JP6621231B2 - Light transmittance adjusting material having an autonomous resilience improving function, manufacturing method, usage method and repair method of light transmittance adjusting material having an auto resilience improving function - Google Patents

Description

  The present invention relates to a light transmittance adjusting material having an autonomous restoring property improving function, a manufacturing method, a using method, and a repairing method of the light transmittance adjusting material having an autonomous restoring property improving function.

  Regarding the gel material, the present inventor has already proposed the one shown in Patent Document 1. The gel material according to Patent Document 1 contains a fine particle and a photoresponsive material in a liquid crystal material, and photo-isomerizes the photoresponsive material by light irradiation, thereby causing phase transition of the liquid crystal material to form a sol, gel The state is realized. In this gel material, when the gel is developed, when the fine particles that are uniformly dispersed in the isotropic phase undergo a phase transition from the isotropic phase to the liquid crystal phase, the liquid crystal It is discharged from the phase region and aggregates in the isotropic phase region to construct a network structure. Regarding the hardness of the gel, it is possible to ensure a hardness of a predetermined level or more. For this reason, the said gel material can be utilized as what comprises a member surface under a gel state.

  By the way, when utilizing the said gel material as what comprises the member surface, it is preferable that it can restore autonomously with respect to external force deformation from the outside.

JP 2013-144769 A

  However, the gel material has a storage elastic modulus in a gel state that can ensure a value equal to or higher than a predetermined value, but exhibits a plastic deformation characteristic with respect to an external force and cannot sufficiently enhance the elastic deformation characteristic. For this reason, autonomous restoration (self-repair) with respect to external force deformation from the outside is not necessarily in a sufficiently satisfactory state.

This invention is made | formed in view of the said situation, The 1st objective is to provide the gel material which can improve autonomous restoration | restoration.
The second object is to provide a method for producing a gel material for producing the gel material.
The third object is to provide a method of using the gel material using the gel material.
A fourth object is to provide a method for repairing a gel material for repairing the gel material.

In order to achieve the first object of the present invention (the invention according to claim 1),
A light transmittance adjusting material having an autonomous resilience improving function, comprising a photoresponsive liquid crystal material that is photoisomerized by light irradiation and a polymer-modified fine particle having a surface grafted with a polymer having a molecular weight of 40000 or more. ,
The photoresponsive liquid crystal material is photoisomerized by irradiating the light transmittance adjusting material with light, and the liquid crystal phase-isotropic phase transition temperature of the light transmittance adjusting material is the use temperature of the light transmittance adjusting material. A phase transition from a liquid crystal phase to an isotropic phase by changing from above to below the use temperature, or a liquid crystal phase-isotropic phase transition temperature of the light transmittance adjusting material is the light transmittance. Those that cause a phase transition from the isotropic phase to the liquid crystal phase by changing from below the use temperature to above the use temperature is used,
As the polymer, in any of the post before the light irradiation and the light irradiation also, phase separation relative to the photo-responsive liquid crystal material of the polymer modified fine particles - compatible transition temperature, the crystal phase - from isotropic phase transition temperature The higher one is used,
The phase separation-phase transition temperature is adjusted to be higher than the use temperature of the light transmittance adjusting material both before and after light irradiation, and at the use temperature, the photoresponse the polymer modified fine particles are configured to have a phase-separated state with respect to gender liquid crystal material. Preferred embodiments of claim 1 are as described in claims 2 to 5.

In order to achieve the second object of the present invention (the invention according to claim 6),
Light transmittance having a function of improving the self-recoverability by mixing a photoresponsive liquid crystal material that is photoisomerized by light irradiation and polymer-modified fine particles grafted with a polymer having a molecular weight of 40000 or more on the surface. A method for manufacturing the adjusting material,
The photoresponsive liquid crystal material is photoisomerized by irradiating the light transmittance adjusting material with light, and the liquid crystal phase-isotropic phase transition temperature of the light transmittance adjusting material is the use temperature of the light transmittance adjusting material. A phase transition from a liquid crystal phase to an isotropic phase by changing from above to below the use temperature, or a liquid crystal phase-isotropic phase transition temperature of the light transmittance adjusting material is the light transmittance. Using what causes a phase transition from the isotropic phase to the liquid crystal phase by changing from below the use temperature of the adjustment material to above the use temperature,
As the polymer, in any of the post before the light irradiation and the light irradiation also, phase separation relative to the photo-responsive liquid crystal material of the polymer modified fine particles - compatible transition temperature, the crystal phase - from isotropic phase transition temperature Use a higher one,
As the mixture, a composition in which the phase separation-solvent transition temperature is higher than the use temperature of the light transmittance adjusting material both before and after light irradiation is used .

In order to achieve the third object of the present invention (the invention according to claim 7),
A member is configured using the light transmittance adjusting material according to claim 1 ,
When increasing the light transmittance of the member, the member is irradiated with light to cause the photoresponsive liquid crystal material in the member to phase change to an isotropic phase,
When reducing the light transmittance of the member, the member is irradiated with light to cause the photoresponsive liquid crystal material in the member to undergo a phase transition to a liquid crystal phase .
It is set as the structure used as the usage method of the light transmittance adjusting material which also has the autonomous restoring property improvement function characterized by this.
In order to achieve the fourth object of the present invention (the invention according to claim 8),
When the surface of the member comprised using the light transmittance adjusting material according to claim 1 is damaged, the damaged part of the member is irradiated with light and heated to produce the photoresponsive liquid crystal. The material is transferred to an isotropic phase, and the polymer-modified fine particles are in a compatible state with the photoresponsive liquid crystal material to repair a damaged portion of the member.
It is set as the structure used as the restoration | repair method of the light transmittance adjusting material which also has the autonomous restoring property improvement function characterized by this.

  According to the present invention (the invention according to claim 1), since the photoresponsive liquid crystal material contains fine particles whose polymer is chemically modified on the surface, each fine particle is treated with the photoresponsive liquid crystal. The polymer of each fine particle can be entangled with each other while the photoresponsive liquid crystal material is in an isotropic phase and the polymer-modified fine particle (the polymer is a fine particle) can be dispersed in the material. When the surface is chemically separated), the phase separation of the polymer-modified fine particles increases as the liquid crystal phase-isotropic phase transition temperature is approached. The formation of a network-like structure is promoted. For this reason, unlike simple particle aggregation, the storage elastic modulus (dynamic viscoelasticity) can be increased to increase the elastic limit, and autonomous restoration (self-repair) against external force deformation from the outside can be improved. be able to. In particular, when the gel material is in a liquid crystal phase, a storage elastic modulus under the liquid crystal phase can be added, and the elastic limit can be further increased. For this reason, autonomous restoration can be remarkably improved by using the light transmittance adjusting material (gel material) under the liquid crystal phase.

Further, as the polymer, in any of the post before the light irradiation and the light irradiation also, phase separation relative to the photo-responsive liquid crystal material of the polymer modified fine particles - compatible transition temperature, the crystal phase - isotropic phase transition temperature which is higher is used than the phase separation - compatible transition temperature, in any of the before and after light irradiation and light irradiation also have been adjusted to be a temperature higher than the operating temperature of the light transmittance adjusting member Te, wherein the operating temperature has become the polymeric modifying particles and phase separation with respect to the photo-responsive liquid crystal material, moreover, before the light irradiation, photo-responsive liquid crystal material is in the state of the liquid crystal phase, and When the photoresponsive liquid crystal material changes state with light irradiation from the state before light irradiation , the photoresponsive liquid crystal material is in an isotropic phase state, thus maintaining a hard gel state. However, photoisomerization reaction by light irradiation It is possible to adjust the light transmittance to use.
That is, when the light- responsive liquid crystal material is in a liquid crystal phase state before light irradiation and the state of the light-responsive liquid crystal material changes with light irradiation from the state before light irradiation , the light-responsive liquid crystal material is Since it is in an isotropic phase, the light- responsive liquid crystal material becomes a liquid crystal phase before light irradiation , and its light transmittance is lowered (opaque state), while light When the photoresponsive liquid crystal material undergoes a phase transition from the liquid crystal phase to the isotropic phase by the photoisomerization reaction by irradiation, the light transmittance increases (transparent state), and the photoresponsive liquid crystal material changes from the isotropic phase to the liquid crystal phase. When the phase transition is performed, the light transmittance decreases again (modulation of optical characteristics). Moreover, before the light irradiation, when the polymer modified fine particles is in a phase separated state with respect to photo-responsive liquid crystal material and photo-responsive liquid crystal material changes state along with the light emitted from the front light irradiation state, Since the polymer-modified fine particles are in a phase-separated state with respect to the photoresponsive liquid crystal material, the hard gel state (solid state) can be maintained under any region regardless of the phase transition. For this reason, light transmittance can be adjusted, maintaining a hard gel state.
Furthermore, since the molecular weight of the polymer is 40,000 or more, a stable gel state can be obtained. Here, the molecular weight of the polymer is set to “40000 or more” because, based on the knowledge of the present inventors, when the molecular weight is less than 40000, the elastic modulus is lowered and it is difficult to form a gel.
Therefore, in the present invention, as a material of the gel material, the light transmission can remarkably improve the autonomous restoration and can maintain the hard gel state (solid state) under any region of the phase structure. Rate adjustment material can be provided.

