation of complex 4]
A composite was produced by the following procedure.
15 mg of the silver nanowires synthesized in 2-2 above were dispersed in 1 mL of ethanol to prepare a silver nanowire suspension solution. This silver nanowire suspension solution was cast on a glass substrate, and Ethanol was dried at room temperature to produce a silver nanowire film. Here, a rectangular mold made of PDMS (polydimethylsiloxane) (inner dimensions: length 3 cm, width 3 cm, depth 0.37 cm) was placed in advance on the glass substrate, and A silver nanowire suspension solution was cast.

In addition, composites were produced by the same procedure as above, except that the amount of silver nanowires dispersed in Ethanol was 10 mg and 5 mg.

3-5.
[Preparation of complex 5]
A composite was produced by the following procedure.
Using the curable compound 1 (2b20PCL macromonomer) synthesized in 1-1 above, 500 mg of 2b20PCL macromonomer and 15 mg of BPO as a radical polymerization initiator (curing agent) (3 mass / volume% with respect to the macromonomer) was completely dissolved in 695 μL of xylene to prepare a composition. This composition was dropped onto a glass substrate, sandwiched between another glass substrate with a 0.2 mm thick polytetrafluoroethylene spacer (4 cm x 4 cm) interposed therebetween, and placed overnight in an oven at 80°C. The 2b20PCL macromonomer was allowed to stand (for 3 hours or more) to cure, thereby producing a sheet-like cured product having a length of 3 cm, a width of 3 cm, and a thickness of 0.015 cm.

Here, a strip-shaped test piece with a length of 2 cm and a width of 1 cm was cut from the prepared cured product.

Next, 10 mg of the silver nanowires synthesized in 2-2 above were dispersed in 1 mL of ethanol to prepare a silver nanowire suspension solution. 0.05 mL (50 μL) of this silver nanowire suspension solution was uniformly cast on one surface of a test piece cut from the cured product, and the drying cycle was repeated 10 times to prepare a composite.

3-6.
[Preparation of complex 6]
A composite was produced by the following procedure.
Using the curable compound 1 (2b20PCL macromonomer) synthesized in 1-1 above, 500 mg of 2b20PCL macromonomer and 15 mg of BPO as a radical polymerization initiator (curing agent) (3 mass / volume% with respect to the macromonomer) was completely dissolved in 695 μL of xylene to prepare a composition. This composition was dropped onto a glass substrate, sandwiched between another glass substrate with a 0.2 mm thick polytetrafluoroethylene spacer (4 cm x 4 cm) interposed therebetween, and placed overnight in an oven at 80°C. The 2b20PCL macromonomer was allowed to stand (for 3 hours or more) to cure, thereby producing a sheet-like cured product having a length of 3 cm, a width of 3 cm, and a thickness of 0.015 cm.

Here, a strip-shaped test piece with a length of 2 cm and a width of 1 cm is cut from the prepared cured product, heated to the melting point or higher, and cooled while being stretched 100% in the longitudinal direction from the original shape using a tensile tester. This fixed the stretched shape.

Next, 10 mg of the silver nanowires synthesized in 2-2 above were dispersed in 1 mL of ethanol to prepare a silver nanowire suspension solution. 0.05 mL (50 μL) of this silver nanowire suspension solution was uniformly cast on one surface of the test piece having the stretched shape fixed, and the drying cycle was repeated 10 times to prepare a composite. .

[Regarding the procedure for preparing the composite]
Here, the procedures for preparing the composite in 3-1 to 3-6 above can be roughly classified into the following three types.
- Production procedure A: After applying a composition containing a curable compound to a molded body of metal nanowires produced on a support, energy is applied to cure the curable compound.
- Preparation procedure B: A suspension solution of metal nanowires is applied to a cured product prepared by applying a composition containing a curable compound onto a support and curing the curable compound by applying energy.
- Preparation procedure C: After applying a mixed solution containing metal nanowires and a cured product compound onto a support, energy is applied to cure the curable compound.

In addition, in Tables 2 to 5, which will be described later, for the sake of convenience, the symbols A to C of the above production procedures are used to indicate the production procedures of the composites of each example. It should also be noted that hereinafter, the symbols A to C of the above-described fabrication procedures may be used to refer to the fabrication procedures of the composites of each example.

3-7.
[Analysis of Complex]
[TG measurement 1]
The composites prepared in 3-1 and 3-3 above were subjected to thermogravimetry (TG) to calculate the content of silver nanowires in each composite. Table 2 shows the results.
In addition, the measurement conditions are as follows.

· TG measurement conditions Measurement device: TG / DTA6200 (manufactured by Seiko Instruments Inc.)
Heating rate: 10°C/min
Measurement temperature range: 25 to 600°C
Atmospheric gas: Nitrogen Sample weight (mass): 5.3 mg (n = 3)

[Drive test 1 by current application]
A strip-shaped test piece with a length of 3 cm and a width of 0.5 cm was cut from the composite prepared in 3-1 to 3-3 above, heated to the melting point or higher, and stretched 100% in the longitudinal direction with a tensile tester. By cooling in this state, the stretched shape was fixed. In this state, alligator clips were sandwiched between both ends of each test piece in the vertical direction, and a voltage was applied to confirm the presence or absence of recovery to the original shape. Table 2 shows the results.

