JP2006063097A - Silica/metal complex composite material and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite material which contains a metal complex inside silica and can be controlled into various shapes, and a simple manufacturing method of the composite material. <P>SOLUTION: The composite material comprises a metal complex, which is comprised of a polymer (a) having a linear polyethyleneimine skeleton and at least one metal ion (b) coordinating thereto, and silica (c) covering the same. The manufacturing method of the composite material comprises the following steps: (1) a step for causing the polymers having the linear polyethyleneimine skeleton to associate in an aqueous medium; (2) a step for obtaining a composite of the associated polymer and silica by adding an alkoxysilane to the associated polymer in the presence of the aqueous medium; and (3) a step for causing the metal ion to coordinate to the linear polyethyleneimine skeleton in the polymer by impregnating the composite of the associated polymer and silica with a solution having dissolved the metal ion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composite material in which a metal complex composed of a polymer and a metal ion is supported on silica, and a method for producing the composite material.

  A composite material of a metal complex and silica by fixing the metal complex to silica is widely used for a chemical reaction catalyst, an electrochemical sensor, a solid polymer electrolyte, and the like. In particular, when a composite in which a metal complex is introduced into mesoporous silica is used for application, a high surface area of the silica surface, a uniform distribution of complex active sites in the nanocavity, fast diffusion of the substrate compound, heat resistance of the catalyst support, Since many advantages such as acid resistance are predicted, metal complex immobilization technology using mesoporous silica as a support has attracted much attention (see Non-Patent Documents 1 to 6).

  However, the composites of these conventional metal complexes and silica are limited to silica powder or particle state, and they cannot form a silica nanofiber structure. In addition, in the production method, the process is complicated, such as obtaining a complex by introducing an amino group, an imino group, or the like into the silica skeleton by a chemical bond and coordinating a metal ion thereto.

C. T.A. Kresge et al. , Nature, (1992), 359, p. 710 A. Monnier et al. Science, (1993), 261, p1299. S. A. Davis et al. , Nature, (1997), 385, p420. T.A. Kang et al. , J .; Mater. Chem. (2004) 14, p1043 B. Lee et al. , Langmuir, (2003) 19, p4246. K. Zakir et al. , Adv. Mater. (2002) 14, p1053)

  The problem to be solved by the present invention is to provide a composite material containing a metal complex in silica, which can be controlled in various shapes, and a simple method for producing the composite material.

  In the present invention, various shapes of silica are induced by the nanofibers of the aggregate of the polymer (a) having a linear polyethyleneimine skeleton, and the nanofibers of the polymer aggregate in the silica concentrate metal ions. Thus, various shapes of composite materials containing a metal complex in silica can be realized.

  That is, the present invention provides a composite material in which silica (c) is coated with a metal complex in which at least one metal ion (b) is coordinated to a polymer (a) having a linear polyethyleneimine skeleton.

Furthermore, the present invention provides
(1) a step of associating a polymer having a linear polyethyleneimine skeleton in an aqueous medium;
(2) a step of obtaining a composite of the polymer aggregate and silica by adding alkoxysilane to the polymer aggregate in the presence of an aqueous medium;
(3) contacting the composite of the polymer and silica with a solution in which metal ions are dissolved to coordinate the metal ions to the linear polyethyleneimine skeleton in the polymer;
The present invention provides a method for producing a silica / metal complex composite material in which the above is essential.

  In the composite material of the present invention, the shape formed by the aggregate of the polymer having a linear polyethyleneimine skeleton induces the shape of silica, and metal ions enter the inside of the silica so that the polymer is distributed to the metal ions. A coordination metal complex is formed. Therefore, the obtained composite material can be a variety of shapes such as a one-dimensional fiber shape, a two-dimensional film shape, or a complicated three-dimensional shape having a hierarchical structure such as a star shape, a petal shape, a brush shape, Various shapes such as a spherical shape, a columnar shape, and a plate shape can be controlled.

  Furthermore, the metal complex in the composite material of the present invention is characterized in that it contains ions such as alkali metal, alkaline earth metal, and transition metal. Therefore, the composite material of the present invention can be expected to be applied to a solid electrolyte, a solid catalyst, a nano additive, and a nano thin film material. Moreover, it can be expected that the metal complex is converted into metal nanoparticles by treating with a heat treatment or a reducing agent.