According to the invention of claim 2, since the polymer-modified fine particles are contained in an amount of 5 wt% or more based on the photoresponsive liquid crystal material, the fine particles are uniformly dispersed in the photoresponsive liquid crystal material. The entanglement between each other can be performed smoothly, and the gel material can be reliably made into a gel. Here, “5 wt% or more” is based on the knowledge of the present inventor because “less than 5 wt%” makes it difficult to form a gel.

According to the invention of claim 3, the photoresponsive liquid crystal material is liquid crystal material and photoisomerized by light irradiation to change the liquid crystal material from the liquid crystal phase to the isotropic phase, or from the isotropic phase to the liquid crystal phase. Since it is a mixture with a photoresponsive material that undergoes phase transition, a desired one can be selected from many types of liquid crystal materials and many photoresponsive materials. The degree of freedom of selection can be increased as compared with those indicating.
According to the invention of claim 4, when the light transmittance adjusting material is used at a certain temperature, the use temperature of the light transmittance adjusting material is higher than the phase separation-phase transition temperature before light irradiation. -Since the concentration of the photoresponsive material is adjusted so that the temperature is close to the isotropic phase transition temperature, the light transmittance adjusting material is a region close to the liquid crystal phase in the isotropic phase ( Even if a phase transition from the non-light-irradiated state to the isotropic phase is performed by light irradiation using the fact that it exhibits the largest storage elastic modulus in the liquid crystal phase-isotropic phase transition temperature) It is possible to suppress as much as possible that the storage elastic modulus in is greatly reduced with respect to the storage elastic modulus in the liquid crystal phase. For this reason, even if light modulation is performed by causing phase transition between the liquid crystal phase and the isotropic phase by light irradiation, it is possible to suppress a significant change in the hardness of the gel, and the optical properties without changing the gel hardness so much. Only the characteristics can be changed.

  According to the invention according to claim 5, since it is used as a coating material or a base material itself to be coated on the surface of the base material, the function and effect described in the first to fourth aspects can be exhibited. High performance materials can be provided as the material itself.

According to the invention of claim 6, an autonomously generating mixture by mixing a photoresponsive liquid crystal material that is photoisomerized by light irradiation and polymer-modified fine particles grafted with a polymer having a molecular weight of 40000 or more on the surface. A method for manufacturing a light transmittance adjusting material having a function of improving the resilience, wherein the light responsive liquid crystal material is photoisomerized by irradiating light to the light transmittance adjusting material, and the light transmittance adjusting material The liquid crystal phase-isotropic phase transition temperature changes from above the use temperature of the light transmittance adjusting material to below the use temperature, thereby causing a phase transition from the liquid crystal phase to the isotropic phase, or the light The liquid crystal phase-isotropic phase transition temperature of the transmittance adjusting material changes from below the use temperature of the light transmittance adjusting material to above the use temperature, thereby causing a phase transition from the isotropic phase to the liquid crystal phase. using things, as the polymer, In either after irradiation before and light irradiation also, phase separation relative to the photo-responsive liquid crystal material of the polymer modified fine particles - compatible transition temperature, the crystal phase - using what higher than isotropic phase transition temperature , as the mixture, the phase separation - compatible transition temperature, in any of the before and after light irradiation and light irradiation also, from using those having a high temperature than the operating temperature of the light transmittance adjusting member, according to claim 1 The light transmittance adjusting material according to the above can be manufactured.

According to the invention which concerns on Claim 7, when a member is comprised using the light transmittance adjusting material of Claim 1 , and the light transmittance of the member is raised, the light in this member is irradiated by light irradiation to this member. When the responsive liquid crystal material is phase-transitioned into the isotropic phase and the light transmittance of the member is lowered, the light-responsive liquid crystal material in the member is phase-transitioned into the liquid crystal phase by light irradiation on the member. The light transmittance of the member can be easily adjusted using the phase transition between the isotropic phase based on the liquid crystal phase and the liquid crystal phase, and the light transmittance adjusting material according to claim 1 is used as the light transmittance adjusting material. Therefore, even if a phase transition is performed by light irradiation, a hard gel state (solid state) can be obtained under any state. For this reason, in the usage method of the said light transmittance adjusting material, light transmittance can be adjusted under a hard gel state.

According to the invention which concerns on Claim 8, when the surface of the member comprised using the light transmittance adjusting material described in Claim 1 is damaged, light irradiation and heating are performed with respect to the damaged part of the said member. The photoresponsive liquid crystal material is transferred to an isotropic phase, and the polymer-modified fine particles are in a compatible state with the photoresponsive liquid crystal material. Since the light transmittance adjusting material is restored, the photoresponsive liquid crystal material is in an isotropic phase and the polymer-modified fine particles are in a phase-separated state due to a state change accompanying light irradiation, but the damaged portion is not damaged. Based on the heating, the polymer-modified fine particles shift from the phase separation state to the compatible state, and when the surface of the member is damaged (breaking or the like), the damaged portion can be repaired as a sol. If the repaired part is left after this repair, the temperature of the repaired part is lowered, the photoresponsive liquid crystal material is in an isotropic phase, and the polymer-modified fine particles are in a phase-separated state, returning to a hard gel. For this reason, in the method for repairing the light transmittance adjusting material, when the surface of the member is damaged (breakage or the like), the damaged portion of the member can be regenerated.

Explanatory drawing explaining how the gel material which concerns on embodiment changes a state with a temperature change. Explanatory drawing explaining the change of phase transition temperature _TLC-I accompanying the increase in the 1st form (cis body) density | concentration accompanying light irradiation. The characteristic view which shows the dynamic viscoelastic characteristic accompanying the temperature change about the gel material (polymer / liquid crystal composite gel material 1) which concerns on embodiment. The characteristic view which shows the dynamic viscoelastic characteristic with a temperature change about the gel material (polymer / liquid crystal composite gel material 2) which concerns on embodiment. Explanatory drawing explaining how fine particle density | concentration influences a dynamic viscoelastic characteristic in the gel material (polymer / liquid crystal composite gel material 2) which concerns on embodiment. Explanatory drawing explaining how the molecular weight of a polymer influences a dynamic viscoelastic characteristic in the gel material (polymer / liquid crystal composite gel material 2) which concerns on embodiment. The photograph figure which shows the optical characteristic accompanying the temperature change about the gel material (polymer / liquid crystal composite gel material 2) which concerns on embodiment. As for the gel material (polymer / liquid crystal composite gel material 1) according to the embodiment, how the change (mol%) in the photoresponsive material affects the phase transition temperature _TLC-I and the transition temperature _TIG-IS. Explanatory drawing explaining whether it exerts. Explanatory drawing explaining what area | region A1 is under the density | concentration (mol%) of photoresponsive material, phase transition temperature _TLC-I, and transition temperature _TIG-IS . Explanatory drawing explaining what area | region A2 is under the density | concentration (mol%) of photoresponsive material, phase transition temperature _TLC-I, and transition temperature _TIG-IS . Explanatory drawing explaining what area | region A3 is under the density | concentration (mol%) of photoresponsive material, phase transition temperature _TLC-I, and transition temperature _TIG-IS . Explanatory drawing which shows the dynamic response sol-gel transition characteristic about the gel material which concerns on embodiment. The photograph figure which shows the result of the autonomous restoration (autonomous damage repair) experiment about the gel material (polymer / liquid crystal composite gel material 1) which concerns on embodiment. The photograph figure which shows the result of the optical characteristic experiment accompanying the optical response change about the gel material (polymer / liquid crystal composite gel material 1) which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described.
1. About Gel Material The gel material according to the present embodiment is composed of a mixture of a photoresponsive liquid crystal material and fine particles in which a polymer is chemically modified. This gel material exhibits an autonomous restoration function based on the entanglement of polymers in each fine particle in the gel state, and further exhibits a function of adjusting light transmittance under the hard gel state.