The results shown in Table 2 suggest that in the case of preparation procedure C, it is difficult to obtain a complex that can be driven by application of an electric current. More specifically, in the production procedure C, a composite with a higher silver nanowire content than in the production procedure A was obtained, but no recovery to the original shape was observed in the driving test.
On the other hand, in the composites obtained by the fabrication procedures A and B, recovery to the original shape was observed in the driving test. In particular, the composite obtained in the preparation procedure A (composite of 3-1) was able to repeat deformation and recovery at least three times by applying a voltage of 0.88 V (applied current 0.12 A). .

This means that in the production of the composite of the present invention, the formation of the crosslinked structure of the crosslinked polymer and the formation of the network structure of the metal nanowires are not simultaneous, and preferably have a time lag. It suggests. In addition, among others, as in the preparation procedure A, after applying a composition containing a curable compound that constitutes a crosslinked polymer to the molded body of metal nanowires in which a network structure is formed, energy is applied to the curable compound. By curing, the metal nanowires are likely to be incorporated into the crosslinked polymer in a dispersed state to the extent that the composite can be driven by local heating due to the application of an electric current. In other words, in the aspect in which the composite of the present invention has a sheet-like shape, if metal nanowires are incorporated into at least one surface of the crosslinked polymer, the composite can be driven by local heating due to the application of an electric current. It is believed that the incorporation of metal nanowires throughout the crosslinked polymer is not an essential requirement.

In addition, in the above 3-1 to which the production procedure A is applied, when the curable compound is cured, the silver nanowire film to which the composition is applied is in a state of being sandwiched between the glass substrates, so a certain pressure is applied. Therefore, it is considered that the incorporation of the metal nanowires into the crosslinked structure of the crosslinked polymer proceeds more efficiently.

FIGS. 3(a) and 3(b) are SEM images of the surface (surface where the silver nanowires are incorporated) and the cross section of the composite prepared in 3-1 above, respectively. The scale bar in FIG. 3(a) is 50 μm, and the scale bar in FIG. 3(b) is 200 μm.
As shown in FIGS. 3(a) and 3(b), in the composite of 3-1, the metal nanowires are dispersed to such an extent that the composite can be driven by local heating by applying an electric current, and the crosslinked polymer confirmed to be incorporated in

Here, a strip-shaped test piece with a length of 3 cm and a width of 0.5 cm was cut from the composite prepared in 3-1 above, and a DC power supply (REGULATED DC POWER SUPPLY LX010-3.5 B TAKASAGO) was used to perform the test. Alligator clips were placed at both longitudinal ends of the strip and the relationship between power and temperature was investigated. As a specific test condition, the current value was increased by 0.5 A and the temperature was plotted while the power was maintained for 15 seconds. As for the temperature range, the test was conducted in the range of 25 to 130°C.

The results are shown in FIG.
FIG. 4 is a graph showing the relationship between power (W) and temperature (° C.) in the composite prepared in 3-1 above.
As shown in FIG. 4, in the composite of 3-1, the temperature increased with an increase in electric power (increase in current value), and when the temperature exceeded about 130° C., the structure of the crosslinked polymer was damaged. confirmed. From this result, it was found that the temperature of the composite can be controlled by adjusting the power (applied current) supplied to the composite.

On the other hand, the composite obtained in the preparation procedure B (the composite of 3-2) exhibits an exothermic behavior when a higher voltage (8 V) is applied than the composite obtained in the preparation procedure A (the composite of 3-1). , and recovery to the original shape was observed. From this, it can be concluded that even by applying (a suspension solution of) metal nanowires to a crosslinked polymer having a crosslinked structure, as in the preparation procedure B, the composite is locally heated by applying an electric current. It may be possible to disperse metal nanowires to the extent that they can drive the body. However, as will be described later, the composite obtained by the preparation procedure B may have a problem regarding structural stability.

[Stability test 1: Stability in permanent shape]
Next, using the composites prepared in 3-3 to 3-5 above, structural stability in a permanent shape was tested.
Regarding the composites 3-3 and 3-4, the content of silver nanowires calculated by thermogravimetry (TG) was 26.7% (see Table 2) and 17.3. Using ±2.5% (see Table 4 below), a strip-shaped test piece of the same size as the composite of 3-5, 2 cm long and 1 cm wide, was cut and subjected to the main test. . The test procedure is as follows.