  The composite material of the present invention is obtained by coating silica (c) with a metal complex in which at least one metal ion (b) is coordinated to a polymer (a) having a linear polyethyleneimine skeleton.

[Polymer having linear polyethyleneimine skeleton (a)]
The linear polyethyleneimine skeleton as used in the present invention refers to a polymer skeleton having an ethyleneimine unit of a secondary amine as a main structural unit. In the skeleton, a structural unit other than the ethyleneimine unit may be present, but if the constant chain length of the polymer chain is a continuous ethyleneimine unit, the polymer having the linear polyethyleneimine skeleton is present. It is preferable because an aggregate composed of crystals (hereinafter, the aggregate is abbreviated as a polymer aggregate (d)) can be easily formed. The length of the linear polyethyleneimine skeleton is preferably within a range in which the polymer having the skeleton can form an aggregate, and in order to form the polymer aggregate (d), the ethylene of the skeleton is preferably formed. The number of repeating units of imine units is preferably 10 or more, particularly preferably in the range of 20 to 10,000.

  The polymer (a) having a linear polyethyleneimine skeleton (hereinafter simply referred to as polymer (a)) used in the present invention has the above-mentioned linear polyethyleneimine skeleton in its structure. Any shape may be used, and the shape may be linear, star or comb. The polymer (a) can give the polymer aggregate (d) in an aqueous medium (herein, the aqueous medium refers to water or a mixed solvent of water and a water-soluble organic solvent).

  Further, these linear, star-shaped or comb-shaped polymers may be composed of only a linear polyethyleneimine skeleton or a block composed of a linear polyethyleneimine skeleton (hereinafter abbreviated as a polyethyleneimine block). And a block copolymer of the other polymer block. Other polymer blocks include, for example, water-soluble polymer blocks such as polyethylene glycol, polypropionylethyleneimine, polyacrylamide, or polystyrene, polyoxazoline polyphenyloxazoline, polyoctyloxazoline, polydodecyloxazoline, polyacrylates Hydrophobic polymer blocks such as polymethyl methacrylate and polybutyl methacrylate can be used. By using a block copolymer with these other polymer blocks, the shape and characteristics of the polymer aggregate (d) can be adjusted.

  When the polymer (a) is a block copolymer, the ratio of the linear polyethyleneimine skeleton in the polymer (a) is preferably within a range in which the polymer aggregate (d) can be formed. In order to form d), the proportion of the linear polyethyleneimine skeleton in the polymer (a) is preferably 40 mol% or more, and more preferably 50 mol% or more.

  The polymer (a) is obtained by hydrolyzing a polymer having a linear skeleton composed of polyoxazolines serving as a precursor thereof (hereinafter abbreviated as a precursor polymer) under acidic conditions or alkaline conditions. Can be easily obtained. Therefore, the shape of a polymer having a linear polyethyleneimine skeleton such as a linear shape, a star shape, or a comb shape can be easily designed by controlling the shape of the precursor polymer. Further, the degree of polymerization and the terminal structure can be easily adjusted by controlling the degree of polymerization and the terminal functional group of the precursor polymer. Furthermore, when forming a block copolymer having a linear polyethyleneimine skeleton, the precursor polymer is used as a block copolymer, and the linear skeleton composed of polyoxazolines in the precursor is selectively hydrolyzed. Can be obtained at

  The precursor polymer can be synthesized by a cationic polymerization method or a synthesis method such as a macromonomer method using an oxazoline monomer. By selecting an appropriate synthesis method and initiator, a linear polymer can be obtained. It is possible to synthesize precursor polymers having various shapes such as a star shape or a comb shape.

  Oxazoline monomers such as methyl oxazoline, ethyl oxazoline, methyl vinyl oxazoline, and phenyl oxazoline can be used as the monomer that forms a linear skeleton composed of polyoxazolines.

  As the polymerization initiator, a compound having a functional group such as an alkyl chloride group, an alkyl bromide group, an alkyl iodide group, a toluenesulfonyloxy group, or a trifluoromethylsulfonyloxy group in the molecule can be used. These polymerization initiators can be obtained by converting the hydroxyl groups of many alcohol compounds into other functional groups. Of these, brominated, iodinated, toluene sulfonated and trifluoromethyl sulfonated functional groups are preferred because of high polymerization initiation efficiency, and alkyl bromide and toluene sulfonate alkyl are particularly preferred.