(1) Photoresponsive liquid crystal material
(i) The photoresponsive liquid crystal material plays a role of phase transition between a liquid crystal phase and an isotropic phase by light irradiation as a main material of the gel material according to the present embodiment. As shown in FIG. 1, the photoresponsive liquid crystal material has a liquid crystal phase-isotropic phase transition temperature (hereinafter referred to as phase transition temperature) T _LC-I as a phase transition reference temperature between the liquid crystal phase and the isotropic phase. When the temperature (use temperature) of the photoresponsive liquid crystal material is lower than the phase transition temperature _TLC-I , the photoresponsive liquid crystal material becomes a liquid crystal phase and the temperature of the photoresponsive liquid crystal material (use temperature) ) Is higher than the phase transition temperature _TLC-I , the photoresponsive liquid crystal material is in an isotropic phase.
In this photoresponsive liquid crystal material, first and second forms are respectively generated by photoisomerization based on two different kinds of first and second irradiation lights. The density (ratio) of the first form and the density (ratio) of the second form are in a relative relationship. If the density of the first form increases, the density of the second form decreases. It has become. Among these, the 1st form has the function to reduce phase transition temperature _TLC-I as the density | concentration increases as a state change participating element, as shown in FIG. For this reason, in the state in which the photoresponsive liquid crystal material is in the liquid crystal phase, the phase transition temperature _TLC-I is lowered by the increase in the concentration of the first form based on the first irradiation light, and the photoresponsive liquid crystal material When the temperature (working temperature) becomes higher than the phase transition temperature _TLC-I , the phase transitions to an isotropic phase (see FIG. 2).

  (ii) As the above-mentioned photoresponsive liquid crystal material, a single photoresponsive liquid crystal material that exhibits single photoresponsiveness and liquid crystallinity, or a mixture type photoresponsive material composed of a mixture of a photoresponsive material and a liquid crystal material. Any of the functional liquid crystal materials can be used.

(ii-1) As the single-type photoresponsive liquid crystal material, a photoresponsive material exhibiting liquid crystallinity can be used. For example, an azobenzene compound in which at least one of both ends of the azobenzene skeleton is substituted with an alkyl group or an alkoxy group and the other is substituted with an alkyl group, an alkoxy group, a cyano group, or the like can be used. This single-type photoresponsive liquid crystal material itself is photoisomerized into first and second forms based on two different types of first and second irradiation lights, respectively. The phase transition temperature _TLC-I of the single photoresponsive liquid crystal material changes depending on the concentration of the form. The phase state (liquid crystal phase or isotropic phase) is determined depending on whether the use temperature of the single-type photoresponsive liquid crystal material is lower or higher than the phase transition temperature _TLC-I . .

(ii-2) On the other hand, in the mixture-type photoresponsive liquid crystal material, the photoresponsive material contained therein includes first and second forms based on two different types of first and second irradiation lights. The phase transition temperature _TLC-I of the mixture type photoresponsive liquid crystal material changes depending on the concentrations of the first and second forms. The phase state (liquid crystal phase or isotropic phase) is determined depending on whether the use temperature of the mixture type photoresponsive liquid crystal material is lower or higher than the phase transition temperature _TLC-I . . Therefore, in such a mixture-type photoresponsive liquid crystal material, as is well known, as a photoresponsive material, the basic skeleton structure has, for example, an azobenzene structure, a spiropyran structure, a fulgide structure, a diarylethene structure, a salicylideneaniline. Structures, anthracene structures, norbornadiene structures, cinnamoyl structures, nitrone structures, benzaldoxime structures, stilbene structures, retinal structures, or azomethine structures can be used, and among them, cis-trans isomerization can be performed by light irradiation. An azobenzene structure causing a structural change, a spiropyran structure, a fulgide structure, or a diarylethene structure causing a ring-opening-ring-closing structural change by light irradiation is preferable. The liquid crystal material in the mixture type photoresponsive liquid crystal material may be any material as long as it undergoes phase transition by photoisomerization of the photoresponsive material. In particular, low molecular liquid crystals having terphenyl, phenylbenzoate, tolane, etc. known in the liquid crystal field such as biphenyl are suitable. From the viewpoint of the liquid crystal phase structure, all liquid crystal phases that have been discovered so far are suitable. Among them, nematic phase, smectic phase, discotic phase, cubic phase, and cholesteric phase are particularly preferable. As described above, in this mixture type photoresponsive liquid crystal material, a desired one can be selected from many types of liquid crystal materials and many photoresponsive materials. The degree of freedom of selection can be increased as compared with those showing the above.

(iii) As a first form of the photoresponsive material in the single type photoresponsive liquid crystal material or the mixture type photoresponsive liquid crystal material, the state of the liquid crystal phase of each photoresponsive liquid crystal material is disturbed. In this embodiment, a cis isomer having a bent molecular shape is used, in which a photoresponsive liquid crystal material undergoes a phase transition to an isotropic phase (a shape that affects liquid crystal alignment and physical properties). It has been.
As a second form of the photoresponsive material in the single-type photoresponsive liquid crystal material or the mixture type photoresponsive liquid crystal material, a form in which each photoresponsive liquid crystal material undergoes a phase transition to a liquid crystal phase (liquid crystal alignment or In this embodiment, a trans form having a rod-like molecular shape is used.
As a result, the photoresponsive material in the single type photoresponsive liquid crystal material or the mixture type photoresponsive liquid crystal material is photoisomerized into a cis isomer, and the phase transition temperature T _LC-I based on the concentration of the cis isomer is obtained. When the use temperature of the photoresponsive liquid crystal material exceeds, when the photoresponsive liquid crystal material is in a liquid crystal phase, the liquid crystal phase becomes unstable and transitions to an isotropic phase. On the other hand, the photo-responsive material in a single-type photo-responsive liquid crystal material or a mixture-type photo-responsive liquid crystal material is photoisomerized to a trans isomer to reduce the cis isomer concentration, and the phase transition based on the cis isomer concentration When the use temperature of the photoresponsive liquid crystal material is lower than the temperature TLC _-I , when each photoresponsive liquid crystal material is in an isotropic phase, the isotropic phase is transferred to the liquid crystal phase (photoresponse Control of phase structure of liquid crystalline material).

(iv) With respect to the first and second irradiation light irradiated to the photoresponsive liquid crystal material (single type or mixture type photoresponsive liquid crystal material), as described above, the first irradiation light is The photoresponsive material of the single type photoresponsive liquid crystal material or the mixture type photoresponsive liquid crystal material is changed to the first mode (disturbing the liquid crystal phase state of the liquid crystal material, and the liquid crystal material is led to the isotropic phase. The second irradiating light is a single-type photoresponsive liquid crystal material or a mixture type photoresponsive liquid crystal material photoresponsive material. It has a function of photoisomerizing into the second form (form in which the liquid crystal material is led to a liquid crystal phase, more specifically, a trans form). Therefore, for the first and second irradiation light, ultraviolet light, visible light, near-infrared light, etc., depending on the photoresponsive material of the single type photoresponsive liquid crystal material or the mixture type photoresponsive liquid crystal material It selects suitably from any of these. Among these, a wavelength of 254 to 1064 nm is preferable, and a wavelength of 365 to 632 nm is more preferable. This is because 254 to 1064 nm is a wavelength that can be used with a commercially available general light source, and 365 to 632 nm is a wavelength that can be used with a more versatile light source (mercury lamp, argon ion laser, helium-neon laser).
In the present embodiment, ultraviolet light is used as the first irradiation light, and visible light is used as the second irradiation light. The reason for using such irradiated light is that it is possible to photoisomerize the trans isomer to the cis isomer by ultraviolet light, and to efficiently photoisomerize the cis isomer to the trans isomer by visible light. is there.