Each of the three types of test pieces was immersed in a 10 mL sample tube containing 5 mL of ethanol, which is a good solvent for silver nanowires. At this time, no particular change was observed in any of the test pieces by visual observation.
Next, when each sample tube was vibrated to cause agitation, no particular change was observed in the specimens of the 3-3 and 3-4 composites, but the 3-5 composite was visually observed. Detachment of the silver nanowires was observed in the test piece of .
Furthermore, each sample tube was subjected to ultrasonic treatment for 1 minute using an ultrasonic cleaner (US-105, manufactured by SND). No particular change was observed, but in the 3-5 composite test pieces, solvent suspension occurred due to detached silver nanowires.
Table 3 shows the above results.

Here, the change in weight of the test piece before and after being subjected to the stability test 1 described above will be described.
In the specimens of the composites 3-3 and 3-4 in which no detachment of the silver nanowires was observed by visual observation, an increase in weight of about 0.2 to about 0.5 mg was observed before and after the test. was taken. This is believed to be associated with partial residual ethanol, the test solvent.
On the other hand, in the composite test piece of 3-5, in which clear detachment of silver nanowires was observed by visual observation, a weight decrease of about 3 mg was observed before and after the test. The weight was almost the same as the weight after cutting the test piece from the cured product in the production procedure of 3-5 above. That is, in the test piece of the composite of 3-5, it is considered that almost all of the silver nanowires constituting the composite were detached from the crosslinked polymer in the stability test 1 described above. In fact, the appearance of the test piece after the test did not have metallic luster due to silver nanowires, and had the same properties as the permanent shape of the cured product of 2b20PCL macromonomer.

[Stability test 2: Stability in temporary shape]
Next, using the composites prepared in 3-3, 3-4, and 3-6 above, the structural stability in the temporary form was tested.
Regarding the composites of 3-3 and 3-4, a sample having the same silver nanowire content as used in the stability test 1 was used, and the same size as the composite of 3-6, 2 cm in length, was used. , A strip-shaped test piece with a width of 1 cm is cut, heated to the melting point or higher, and cooled while being stretched 100% in the longitudinal direction from the original shape using a tensile tester, so that the stretched shape is fixed. It was used for this test.

Since the test procedure is the same as the stability test 1 described above, detailed description is omitted.
Moreover, the test result was also the same as the stability test 1 mentioned above. Specifically, when each of the above three types of test pieces was immersed in a 10 mL sample tube containing 5 mL of ethanol, which is a good solvent for silver nanowires, no particular change was observed in any of the test pieces by visual observation. I didn't.
Next, when each sample tube was vibrated to cause agitation, no particular change was observed in the specimens of the 3-3 and 3-4 composites, but the 3-6 composite was visually observed. Detachment of the silver nanowires was observed in the test piece of .
Furthermore, each sample tube was subjected to ultrasonic treatment for 1 minute using an ultrasonic cleaner (US-105, manufactured by SND). Although no particular change was observed, in the specimens of composites 3-6, suspension of the solvent due to detached silver nanowires occurred.
Table 3 shows the above results.

Here, the same tendency as in the stability test 1 was observed in the weight change of the test piece before and after being subjected to the stability test 2 described above. Specifically, in the specimens of the composites 3-3 and 3-4, in which no detachment of silver nanowires was observed by visual observation, about 0.1 to about 0.6 mg of Weight gain was observed. This is believed to be associated with partial residual ethanol, the test solvent.
On the other hand, in the composite test piece 3-6, where clear detachment of the silver nanowires was observed by visual observation, a weight decrease of about 1.3 mg was observed before and after the test. The weight of the piece was almost the same as the weight after cutting the test piece from the cured product in the preparation procedure of 3-6 above. That is, in the test piece of the composite of 3-6, it is considered that almost all of the silver nanowires constituting the composite were detached from the crosslinked polymer in the stability test 2 described above. In fact, the appearance of the test piece after the test did not have metallic luster due to silver nanowires, and had the same properties as the temporary shape of the cured product of 2b20PCL macromonomer.

[TG measurement 2]
Next, thermogravimetry (TG) was performed on the composites prepared in 3-4 above, and the content of silver nanowires in each composite was calculated. Table 4 shows the results.
In addition, the measurement conditions are as follows.

· TG measurement conditions Measurement device: TG / DTA6200 (manufactured by Seiko Instruments Inc.)
Heating rate: 10°C/min
Measurement temperature range: 25 to 550°C
Atmospheric gas: Nitrogen Sample weight (mass): 3 mg (n = 2)

[Driving test 2 by current application]
Also, from the composite prepared in 3-4 above, a strip-shaped test piece with a length of 3 cm and a width of 0.5 cm is cut, heated to the melting point or higher, and cooled while being stretched 100% in the longitudinal direction with a tensile tester. This fixed the stretched shape. In this state, alligator clips were sandwiched between both ends of each test piece in the vertical direction, and a voltage was applied to confirm the presence or absence of recovery to the original shape. Table 4 shows the results.

From the results shown in Table 4, it was suggested that a certain amount or more of silver nanowires was necessary in order to obtain a composite that can be driven by applying an electric current, even in the case of fabrication procedure A. In other words, it was suggested that the composite obtained by the preparation procedure A becomes a composite that can be driven by the application of an electric current if the content of silver nanowires in the composite is a certain value or more. The amount of metal nanowires necessary for the production procedure and the content of metal nanowires in the composite are considered to depend on the shape and size of the target composite, but are used in 3-4 above. It is possible to use metal nanowires (silver nanowires) in an amount exceeding at least 5 mg for the inner size of the mold made of PDMS, more specifically, the area of 3 cm long × 3 cm wide (9 cm ² ). , it can be said that a network structure can be formed in which the silver nanowires are dispersed to the extent that the composite can be driven by local heating due to the application of electric current. In addition, in the composite in which the metal nanowires (silver nanowires) having a network structure thus formed are incorporated into the crosslinked structure of the crosslinked polymer, the silver nanowire content is about 5% or more, preferably 10%. It can be said that the above is possible.

FIGS. 5(a) to 5(f) are SEM images of the surfaces of the three types of composites prepared in 3-4 above in permanent shape (before deformation) and temporary shape (after deformation). .
Figures 5(a) to (c) show the surface (the surface where the silver nanowires are incorporated) in the permanent shape (before deformation) of the composites fabricated using 5 mg, 10 mg, and 15 mg of silver nanowires, respectively. It is a figure which shows the SEM image of.
Figures 5(d)-(f) show the surface (side where silver nanowires are incorporated) in the temporary shape (after deformation) of composites fabricated using 5 mg, 10 mg, and 15 mg of silver nanowires, respectively. It is a figure which shows the SEM image of.
The scale bar in FIGS. 5(a), (c), (d) and (e) is 10 μm, the scale bar in FIG. 5(b) is 20 μm, and the scale bar in FIG. 5(f) is 5 μm. is.

As shown in FIGS. 5(a) to 5(c), in the permanent shape (before deformation), three types of composites with different silver nanowire contents (different amounts of silver nanowires used in the preparation of the composites). There was no significant difference in the dispersion state of silver nanowires between
On the other hand, as shown in FIGS. 5(d) to (f), in the temporary shape (after deformation), the silver nanowires in the SEM image of FIG. 5(d) are larger than those in FIGS. It was observed that the state of dispersion (degree of overlapping of silver nanowires) was reduced.

From these results, in order for the composite of the present invention to be driven by the application of electric current, the network structure of the metal nanowires must be maintained to some extent not only in the permanent shape but also in the desired deformed state (temporary shape). It was suggested that this is necessary and that the complex may be drivable by localized heating by the application of an electric current.

[Conductive test]
Next, a strip-shaped test piece with a length of 2 cm and a width of 0.5 cm was cut out from the composite prepared in 3-4 above, alligator clips were sandwiched at both ends of the test piece in the longitudinal direction, and a source meter (2400 SourceMeter, (manufactured by KEITHLEY) was used to measure electrical resistance.
In addition, each test piece was heated to the melting point or higher, stretched 100% in the longitudinal direction by a tensile tester, and then cooled to fix the stretched shape, and the electrical resistance was measured in the same manner.
Further, the stretched shape-fixed test piece was heated to recover the shape, and the electrical resistance was similarly measured. It should be noted that the "heating" is not heating due to the application of electric current because the measurement of electrical resistance during shape recovery is intended here.
Table 5 shows the results.

Also, for comparison, from the composites prepared in 3-3, 3-5 and 3-6 above, the same test pieces were cut and the electrical resistance was measured in the same procedure. As the composite of 3-3, a composite whose content of silver nanowires was calculated to be 26.7% by thermogravimetry (TG) was used. Become.
Table 5 shows the results.

The values of the silver nanowire content of the composites 3-5 and 3-6 in Table 5 are the results of the stability tests 1 and 2 described above, and the heat of the silver nanowires described in 2-3 above. This is an estimated value calculated based on the PVP content (coverage) confirmed by gravimetric measurement (TG).

As shown in Table 5, among the 3-4 composites, the composite that did not recover its shape by applying an electric current (see Table 4) had an electrical resistance of 1.3 ± 0 when its shape was recovered by heating. 0.18 (×10 ⁴ ) (Ω), the electrical resistance of the composite in a permanent shape recovered from a predetermined deformed shape (temporary shape) was 1.0×10 ⁴ Ω. It was suggested that it is preferable to satisfy the following.
In addition, in the temporary shape, the network structure of the metal nanowires is also stretched by stretching the composite, so the electrical resistance of the composite is greater than that in the permanent shape, but is 1.0×10 ⁵ Ω or less. It was suggested that driving by application of electric current is possible if the conditions are satisfied.
In addition, even if the content of metal nanowires in the composite is about the same, there is a difference in electrical resistance between the permanent shape before the initial deformation and the permanent shape after recovery from the temporary shape. I knew I could get This indicates that in the composite of the present invention, the properties of the network structure of the metal nanowires incorporated in the crosslinked structure of the crosslinked polymer (the dispersed state of the metal nanowires) are related to the driving by the application of electric current, and the metal nanowires If the content is in the range of approximately 5% to 25%, more preferably 10% to 25%, the composite is dispersed to the extent that it can be driven by local heating by applying an electric current. is considered possible. Of course, as described above, depending on the application of the composite, the content of metal nanowires may exceed 25%, and the results in Table 5 do not deny it.