(v) The intensity of the first and second irradiation light is appropriately selected according to the photoresponsive material of a single type photoresponsive liquid crystal material or a mixture type photoresponsive liquid crystal material, and its concentration. Among these, 0.2 mW / cm ² or more is preferable. This is because if it is less than 0.2 mW / cm ² , a photoisomerization reaction sufficient to cause phase transition of the liquid crystal material cannot be induced. On the other hand, the upper limit of the intensity of the first and second irradiation light is not particularly limited as long as it does not significantly deteriorate or decompose the liquid crystal material, the photoresponsive material or the like. However, from the viewpoint of practical preparation and the like, 0.2 mW / cm ^{2 to} 1000 mW / cm ² (more preferably 1 to 100 mW / cm ² ) is preferable.

(vi) In particular, when ultraviolet light is used as the first irradiation light and visible light is used as the second irradiation light, the above-mentioned single-type photoresponsive liquid crystal material or mixture-type photoresponsive liquid crystal material is used. While considering the relationship with the photoresponsive material (specifically, concentration), the intensity of the irradiated ultraviolet light is changed to the intensity of the ultraviolet light in the daily environment (the total light intensity in the ultraviolet light region (wavelength = 280 to 400 nm) is About ² mW / cm ² ) and the intensity of ultraviolet light in the indoor environment (the sum of the intensity in the ultraviolet light region (wavelength = 275 to 380 nm) is 7.3 mW / cm ² ) as much as possible. Visible light intensity in everyday environments (total light intensity in the visible light region is several tens of mW / cm ² ) and in the indoor environment visible light intensity (total light intensity in the visible light region is several mW / cm ² ) It is preferable to make them as close as possible. While the gel material can be prevented from inadvertently transitioning to an isotropic phase by ultraviolet light under a normal use mode used in an everyday environment or indoor environment, This is because stabilization (stabilization of the gel) can be achieved.

(2) Fine particles with chemically modified polymers
(i) Fine particles
(i-1) The fine particles themselves are uniformly dispersed in the photoresponsive liquid crystal material, and accordingly, the polymer in each fine particle also serves to uniformly disperse in the photoresponsive liquid crystal material. This is because, in the entire photoresponsive liquid crystal material, the polymers chemically modified by the fine particles are easily entangled with each other.
(i-2) The material of the fine particles is not particularly limited, but those containing silica as a main component are preferable.
(i-3) The diameter of the fine particles is not particularly limited as long as it is a size that can be dispersed in the photoresponsive liquid crystal material. However, in practice, the diameter of the fine particles is preferably 0.01 to 1 μm (more preferably 0.1 to 0.5 μm) in view of chemical modification, dispersion, ease of handling, and the like of the polymer.

(ii) Polymer
(ii-1) A polymer is chemically modified on the surface of each fine particle. This is because, in a situation where the fine particles themselves are uniformly dispersed in the photoresponsive liquid crystal material, the polymers chemically modified to the fine particles are entangled with each other to form a network-like structure. Thereby, a gel can be formed.
(ii-2) The molecular weight of the polymer is preferably 40,000 or more in terms of polystyrene based on gel permeation chromatography. According to the knowledge obtained by the present inventors, when the molecular weight of the polymer is less than 40,000, the polymers in each fine particle are not easily entangled with each other and a gel is not easily formed. This is because the entanglement becomes effective. Details of this will be described later.

(ii-3) The glass transition temperature Tg of the polymer is preferably set to be higher than the liquid crystal phase-isotropic phase transition temperature _TLC-I in the photoresponsive liquid crystal material. According to the knowledge obtained by the present inventors, under the condition of Tg> _TLC-I , the gel material has an isotropic phase and a polymer phase separation region and a polymer compatibility as shown in FIG. This is because it is known that the region can be expressed, and the characteristics of each region can be specifically used for light modulation without significantly changing the gel hardness. Details of this will also be described later.
(ii-4) A polymer can basically exhibit a desired function as long as the above-described content is satisfied, and the polymer includes an amorphous polymer produced industrially. All polymers can be used.
(ii-5) The chemical modification state of the polymer on the surface of the fine particles is not particularly limited, but is preferably modified at a high density from the viewpoint of entanglement of the polymers in each fine particle.

  (iii) The concentration of fine particles in which the polymer is chemically modified is preferably 5 wt% or more with respect to the photoresponsive liquid crystal material. According to the knowledge obtained by the present inventors, when the fine particle concentration is less than 5 wt%, a gel is hardly formed based on the entanglement of the polymers in each fine particle, whereas when the fine particle concentration is 5 wt% or more, the polymers in each fine particle are This is because the gel is effectively formed based on the entanglement.

2. Characteristics of Gel Material The characteristics of the gel material will be described using a gel material that specifically incorporates the above contents. As the specific gel material, the following polymer / liquid crystal composite gel material 1 and polymer / liquid crystal composite gel material 2 were used.

(1-1) Preparation of polymer / liquid crystal composite gel material 1 Liquid crystal 4-cyano-4′-pentylbiphenyl (5CB, 0.44 g) manufactured by Merck & Co., Ltd. and 4-butyl-4′-methoxyazobenzene (BMAB, 42 mg) ) Was added to prepare a photoresponsive liquid crystal material. To this photoresponsive liquid crystal material, a toluene dispersion (5.95 wt%, 0.82 g) of silica fine particles (PMMA248K-SiP: diameter 650 nm) grafted with polymethyl methacrylate having a molecular weight of 248000 was added and stirred. The mixture was put under reduced pressure for 4 hours or more, and toluene was distilled off (10 kPa, 70 ° C.). Then, it was heated on a hot plate at 120 ° C. and then cooled to room temperature to obtain a polymer / liquid crystal composite gel material 1 (fine particle concentration: 10 wt%).
In this case, silica fine particles (PMMA248K-SiP, diameter 650 nm) whose surface is chemically modified with the above polymethyl methacrylate having a molecular weight of 248000 are prepared prior to the preparation of the polymer / liquid crystal composite gel material 1 (gel material). The compound was synthesized according to the description in paragraphs [0052] to [0054] of Japanese Patent No. 498748. At this time, about the particle diameter, the hydrodynamic diameter was measured by the light-scattering method using the particle diameter measuring apparatus (Zetasizer Nano) made from Malvern. Moreover, since the number average molecular weight of the free polymer produced from EBIB was 248,000, the polymer grafted on the silica surface was expected to have the same length and distribution.

(1-2) Polymer / liquid crystal composite gel material 2
A mixed liquid crystal ZLI-1083 (1.0 g: liquid crystal phase-isotropic phase transition temperature T _LC-I = 53 ° C.) shown in the following (Chemical Formula 1) manufactured by Merck & Co., Ltd. was added to 4-butyl-4′-methoxyazobenzene ( 0.014 g, 1.4 wt%) was added to prepare a photoresponsive liquid crystal material. Next, silica fine particles (PMMA120K-SiP, diameter 470 nm: polymer brush-applied silica fine particles) in which polymethyl methacrylate having a molecular weight of 120,000 (glass transition temperature Tg≈110 ° C.) is chemically modified on the surface are prepared. The toluene dispersion in which it is dispersed (11.54 wt%, 0.89 g) is added to the photoresponsive liquid crystal material and stirred, and the mixture is put under reduced pressure for 10 hours or more to distill off toluene (10 kPa, 60 ° C.). Thereafter, it was heated on a hot plate at 120 ° C. and then cooled to room temperature to obtain a polymer / liquid crystal composite gel material (fine particle concentration: 10 wt%) 2.

  In this case, preparation of silica fine particles (PMMA120K-SiP, diameter 470 nm: silica fine particles provided with a polymer brush) whose surface is chemically modified with polymethyl methacrylate having a molecular weight of 120,000 (glass transition temperature Tg≈110 ° C.), particles About each measurement of a diameter etc., the thing similar to the method used in the above-mentioned polymer / liquid crystal composite gel material 1 was used.

(2) Specific Properties of Gel Material Each property of the gel material will be specifically described below with the polymer / liquid crystal composite gel material 1 and the polymer / liquid crystal composite gel material 2.
(2-1) Kinematic viscoelastic properties of gel materials
(i) The polymer / liquid crystal composite gel material 1 exhibits dynamic viscoelasticity (storage elastic modulus, loss elastic modulus) characteristics associated with temperature changes shown in FIG. The dynamic viscoelasticity (storage elastic modulus, loss elastic modulus) characteristic with the temperature change shown in FIG. Both show the characteristics of the same tendency. The dynamic viscoelasticity was measured using a strain control type dynamic viscoelasticity measuring apparatus, and ARES-RF manufactured by TA Instruments was used as the apparatus. Then, a gel sample was sandwiched between parallel disks having a diameter of 25 mm, and storage elastic modulus (G ′, ●) and loss elastic modulus (G ″, ○) were estimated by measurement at a shear strain of 0.1% and a frequency of 1 Hz. .

(ii) The gel material (polymer / liquid crystal composite gel materials 1 and 2) is, as described above, the liquid crystal phase-isotropic phase transition temperature T _LC-I (hereinafter referred to as phase transition temperature) in the photoresponsive liquid crystal material. The isotropic phase and the liquid crystal phase are developed with reference to _TLC-I (see FIGS. 1, 3, and 4).
(iii) The isotropic phase exists in a temperature region higher than the phase transition temperature TLC _-I (the right region in FIGS. 1, 3, and 4), and in the isotropic phase, as described above, A polymer phase separation region and a polymer compatibility region are to appear.

  (iii-1) The polymer phase separation region is formed in a temperature range lower than that of the polymer compatibility region, as shown in FIGS. In this polymer phase separation region, the temperature of the region adjacent to the polymer compatible region (high temperature region) is close to the temperature of the polymer compatible region, and is isotropic with the polymer in each fine particle. The compatibility with the medium in the phase is high. For this reason, the said gel material exists in a soft gel state in the area | region near a polymer compatibility area | region among polymer phase separation areas.

On the other hand, in this polymer phase separation region, the region in the phase separation state is increased due to a decrease in the compatibility between the medium in the isotropic phase and the polymer. It is supposed to be promoted along with the decline. Therefore, in this polymer phase separation region, as the phase separation state of the polymer increases (decrease in temperature), the entanglement between the polymers in each fine particle proceeds and the network structure is strengthened. As a result, the storage elastic modulus G ′ characteristic is rapidly increased as the temperature is lowered, and the gel material becomes a hard gel having a considerable hardness in a region near the phase transition temperature T _LC-I .
In this case, in the vicinity of the transition temperature _TLC-I in the isotropic phase, most of the polymer is in a phase-separated state, and the storage elastic modulus characteristics of the storage temperature characteristic accompanying the temperature decrease that was abruptly near the transition temperature _TLC-I . The gradient also becomes slow from the vicinity of the transition temperature _TLC-I (see FIGS. 3 and 4).

(iii-2) Specifically, the polymer / liquid crystal composite gel material 1 exhibits the characteristics as shown in FIG. 3 in the isotropic phase. In this case, the storage elastic modulus G ′ is about 10 ² Pa and becomes a soft gel state, and in the temperature region close to the phase transition temperature T _LC-I , the storage elastic modulus G ′ is between 10 ³ Pa and 10 ⁴ Pa. It becomes a hard gel state with the value (see FIG. 3).
Further, the polymer / liquid crystal composite gel material 2 exhibits characteristics as shown in FIG. 4 in the isotropic phase, and the storage elastic modulus G ′ in the high temperature region of the polymer phase separation region. = A soft gel state around 10 ² Pa, and in a temperature region close to the phase transition temperature T _LC-I , a hard gel state is obtained with a storage elastic modulus G ′ = 10 ⁵ Pa (see FIG. 4).

  (iii-3) As shown in FIGS. 1, 3, and 4, the polymer compatibility region is generated in a temperature range higher than the polymer phase separation region. In this polymer compatible region, the gel material is in a sol state.

(vi) The liquid crystal phase is present in a region where the temperature is lower than the phase transition temperature _TLC-I , as shown in FIGS. In this liquid crystal phase, the polymer phase separation region in the aforementioned isotropic phase is continuously continued. In the liquid crystal phase, the gradient of the storage elastic modulus characteristic with the temperature decrease is in the isotropic phase. A slow gradient is maintained in the polymer phase separation region, and the storage elastic modulus characteristic accompanying the temperature decrease extends almost continuously with the gradient. The increase in the storage elastic modulus in the liquid crystal phase is considered to be based on the increase in the elastic modulus of the liquid crystal phase itself.
Specifically, in the case of the polymer / liquid crystal composite gel material 1, as shown in FIG. 3, although the liquid crystal phase is a region somewhat away from the phase transition temperature _TLC-I , the gel hardness is stored. will be increased until the elastic modulus G '= 10 5 ^Pa or more values, in the case of a polymer / liquid crystal composite gel material 2, as shown in FIG. 4, the gel hardness properties, phase transition temperature T _{LC- In the} vicinity of _I , the storage elastic modulus G ′ is increased to a value of 10 ⁵ Pa or more, and the storage elastic modulus (gel hardness) is further increased as the temperature decreases.

(vii-1) Therefore, in the polymer / liquid crystal composite gel materials 1 and 2 constituting the gel material, in the polymer phase separation region in the isotropic phase, the network structure is formed by the entanglement of the polymers in each fine particle. The strength of the body can be improved and the storage elastic modulus can be increased more than before (conventionally about 10 ² Pa: refer to Patent Document 1). For this reason, by making the said gel material into a liquid crystal phase, the storage elastic modulus under the liquid crystal phase can be added, and an elastic deformation characteristic can be remarkably improved accordingly. Thereby, autonomous restoration can be remarkably enhanced by using the gel material under the liquid crystal phase.

  (vii-2) Further, when the gel material is used (processed), among the polymer phase separation regions in the isotropic phase, the region adjacent to the polymer compatible region (the higher temperature side) is bent. If it takes in in a process, the said gel material will be in a comparatively soft gel state in the area | region, and the said gel material can be processed easily. After the processing is completed, the gel material is simply left (naturally cooled), and the gel material moves from the high temperature side to the low temperature side in the polymer phase separation region in the process of changing to the liquid crystal phase. Excellent functionality will be ensured. For this reason, in the manufacturing process of the product using the said gel material, the storage elastic modulus (dynamic viscoelastic characteristic) accompanying the temperature change in the said gel material can be utilized effectively.

(2-2) Dynamic viscoelastic properties associated with changes in the concentration of fine particles with chemically modified polymers
(i) In the gel material (polymer / liquid crystal composite gel material 2), the concentration of fine particles in which the polymer is chemically modified greatly contributes to the dynamic viscoelastic properties.
FIG. 5 shows the concentration of fine particles and dynamic viscoelasticity (storage elastic modulus, loss elastic modulus) by changing the concentration of fine particles in polymer / liquid crystal composite gel material 2 (polymer molecular weight: 120,000) as a specific example of the gel material. Are investigated under the liquid crystal phase (25 ° C.) and the isotropic phase (90 ° C.), respectively. At this time, the dynamic viscoelasticity (storage elastic modulus, loss elastic modulus) was measured using a strain control type dynamic viscoelasticity measuring apparatus, and ARES-RF manufactured by TA Instruments was used as the apparatus. Then, a gel sample is sandwiched between parallel discs having a diameter of 25 mm, and the storage elastic modulus (G ′, ◆, ●) and the loss elastic modulus (G ″, ◇, ○) are measured by measuring at a shear strain of 0.1% and a frequency of 1 Hz. ) Was estimated.

  (ii) According to FIG. 5, in both the liquid crystal phase and the isotropic phase (glass transition temperature Tg or less), the storage elastic modulus began to substantially increase from the fine particle concentration of 5 wt%. This is because, when the fine particle concentration is less than 5 wt%, a gel is hardly formed based on the entanglement between the polymers in each fine particle, whereas from the fine particle concentration of 5 wt% or more, the gel is formed based on the entanglement between the polymers in each fine particle. Considered to get you started.

(iii) Further, according to FIG. 5, in the isotropic phase (90 ° C.), the storage elastic modulus increases as the fine particle concentration increases, whereas in the liquid crystal phase (25 ° C.), the fine particle concentration Although the storage elastic modulus increases with the increase, when the fine particle concentration exceeds 15 wt%, the storage elastic modulus reaches a saturation value, and when the fine particle concentration reaches 20 wt%, the storage elastic modulus is about the same as the fine particle concentration of 15 wt%. It became. However, this is considered to exceed the measurement limit of the device from the comparison with the storage elastic modulus in the isotropic phase. In the liquid crystal phase, the storage elasticity of the order of 10 ⁶ Pa or more when the fine particle concentration is 20 wt%. The rate is expected to be expected. For this reason, the upper limit of the concentration of the fine particles is not particularly limited as long as the fine particles can be dispersed in the photoresponsive liquid crystal material.
(iv) Therefore, the polymer is chemically modified from the viewpoint of uniformly dispersing the fine particles in the photoresponsive liquid crystal material to smoothly entangle the polymers and ensuring that the gel material is a gel. The concentration of the fine particles is preferably 5 wt% or more with respect to the photoresponsive liquid crystal material.