On the other hand, in the composite of 3-3, the electrical resistance value could not be measured by the above test because the resistance of the test piece was too high. In Table 5 this is indicated as "N.D.".
In the composites 3-5 and 3-6, the electrical resistance values could be measured in the state after the composites were produced. In addition, in the composite of 3-6, the silver nanowire suspension solution is applied in a state where the cured product of the curable compound 1 that constitutes the crosslinked polymer is stretched during the preparation of the composite. There is no test result corresponding to "before deformation", and the result of "during deformation" corresponds to the content described above. From this, it can be said that in the composite obtained by the preparation procedure B, the metal nanowires can be in a dispersed state at least to the extent that the electrical resistance can be measured.
However, in the composites of 3-5, when the shape of the specimen is changed (in the “during deformation” in Table 5), the layer of silver nanowires peels off (partially detaches) from the layer of crosslinked polymer. was confirmed, and the value of electrical resistance could not be measured. In Table 5 this is indicated as "N.D.". Therefore, for the composite of 3-5, the electrical resistance value at the time of shape recovery by heating was not measured, and the test was terminated.
In addition, in the composite of 3-6, as in the composite of 3-5, when the shape of the test piece was changed (in "recovery" in Table 5), the layer of silver nanowires was peeled off from the layer of the crosslinked polymer. (partial detachment) was confirmed, and the electrical resistance value could not be measured. In Table 5 this is indicated as "N.D.".
These results, and the results of stability tests 1 and 2 described above, suggested that the preparation procedure A was superior in terms of the composite preparation procedure.

4. Preparation and analysis of complexes (Part 2)
4-1.
[Preparation of complex]
A composite was produced by the production procedure A described above.
Specifically, 10 mg of the silver nanowires synthesized in 2-2 above was dispersed in 1 mL of ethanol to prepare a silver nanowire suspension solution (A). This silver nanowire suspension solution (A) was cast on a glass substrate, and Ethanol was dried at room temperature to produce a silver nanowire film. Here, a PDMS rectangular mold (inner dimensions: length 3 cm, width 3 cm, depth 0.37 cm) was placed in advance on the glass substrate, and the silver nanowire suspension solution was placed inside the mold. (A) was cast.

Next, using the curable compound 1 (2b20PCL macromonomer) synthesized in 1-1 above as the curable compound constituting the crosslinked polymer, 500 mg of 2b20PCL macromonomer and 15 mg of BPO as a radical polymerization initiator (curing agent) ( 3% by mass/volume with respect to the above macromonomer) was completely dissolved in 695 μL of xylene to prepare a composition. This composition was dropped onto a silver nanowire film prepared on a glass substrate, and sandwiched between another glass substrate with a 0.5 mm thick polytetrafluoroethylene spacer (4 cm × 4 cm) interposed therebetween. C. overnight (3 hours or longer) to cure the 2b20PCL macromonomer to produce a sheet-like composite with a length of 3 cm, a width of 3 cm and a thickness of 0.031 cm.

Here, in this production example, a silver nanowire suspension solution (B) was also prepared by dispersing 20 mg of the silver nanowires synthesized in 2-2 above in 1 mL of ethanol, and the type and amount of the solution to be cast on the glass substrate (cast By setting the number of times to do) to 4, the content of silver nanowires in the silver nanowire film, that is, the content of silver nanowires in the composite is 10 mg, 20 mg, 30 mg, and 50 mg. made the body. Specifically, the silver nanowire suspension solution (A) is used for the preparation of composites having a silver nanowire content of 10 mg and 20 mg, and the silver nanowire content is 30 mg and 50 mg. used the silver nanowire suspension solution (B). Hereinafter, these complexes are also referred to as "complex 4 (10)," "complex 4 (20)," "complex 4 (30)," and "complex 4 (50)." . As the content of silver nanowires in the silver nanowire film increases, the thickness of the silver nanowire film produced on the glass substrate increases. It was also 3 cm long, 3 cm wide and 0.031 cm thick.

4-2.
[Analysis of Complex]
[DSC measurement]
DSC measurements were performed on Complex 4(10), Complex 4(20), Complex 4(30), and Complex 4(50). The DSC measurement was performed using a differential scanning calorimeter "X-DSC 7000" (heat flux type) manufactured by SII. The test conditions are as follows.

Start temperature: 0°C
Heating rate: 5°C/min
End temperature: 120°C

First, each sample (composite) was heated from room temperature to 120°C, and when it reached 120°C, it was cooled to -5°C. Next, after the temperature of the sample reached −5° C., the temperature was raised from 0° C. to 120° C. at a rate of 5° C./min, and this DSC curve was acquired.