(2-3) Dynamic viscoelastic properties associated with changes in molecular weight of polymers
(i) In the gel material (polymer / liquid crystal composite gel material 2), the molecular weight of the polymer greatly contributes to the dynamic viscoelastic properties.
FIG. 6 shows a polymer / liquid crystal composite gel material (fine particle concentration: 10 wt%) 2 that is a specific example of the gel material by changing the molecular weight of the polymer (value under polystyrene conversion based on gel permeation chromatography). The relationship between the molecular weight and the dynamic viscoelasticity (storage elastic modulus, loss elastic modulus) was investigated under a liquid crystal phase and an isotropic phase (below the glass transition temperature Tg of the polymer). At this time, dynamic viscoelasticity (storage elastic modulus, loss elastic modulus) was measured using a rotary dynamic viscoelasticity measuring apparatus. TA-instruments ARES-RF is used as a device, a gel sample is sandwiched between parallel disks with a diameter of 25 mm, and a storage elastic modulus (G ′, ◆, ●) and a shear strain of 0.1% are measured at a frequency of 1 Hz. Loss elastic modulus (G '', ◇, ○) was estimated.
(ii) According to FIG. 6, in both the liquid crystal phase and the isotropic phase, the storage elastic modulus (gel rigidity) is not saturated until the molecular weight of the polymer reaches 40000, and before reaching that value. The storage elastic modulus greatly increased as the molecular weight of the polymer increased. This is because, when the molecular weight of the polymer is less than 40,000, the polymers in each fine particle are not easily entangled with each other and a gel is not easily formed. On the other hand, when the molecular weight of the polymer is 40000 or more, This is considered to be because the gel is stably formed.
(iii) Therefore, from the viewpoint of stabilizing the gel, the molecular weight of the polymer is preferably 40,000 or more in terms of polystyrene based on gel permeation chromatography.

(2-4) Optical properties of gel material The gel material has a property of changing light transmittance based on a phase transition between a liquid crystal phase and an isotropic phase.
FIG. 7 is a graph showing optical characteristics associated with a temperature change using the polymer / liquid crystal composite gel material 2. According to FIG. 7, it became a cloudy and opaque state at 25 ° C., and became transparent at 55 ° C. and 85 ° C. above the nematic phase-isotropic phase transition temperature of 53 ° C. This is because the mixed liquid crystal ZLI-1083 constituting the polymer / liquid crystal composite gel material 2 is in a liquid crystal phase at 25 ° C. and thus scatters light and exceeds the nematic phase-isotropic phase transition temperature (53 ° C.). This is probably because the mixed liquid crystal ZLI-1083 did not scatter light at temperatures of 55 ° C. and 85 ° C. due to the transition to the isotropic phase.

(2-5) Phase transition temperature _TLC-I characteristics and phase separation _- phase solution transition temperature (hereinafter referred to as transition temperature _TIG-IS ) characteristics associated with concentration change (photoresponsive material concentration change) of the first form
(i) The gel material not only significantly enhances autonomous restoration, but also has a property of changing only optical properties while maintaining a hard gel state.
FIG. 8 shows the relationship between the concentration (mol%) of the photoresponsive material and the phase transition temperature TLC _-I in the polymer / liquid crystal composite gel material 1 (polymer molecular weight 248000). In this polymer / liquid crystal composite gel material 1, when the photoresponsive material is in the second form (the photoresponsive material is in the second form (trans form) by non-irradiation or irradiation with the second irradiation light). The initial phase transition temperature T _LC-I (photo _- responsive material) regardless of the concentration state of the photo-responsive material forming the second form thereof Is substantially the same value (phase transition temperature T _LC-I ) as the phase transition temperature T _{LC-I in a} state in which no is contained (indicated by the characteristic line f0-1). On the other hand, when the photoresponsive material is photoisomerized to the first form (cis body) by the first irradiation light (the photoresponsive material becomes the first form (cis body) by the irradiation of the first irradiation light). 100% photoisomerized state (see the characteristic line in the plot ●), and from the initial phase transition temperature T _LC-I (35 ° C.) as the concentration of the photoresponsive material forming the first form increases. It shows a tendency to gradually decrease (indicated by characteristic line f1-1).

(ii) FIG. 8 also shows the relationship between the concentration (mol%) of the photoresponsive material in the polymer / liquid crystal composite gel material 1 and the transition temperature _TIG-IS . The transition temperature T _IG-IS indicates the boundary temperature between the aforementioned polymer phase separation region and the polymer compatibility region in the isotropic phase. In this polymer / liquid crystal composite gel material 1, the optical response When the light-sensitive material is in the second form (the state in which the photoresponsive material is 100% photoisomerized to the second form (trans form) by non-light irradiation or irradiation of the second irradiation light: characteristics of plot □ The transition temperature T _IG-IS is maintained at substantially the same temperature as the initial temperature of the transition temperature T _IG-IS until the concentration of the photoresponsive material forming the second form reaches a predetermined concentration. When the concentration exceeds the predetermined concentration, the transition temperature TIG _-IS gradually starts to increase (indicated by the characteristic line f0-2). On the other hand, when the photoresponsive material is photoisomerized to the first form (cis body) by the first irradiation light (the photoresponsive material becomes the first form (cis body) by the irradiation of the first irradiation light). 100% photoisomerized state (refer to the characteristic line of the plot ■), the transition temperature _TIG-IS gradually increases from its initial temperature as the concentration of the photoresponsive material forming the first form increases. It shows a tendency to decrease (indicated by characteristic line f1-2).

  (iii-1) Therefore, the region below the characteristic line f0-1 is the region of the liquid crystal phase of the photoresponsive liquid crystal material when no light is irradiated (when the first irradiation light is not irradiated), and the characteristic line f1 −1 is an isotropic phase region of the photoresponsive liquid crystal material that changes state with the irradiation of the first irradiation light, and therefore, below the characteristic line f0-1 as shown in FIG. A region A1 to which both the region above the characteristic line f1-1 belongs (see hatched portion) A1 is a region of the liquid crystal phase of the photoresponsive liquid crystal material at the time of non-light irradiation, and from the light non-irradiation state This is an isotropic phase region of the photoresponsive liquid crystal material whose state changes with light irradiation. For this reason, in the case where the polymer / liquid crystal composite gel material 1 belongs to the region A1 (in FIG. 9, an example of an existing position is indicated by a point M1), the polymer / liquid crystal composite gel material 1 is not irradiated with light. When the photoresponsive liquid crystal material is in a liquid crystal phase and becomes opaque, and the polymer / liquid crystal composite gel material 1 is irradiated with the first irradiation light, the polymer / liquid crystal composite gel material 1 The photoresponsive liquid crystal material becomes isotropic and becomes transparent.

  (iii-2) The region below the characteristic line f0-2 is a region extending from the polymer phase separation region to the liquid crystal phase in the isotropic phase of the photoresponsive liquid crystal material when no light is irradiated. The lower region of f1-2 is a region extending from the polymer phase separation region to the liquid crystal phase in the isotropic phase of the photoresponsive liquid crystal material that changes state with the irradiation of the first irradiation light. As shown in FIG. 10, the region (see the hatched portion) A2 that belongs to the region below the characteristic line f0-2 and to which both the region below the characteristic line f1-2 belongs is a region of the photoresponsive liquid crystal material when no light is irradiated. Polymer phase separation in the isotropic phase of a photoresponsive liquid crystal material that is in the region from the polymer phase separation region to the liquid crystal phase in the isotropic phase and changes state from the non-irradiated state to the light irradiation The region extends from the region to the liquid crystal phase. For this reason, in the case where the polymer / liquid crystal composite gel material 1 belongs to the region A2 (in FIG. 10, an example of an existing position is indicated by a point M2), the polymer / liquid crystal composite gel material 1 is At that time (when no light is irradiated), it belongs to the region from the polymer phase separation region to the liquid crystal phase in the isotropic phase and becomes a hard gel state. When the first irradiation light is irradiated to the polymer / liquid crystal composite gel material 1, the polymer phase separation region in the isotropic phase at that time (at the time of irradiation with the first irradiation light) is used. It belongs to the region over the liquid crystal phase and becomes a hard gel state.

(iii-3) From the above contents of the area A1 (see FIG. 9) and the area A2 (see FIG. 10), the overlapping area A3 of the area A1 and the area A2 is as shown in FIG. It is the region of the liquid crystal phase of the photoresponsive liquid crystal material and is the region of the isotropic phase of the photoresponsive liquid crystal material that changes its state from light non-irradiation state with light irradiation. In the isotropic phase of the photoresponsive liquid crystal material, which is a region from the polymer phase separation region to the liquid crystal phase in the isotropic phase of the liquid crystalline liquid crystal material and changes its state with the light irradiation from the non-light-irradiated state The region extends from the polymer phase separation region to the liquid crystal phase. For this reason, in the case where the polymer / liquid crystal composite gel material 1 belongs to the region A3 (in FIG. 11, an example of an existing position is indicated by the point M3), the polymer / In the liquid crystal composite gel material 1, the photoresponsive liquid crystal material is maintained in a liquid crystal phase, and becomes an opaque state under a hard gel state. When the first irradiation light is irradiated to the polymer / liquid crystal composite gel material 1, the polymer phase separation region in the isotropic phase at that time (at the time of irradiation with the first irradiation light) The polymer / liquid crystal composite gel material 1 belongs, and the polymer / liquid crystal composite gel material 1 becomes transparent under a hard gel state. After that, when the polymer / liquid crystal composite gel material 1 is irradiated with the second irradiation light, the photoresponsive liquid crystal material is phase-shifted to the liquid crystal phase when no light is irradiated, and the polymer / liquid crystal composite is obtained. The gel material 1 returns to the opaque state under the original hard gel state.
(iii-4) Therefore, in the polymer / liquid crystal composite gel material 1, the light transmittance can be adjusted while maintaining the hard gel state.

(iv) In the above case, the region where the polymer / liquid crystal composite gel material 1 is present is, as shown in FIG. 11, the photoresponsiveness that changes its state with the irradiation of the first irradiation light. A region A3-1 (region approximate to the characteristic line f1-1) close to the liquid crystal phase of the liquid crystal material is preferable.
Under the isotropic phase, the change in storage elastic modulus due to temperature change has the property that the storage elastic modulus increases as the temperature decreases, and in the isotropic phase, a region close to the phase transition temperature _TLC-I. Shows the largest storage elastic modulus (see FIGS. 3 and 4), and even if the phase transition from the non-irradiation state to the isotropic phase by the first irradiation light irradiation, the storage elastic modulus is liquid crystal It is because it can suppress as much as possible that it falls from the big storage elastic modulus in a phase. As a result, even when light modulation is performed by phase transition between the liquid crystal phase and the isotropic phase by light irradiation, the storage elastic modulus in the isotropic phase is not reduced as much as possible with respect to the storage elastic modulus in the liquid crystal phase. Thus, only the optical properties can be changed without significantly changing the gel hardness.

(v) The polymer / liquid crystal composite gel material 1 has the above-mentioned region A3 (preferably A3−) by adjusting the use temperature and the photoresponsive material concentration (concentration that can be converted into the first form (cis body)). Belongs to 1).
Specifically, characteristic lines f1-1, f1-2 is responsive material concentration accompanying phase transition temperature increases _{T LC-I,} there is a tendency that the transition temperature _{T IG-IS} decreases, the characteristic line Considering the tendency of f1-1 and f1-2, and the temperature not higher than the phase transition temperature T _LC-I (characteristic line f0-1) at the time of no light irradiation, the polymer / liquid crystal composite gel material 1 Operating temperature and photoresponsive material concentration are determined.
For example, when the use temperature of the polymer / liquid crystal composite gel material 1 is 25 ° C., the concentration of the photoresponsive material (specifically, the cis-body concentration) is 4 mol%, the position is below the characteristic line f1-1. Although it cannot belong to the region A3 (preferably A3-1) (see the point P1 in FIG. 11), if the concentration of the photoresponsive material is 5 mol% or more even at the same temperature, the above region The polymer / liquid crystal composite gel material 1 can belong to A3 (A3-1) (see point P2 in FIG. 11).
Further, when it is desired to lower the use temperature of the polymer / liquid crystal composite gel material 1 from about 25 ° C. to about 22 ° C., the concentration of the photoresponsive material is insufficient if it is 5 mol% as described above, and must be 6 mol% or more. (Refer to point P3 in FIG. 11).

(vi) The polymer / liquid crystal composite gel material 1 has not only the above-described characteristics, but also a characteristic capable of regenerating a damaged (ruptured) portion by heating.
The polymer / liquid crystal composite gel material 1 belongs to the polymer phase separation region in the isotropic phase by the first irradiation light irradiation, and the adjacent region of the polymer phase separation region has a sol state. (Refer to the upper and lower regions with reference to the characteristic line f1-2 in FIG. 11). For this reason, when damage such as breakage occurs in the polymer / liquid crystal composite gel material 1, the polymer / liquid crystal composite gel material 1 is separated into a polymer phase in the isotropic phase by the first irradiation light irradiation. The damaged portion becomes a sol if it belongs to the region and the polymer / liquid crystal composite gel material 1 is further transferred to the polymer compatible region by slightly heating the damaged portion. Will be. If the repaired part is left after the repair, the repaired part will fall in the polymer phase separation region in the isotropic phase due to a decrease in temperature and return to the hard gel. For this reason, in the polymer / liquid crystal composite gel material 1, not only can the light transmittance be adjusted in a hard gel state, but also when the surface of the member is damaged (breakage, etc.), the polymer / liquid crystal composite The damaged part of the gel material 1 can be regenerated.

In FIG. 11, the polymer / liquid crystal composite gel material 1 at the point P2 belonging to the region A3 will be described as an example. If the polymer / liquid crystal composite gel material 1 is irradiated with the first irradiation light, the high The molecule / liquid crystal composite gel material 1 belongs to the polymer phase separation region in the isotropic phase. After that, if the polymer / liquid crystal composite gel material 1 is heated at about 4 to 5 ° C., the isotropic phase is obtained. It belongs to the polymer compatible region in (see point P4). Thereby, the damaged portion becomes sol and is repaired as described above.
In the above specific example, for ease of understanding, the polymer / liquid crystal composite gel material 1 is first made to belong to the polymer phase separation region in the isotropic phase by light irradiation, and then the polymer / liquid crystal composite. Although the gel material 1 belongs to the polymer compatible region in the isotropic phase by heating, of course, on the contrary, the polymer / liquid crystal composite gel material 1 is first heated and then irradiated with light. May belong to the polymer compatible region in the isotropic phase.

(2-5) Mechanically Responsive Sol-Gel Transition Characteristics of Gel Material The polymer / liquid crystal composite gel material 2 has a high-speed mechanical response sol-gel transition characteristic shown in FIG. At this time, dynamic viscoelasticity (storage elastic modulus, loss elastic modulus) was measured using a strain control type dynamic viscoelasticity measuring apparatus, and ARES-RF manufactured by TA Instruments was used for the apparatus. And the gel sample was pinched | interposed into the parallel disk of diameter 25mm, and it measured in shear distortion 0.1% and frequency 1Hz.
According to FIG. 12, when the mechanical strain (Strain, ■) applied to the polymer / liquid crystal composite gel material 1 is 0.1%, the storage elastic modulus (G ′, ◆) is the loss elastic modulus (G ′. The polymer / liquid crystal composite gel material 2 became an elastic body (gel), but the mechanical strain (Strain, ■) applied to the polymer / liquid crystal composite gel material 1 was 100%. In this case, the loss elastic modulus (G ″, ○) becomes larger than the storage elastic modulus (G ′, ◆), and the polymer / liquid crystal composite gel material 1 becomes a viscous body (sol) and is close to a liquid. It became a state.