FIG. 6 shows the DSC curves of Complex 4 (10), Complex 4 (20), Complex 4 (30), and Complex 4 (50).
As shown in FIG. 6, an endothermic peak and an exothermic peak in the DSC curve were confirmed in substantially the same temperature range for all composite samples. In addition, although not shown in FIG. 6, a cured product (silver nanowires incorporated) of curable compound 1 (2b20PCL macromonomer) prepared under the same conditions as described in 4-1 above except that silver nanowires were not included An endothermic peak and an exothermic peak were confirmed in substantially the same temperature range as the DSC curve of the above composite also in the DSC curve of the crosslinked polymer that was not coated. From these results, in the procedure for producing the composite of this production example (the above production procedure A), by incorporating the silver nanowires into the cured product (crosslinked polymer) of the curable compound, the melting point of the crosslinked polymer contained in the composite is It was found to have virtually no effect on crystallinity and crystallinity. In other words, in the composite of this production example, it was found that the silver nanowires were incorporated into the crosslinked polymer in a manner capable of maintaining the properties of the crosslinked polymer.

In addition, in the same manner as described with reference to FIGS. 30), and from the SEM images of the surface (the surface in which the silver nanowires are incorporated) and the cross section of the composite 4 (50), in any composite, the silver nanowires are locally heated by the application of an electric current. was incorporated into the crosslinked polymer in such a state that it was dispersed to the extent that it could be driven.

[TG measurement]
Next, thermogravimetry (TG) was performed on Composite 4(10), Composite 4(20), Composite 4(30), and Composite 4(50).
In addition, the measurement conditions are as follows.

FIG. 7 shows the TG curves of Complex 4 (10), Complex 4 (20), Complex 4 (30), and Complex 4 (50).
As shown in FIG. 7 , a certain weight change (mass decrease) was observed with heating in all composite samples, and the greater the silver nanowire content, the higher the mass decrease rate (%). rice field. From these results, in the procedure for producing the composite of this production example (the above-mentioned production procedure A), a suspension solution of metal nanowires having a certain concentration is applied when producing a compact of metal nanowires on a support. It was found that the content of metal nanowires in the composite can be controlled by adjusting the amount (the amount cast onto the support).

From the TG curve shown in FIG. 7, the content of silver nanowires in Composite 4(10), Composite 4(20), Composite 4(30), and Composite 4(50) is 5. .67%, 10.42%, 22.43%, and 31.35%.

[Stability test]
Next, using the composites prepared in 3-3 to 3-6 above using composite 4(10), composite 4(20), composite 4(30), and composite 4(50), Structural stability in permanent and temporary shapes was tested under the same test conditions and procedures as in the previous study.

As a result, no particular changes were observed in the visual observation of any of the composite test pieces, confirming the structural stability of the permanent and temporary shapes.

[Conductive test]
Next, from Composite 4 (10), Composite 4 (20), Composite 4 (30), and Composite 4 (50), a strip-shaped test piece with a length of 3 cm and a width of 0.5 cm was cut and tested. Alligator clips were clamped at both ends of the piece in the longitudinal direction, and electrical resistance was measured using a source meter (2400 SourceMeter, manufactured by KEITHLEY).
In addition, each test piece was heated to the melting point or higher, stretched 100% in the longitudinal direction by a tensile tester, and then cooled to fix the stretched shape, and the electrical resistance was measured in the same manner.
Furthermore, the electrical resistance of each test piece was measured in the same manner when the stretching ratio was set to 200% and 300% with a tensile tester.

As a result, it was confirmed that the test pieces obtained from any of the composites, in the permanent shape and the temporary shape, had electrical conductivity to the extent that electrical resistance could be measured.
In addition, the larger the content of silver nanowires contained in the composite (the higher the content), the higher the rate of stretching with a tensile tester, 100%, 200%, and 300%. rise) was found to be small.
These results suggested that it is effective to set the content of metal nanowires in the composite to a higher value when the shape memory material is intended to be used at a higher deformation rate.

[Drive test 1 by current application]
Next, from Composite 4(10), Composite 4(20), Composite 4(30), and Composite 4(50), a strip-shaped test piece with a length of 3 cm and a width of 0.5 cm was cut, and the melting point was determined. It was heated to the above temperature, stretched 300% in the longitudinal direction by a tensile tester, and then cooled to fix the stretched shape. In this state, alligator clips were sandwiched between both ends of each test piece in the vertical direction, and a voltage of 2.0 V was applied to confirm the state of recovery to the original shape.

As a result, in addition to being able to efficiently maintain the 300% stretched state (temporary shape) of the test piece obtained from any sample (fixation rate > 99%), it was possible to return to the original shape (permanent shape). It was found that the recovery performance was also excellent (recovery rate>90%).

[Driving test 2 by current application]
Next, using the same test piece as in the driving test 1, the cycle of stretching 300% in the longitudinal direction and recovering to the original shape by applying a voltage of 2.0 V was repeated for a total of 20 cycles. The stress induced in the strip and the electrical resistance after each cycle (recovery to the permanent shape) were measured.

Figures 8(a)-(d) show the results for each cycle for specimens obtained from Composite 4(10), Composite 4(20), Composite 4(30), and Composite 4(50), respectively. 1 is a graph showing the stress (MPa) generated in a test piece in relation to the test time (s).
As shown in FIGS. 8(a) to 8(d), it was confirmed that the stress values when the specimens obtained from any of the composites were repeatedly stretched 300% in the longitudinal direction 20 times were almost constant. rice field. This means that all composites are mechanically (structurally) stable against repeated deformation and recovery at least 20 times under the condition of a large deformation rate of 300%. is doing.
Furthermore, the electrical resistance after 1 cycle and the electrical resistance after 20 cycles in each test piece are almost the same, and all composites are mechanically (structurally) resistant to repeated deformation and recovery under the above conditions. It was confirmed that in addition to excellent stability, it is also electrically stable.
In addition, a material that can repeat 300% deformation and recovery at a voltage as low as 2.0 V is an outstanding achievement in comparison with conventional temperature-responsive shape memory materials, and was first demonstrated by the present inventors. It is what was done.

[Drive test 3 by current application]
Next, we conducted a driving test of the complex by contactless power supply using a commercially available wireless power supply device. Specifically, a wireless power feeding experiment kit (manufactured by CQ Publishing Co., Ltd., Tech Village Select Series) was used to assemble an electromagnetic induction type wireless power feeding device having a power transmitting coil and a power receiving coil.
Using the same test piece as in the drive test 1, each test piece was heated to the melting point or higher, and cooled in a state of being stretched 300% in the longitudinal direction with a tensile tester, thereby fixing the stretched shape. In this state, an alligator clip is placed on both ends of each test piece in the vertical direction, the power transmitting coil and the power receiving coil are sufficiently brought close to each other, and an alternating current is passed through the power transmitting coil to generate a magnetic flux in the power receiving coil. The state of recovery to the original shape was confirmed assuming that the current also flowed through the coil.

As a result, it was confirmed that the test piece obtained from each composite recovered from the 300% stretched state (temporary shape) to the original shape (permanent shape), and it was found that it could be driven by the wireless power supply method. rice field.

[Antibacterial test]
Next, using Complex 4(10), Complex 4(20), Complex 4(30) and Complex 4(50), a simple antibacterial test was conducted according to the following procedure.

- Preparation of agar medium 10 mg of high polypeptone, ₂ g of yeast extract, 1 g of _MgSO4.7H2O , 15 g of Agar, and 1 L of distilled water were added to a 1 L beaker and stirred. The beaker was then placed in an autoclave set at 120° C. for 20 minutes to dissolve the solutes and sterilize the solution. After taking out the beaker and pouring 20 mL of the resulting solution into a 90 mm dish, it was cooled to prepare an agar medium.

・Test 1 (test in permanent shape)
Staphylococcus aureus (1.0×10 ⁸ CFU/mL) was spread on the prepared agar medium.
As a specimen, a circular test piece with a diameter of 1 cm was cut from each composite and sterilized with ethylene oxide gas (EOG). ) was placed in contact with the agar medium. After that, the cells were incubated for 2 days in an incubator set at 30° C., and the presence or absence and width of growth inhibition zones (halos) were evaluated. As a control, a cured product of curable compound 1 (2b20PCL macromonomer) prepared under the same conditions as described in 4-1 above except that silver nanowires were not included (crosslinked polymer in which silver nanowires were not incorporated). A similar test was performed using

As a result, no halo was observed in the control crosslinked polymer, whereas the halos obtained from Composite 4 (10), In the test piece (specimen), the more silver nanowires contained in the composite (the higher the content), the more halos were observed. More specifically, complex 4 (20) clearly showed an increase in the number of halos compared to complex 4 (10), and complex 4 (30) tested more than complex 4 (20). More halos were seen over a wider area of the specimen, and even more halos were seen throughout the specimen for Composite 4 (50). In addition, complex 4 (50) also tended to have wider individual halos.

・Test 2 (test with temporary shape)
Staphylococcus aureus (1.0×10 ⁸ CFU/mL) was spread on the agar medium prepared by the above method.
As a specimen, the complex 4 (50) was stretched 300% in a certain direction and cooled, and a strip-shaped test piece of 1 cm long and 0.5 cm wide was cut from the stretched shape fixed and sterilized by EOG. After that, the surface on which the silver nanowires were incorporated (the surface on which the silver nanowire film was located when the composite was produced) was placed in contact with the agar medium. Then, it was incubated for 2 days in an incubator set at 30° C., and the presence or absence and width of halos were evaluated. As a control, the same test was conducted using the crosslinked polymer described above.

As a result, in the control crosslinked polymer, no halo was observed even in the temporary form as in Test 1 (permanent form test) described above, whereas the specimen obtained from Composite 4 (50) ( Specimen), even in the temporary shape, almost the same number and width of halos were found throughout the specimen as in the permanent shape of Test 1. From these results, the composite of the present invention, both in its permanent form and in its temporary form, has the properties originally possessed by the metal nanowires (when the metal nanowires are silver nanowires, the properties may be antibacterial). can be effectively demonstrated.