3. The gel material can be used as a coating material to be coated on the substrate surface or the substrate itself.
If the gel material is used as a covering material to be coated on the surface of the base material or the base material itself, the base material can have the above-described autonomous restoration function.
In addition, when the gel material is coated on a transparent base material as a coating material or used as the base material itself, by irradiating the first and second irradiation light (ultraviolet light, visible light), Not only can the light transmittance of these base materials be changed, but also in the adjustment of the light transmittance, the high gel rigidity (storage elastic modulus) of the coating material or the base material (formed by the gel material) changes. This can be suppressed.
Furthermore, when the base material is coated with the gel material as a coating material, the mechanically responsive sol-gel transition characteristics of the gel material can be used (see FIG. 12). By applying an external force, the coating workability can be improved in a sol state. Of course, in this case, if the external force is removed from the coating material in the sol state, the coating material returns to the gel state with quick response.
Furthermore, when the base material itself is formed using the gel material, a soft gel state generated in a region (high temperature side) adjacent to the polymer compatible region in the polymer phase separation region in the isotropic phase. Can be used effectively in manufacturing processes such as bending.

4). Examples are provided to further support the above contents.
(1) Autonomous restoration experiment 0.4 g of the aforementioned polymer / liquid crystal composite gel material 1 (fine particle concentration: 10 wt%) is put in a mold, heated on a hot plate at 120 ° C., cooled to room temperature, did. The polymer / liquid crystal composite gel material 2 in a gel state was taken out from the mold into a petri dish, and the polymer / liquid crystal composite gel material 1 was compressed with a force of 30 N. In this compression test, a 60 ° angle measuring adapter was attached to a digital force gauge FGP-50 manufactured by Nidec Simpo, and the gel surface was compressed with a predetermined force.
This result is shown in the photograph shown in FIG. As apparent from FIG. 13, the deformation was observed immediately after the compression, but the deformation gradually recovered, and after 1 hour, the deformation completely returned to the original state.

(2) Optical test and dynamic viscoelasticity test associated with changes in light response in gel materials
When the polymer / liquid crystal composite gel material 1 was irradiated with ultraviolet light (wavelength 365 nm, light intensity 10 mW / cm ² ) for 10 minutes, as shown in FIG. 14, the polymer / liquid crystal composite that was opaque before ultraviolet light irradiation was used. Gel material 1 changed to transparent. This result shows that the phase structure of the photoresponsive liquid crystal material is liquid crystal due to the photoisomerization reaction of the photoresponsive compound (4-butyl-4′-methoxyazobenzene) contained in the photoresponsive liquid crystal material based on ultraviolet light irradiation. This is probably because the phase has changed to an isotropic phase (a temperature region close to the changed phase transition temperature _TLC-I among the isotropic phases).
On the other hand, when the dynamic viscoelastic characteristics accompanying the photoresponse change in the polymer / liquid crystal composite gel material 1 described above were examined, the polymer / liquid crystal before irradiation with ultraviolet light (wavelength 365 nm, light intensity 10 mW / cm ² ). The storage elastic modulus of the composite gel material 1 was 3.7 × 10 ⁴ Pa, but when the polymer / liquid crystal composite gel material 1 was irradiated with ultraviolet light, the storage elasticity of the polymer / liquid crystal composite gel material 1 was The rate was 3.0 × 10 ⁴ Pa, which only changed the degree of experimental error.
From these results, it was confirmed that only the optical properties of the polymer / liquid crystal composite gel material 1 were changed by ultraviolet light irradiation while maintaining the storage elastic modulus substantially.

  By forming the surface of various final products (home appliances, cars, etc.) as a covering material or base material that exhibits light irradiation and an autonomous restoration function, the product life can be extended. In addition, since the optical properties can be modulated while maintaining the gel rigidity, medical members such as a diseased part protective material (gibbs) that can be confirmed with the attached part, and display of recording materials, screens, etc. It can also be used as a member. Furthermore, since the gel is highly elastic, it can be used as a shock absorber.

Phase transition temperature of liquid crystal phase-isotropic phase in TLC _-I photoresponsive liquid crystal material A1 region A2 region A3 region A3-1 Preferred region (of region A3, the state changes with irradiation of the first irradiation light Area close to the liquid crystal phase of photoresponsive liquid crystal material)

Claims (8)

A light transmittance adjusting material having an autonomous resilience improving function, comprising a photoresponsive liquid crystal material that is photoisomerized by light irradiation and a polymer-modified fine particle having a surface grafted with a polymer having a molecular weight of 40000 or more. ,
The photoresponsive liquid crystal material is photoisomerized by irradiating the light transmittance adjusting material with light, and the liquid crystal phase-isotropic phase transition temperature of the light transmittance adjusting material is the use temperature of the light transmittance adjusting material. A phase transition from a liquid crystal phase to an isotropic phase by changing from above to below the use temperature, or a liquid crystal phase-isotropic phase transition temperature of the light transmittance adjusting material is the light transmittance. Those that cause a phase transition from the isotropic phase to the liquid crystal phase by changing from below the use temperature to above the use temperature is used,
As the polymer, in any of the post before the light irradiation and the light irradiation also, phase separation relative to the photo-responsive liquid crystal material of the polymer modified fine particles - compatible transition temperature, the crystal phase - from isotropic phase transition temperature The higher one is used,
The phase separation-phase transition temperature is adjusted to be higher than the use temperature of the light transmittance adjusting material both before and after light irradiation, and at the use temperature, the photoresponse The polymer-modified fine particles are in a phase-separated state with respect to the conductive liquid crystal material ,
A light transmittance adjusting material having a function of improving the self-restoration characteristic. The polymer-modified fine particles are contained in an amount of 5 wt% or more with respect to the photoresponsive liquid crystal material .
The light transmittance adjusting material having an autonomous restoring property improving function according to claim 1 . The photoresponsive liquid crystal material is a liquid crystal material and a photoresponsive material that undergoes photoisomerization by light irradiation to cause the liquid crystal material to transition from a liquid crystal phase to an isotropic phase or from an isotropic phase to a liquid crystal phase. A mixture,
The light transmittance adjusting material having an autonomous restoring property improving function according to claim 1 . In the case of using the light transmittance adjusting material at a certain temperature,
The concentration of the photoresponsive material so that the use temperature of the light transmittance adjusting material is closer to the liquid crystal phase-isotropic phase transition temperature than the phase separation-phase transition temperature before light irradiation. Has been adjusted,
The light transmittance adjusting material having an autonomous restoring property improving function according to claim 3 . Used as a coating material to be coated on the surface of the substrate or the substrate itself,
The light transmittance adjusting material which has the autonomous restoring property improvement function of any one of Claims 1-4 characterized by the above-mentioned . Light transmittance having a function of improving the self-recoverability by mixing a photoresponsive liquid crystal material that is photoisomerized by light irradiation and polymer-modified fine particles grafted with a polymer having a molecular weight of 40000 or more on the surface. A method for manufacturing the adjusting material,
The photoresponsive liquid crystal material is photoisomerized by irradiating the light transmittance adjusting material with light, and the liquid crystal phase-isotropic phase transition temperature of the light transmittance adjusting material is the use temperature of the light transmittance adjusting material. A phase transition from a liquid crystal phase to an isotropic phase by changing from above to below the use temperature, or a liquid crystal phase-isotropic phase transition temperature of the light transmittance adjusting material is the light transmittance. Using what causes a phase transition from the isotropic phase to the liquid crystal phase by changing from below the use temperature of the adjustment material to above the use temperature,
As the polymer, in any of the post before the light irradiation and the light irradiation also, phase separation relative to the photo-responsive liquid crystal material of the polymer modified fine particles - compatible transition temperature, the crystal phase - from isotropic phase transition temperature Use a higher one,
As the mixture, the phase separation-phase transition temperature is higher than the use temperature of the light transmittance adjusting material both before and after light irradiation ,
A method for producing a light transmittance adjusting material having a function of improving the self-restoring property characterized by the above. A member is configured using the light transmittance adjusting material according to claim 1 ,
When increasing the light transmittance of the member, the member is irradiated with light to cause the photoresponsive liquid crystal material in the member to phase change to an isotropic phase,
When reducing the light transmittance of the member , the member is irradiated with light to cause the photoresponsive liquid crystal material in the member to undergo a phase transition to a liquid crystal phase.
A method of using a light transmittance adjusting material having an autonomous restoration improving function characterized by this . When the surface of the member that is configured using an optical transmittance adjusting material of claim 1 is damaged by performing light irradiation and heating Metropolitan to damage portions of the member, the photo-responsive liquid crystal The material is transferred to an isotropic phase, and the polymer-modified fine particles are in a compatible state with the photoresponsive liquid crystal material to repair a damaged portion of the member.
A method for repairing a light transmittance adjusting material having a function of improving the self-restoring property characterized by this.