The composite of the present invention can be applied to a shape-memory member that has a shape-memory ability and can be driven by local heating by applying an electric current. Therefore, it can be applied to a wider range of applications than conventional temperature-responsive shape memory materials. Specifically, for example, by adjusting the melting peak temperature of the crosslinked polymer in consideration of the temperature on the surface of the living body and/or the temperature in the living body, it is possible to apply the material to the living body, which has been difficult with conventional temperature-responsive shape memory materials. It can be applied, and it is expected to be applied to minimally invasive medical devices etc. as an electrically driven shape memory member.

100 Composite 110 Crosslinked Polymer 120 Metal Nanowire

Claims

a crosslinked polymer having an endothermic peak when differential scanning calorimetry (DSC) is performed;
metal nanowires;
A complex containing
In the conductivity test, at least in the state before deformation and in the state of being deformed by 100% or more in a predetermined direction by applying stress from the outside, it has conductivity to the extent that the electrical resistance can be measured, and
In a stability test using a good solvent for the crosslinked polymer and/or the metal nanowires, substantially no detachment of the metal nanowires occurs.
Complex.
The crosslinked polymer is a cured product of a curable compound 1 represented by the following formula 1, a cured product of a curable compound 2 represented by the following formula 2, and the curable compound 1 and the curable compound 2 2. The composite according to claim 1, selected from the group consisting of a cured product of a composite of a curable compound consisting of:

(In formula 1, L 1 represents a poly(oxyalkylenecarbonyl) group, X 1 represents a group having a curable group, R 1 is a hydrogen atom, or a monovalent substituent having no curable group group, q1 represents an integer of 2 or more, p1 represents an integer of 0 or more, and when q1 is 2 and p1 is 0, M1 represents a single bond or a divalent group, and q1 represents 2 and when p1 is 1 or more and q1 is 3 or more, M 1 represents a p1+q1-valent group, and multiple R 1 and L 1 may be the same or different)

(In Formula 2 , L2 represents a polymer chain, and the polymer chain includes repeating units consisting of an oxyalkylenecarbonyl group, repeating units derived from D-lactic acid, and repeating units derived from L-lactic acid. X 2 represents a group having the same curable group as that of X 1 in Formula 1, and R 2 represents a hydrogen atom or a monovalent substituent having no curable group , q2 represents an integer of 2 or more, p2 represents an integer of 0 or more, when q2 is 2 and p2 is 0, M2 represents a single bond or a divalent group, q2 is 2 and p2 is When 1 or more and when q2 is 3 or more, M 2 represents a p2 + q divalent group, and multiple R 2 and L 2 may be the same or different)
The composite according to claim 1 or 2, wherein the metal nanowires are silver nanowires.
The composite according to any one of claims 1 to 3, wherein the content of the metal nanowires calculated by thermogravimetry (TG) is 5% or more and 60% or less.
A shape memory member comprising the composite according to any one of claims 1 to 4.
A method for producing the composite according to any one of claims 1 to 4,
A step of producing a molded body containing metal nanowires;
applying a composition containing a curable compound to the molded body;
a step of applying energy to the molded article to which the composition is applied to cure the curable compound;
A method, including
The method according to claim 6, wherein the application of energy is performed by heating the compact.
The method according to claim 6 or 7, wherein the application of energy is performed under pressurized conditions.
The curable compound is a curable compound 1 represented by the following formula 1, a curable compound 2 represented by the following formula 2, and a curing composed of the curable compound 1 and the curable compound 2 A method according to any one of claims 6 to 8, wherein the conjugate is selected from the group consisting of complexes of sexual compounds.

(In formula 1, L 1 represents a poly(oxyalkylenecarbonyl) group, X 1 represents a group having a curable group, R 1 is a hydrogen atom, or a monovalent substituent having no curable group group, q1 represents an integer of 2 or more, p1 represents an integer of 0 or more, and when q1 is 2 and p1 is 0, M1 represents a single bond or a divalent group, and q1 represents 2 and when p1 is 1 or more and q1 is 3 or more, M 1 represents a p1+q1-valent group, and multiple R 1 and L 1 may be the same or different)

(In Formula 2 , L2 represents a polymer chain, and the polymer chain includes repeating units consisting of an oxyalkylenecarbonyl group, repeating units derived from D-lactic acid, and repeating units derived from L-lactic acid. X 2 represents a group having the same curable group as that of X 1 in Formula 1, and R 2 represents a hydrogen atom or a monovalent substituent having no curable group , q2 represents an integer of 2 or more, p2 represents an integer of 0 or more, when q2 is 2 and p2 is 0, M2 represents a single bond or a divalent group, q2 is 2 and p2 is When 1 or more and when q2 is 3 or more, M 2 represents a p2 + q divalent group, and multiple R 2 and L 2 may be the same or different)