  Moreover, what converted the terminal hydroxyl group of poly (ethylene glycol) into bromine or iodine, or converted into a toluenesulfonyl group can also be used as a polymerization initiator. In that case, the degree of polymerization of poly (ethylene glycol) is preferably in the range of 5 to 100, particularly preferably in the range of 10 to 50.

  Also, dyes having a functional group having the ability to initiate cationic ring-opening living polymerization and having a skeleton of any of a porphyrin skeleton, a phthalocyanine skeleton, or a pyrene skeleton having a light emission function, an energy transfer function, and an electron transfer function by light Can impart a special function to the resulting polymer.

  The linear precursor polymer is obtained by polymerizing the oxazoline monomer with a polymerization initiator having a monovalent or divalent functional group. Examples of such a polymerization initiator include methyl benzene, methyl benzene bromide, methyl benzene iodide, methyl benzene toluene sulfonate, methyl benzene trifluoromethyl sulfonate, methane bromide, methane iodide, toluene sulfonic acid. Monovalent ones such as methane or toluenesulfonic anhydride, trifluoromethylsulfonic anhydride, 5- (4-bromomethylphenyl) -10,15,20-tri (phenyl) porphyrin, or bromomethylpyrene, dibromo Divalent ones such as methylbenzene, diiodomethylbenzene, dibromomethylbiphenylene, or dibromomethylazobenzene can be mentioned. In addition, linear polyoxazolines that are industrially used such as poly (methyloxazoline), poly (ethyloxazoline), or poly (methylvinyloxazoline) can be used as a precursor polymer as they are.

  The star-shaped precursor polymer is obtained by polymerizing the oxazoline monomer as described above with a polymerization initiator having a trivalent or higher functional group. Examples of the trivalent or higher polymerization initiator include trivalent compounds such as tribromomethylbenzene, tetravalent compounds such as tetrabromomethylbenzene, tetra (4-chloromethylphenyl) porphyrin, and tetrabromoethoxyphthalocyanine. A pentavalent or higher valent compound such as hexabromomethylbenzene and tetra (3,5-ditosilylethyloxyphenyl) porphyrin can be used.

  In order to obtain a comb-like precursor polymer, an oxazoline monomer can be polymerized from the polymerization initiating group using a linear polymer having a polyvalent polymerization initiating group. It can also be obtained by halogenating a hydroxyl group of a polymer having a hydroxyl group in a side chain such as polyvinyl alcohol with bromine or iodine, or converting it to a toluenesulfonyl group and then using the converted moiety as a polymerization initiating group. .

  As a method for obtaining a comb-like precursor polymer, a polyamine type polymerization terminator can also be used. For example, a monovalent polymerization initiator is used to polymerize oxazoline, and the end of the polyoxazoline is bonded to the amino group of a polyamine such as polyethyleneimine, polyvinylamine, or polypropylamine to obtain a comb-shaped polyoxazoline. Can do.

  Hydrolysis of the linear skeleton composed of the polyoxazolines of the precursor polymer obtained as described above may be carried out under either acidic conditions or alkaline conditions.

  Hydrolysis under acidic conditions can obtain polyethyleneimine hydrochloride, for example, by stirring polyoxazoline under heating in an aqueous hydrochloric acid solution. By treating the obtained hydrochloride with excess ammonium water, a basic polyethyleneimine crystal powder can be obtained. The hydrochloric acid aqueous solution used may be concentrated hydrochloric acid or an aqueous solution of about 1 mol / L, but it is desirable to use a 5 mol / L aqueous hydrochloric acid solution for efficient hydrolysis. The reaction temperature is preferably around 80 ° C.

  For hydrolysis under alkaline conditions, polyoxazoline can be converted into polyethyleneimine by using, for example, an aqueous sodium hydroxide solution. After reacting under alkaline conditions, the reaction solution is washed with a dialysis membrane to remove excess sodium hydroxide and to obtain polyethyleneimine crystal powder. The concentration of sodium hydroxide to be used may be in the range of 1 to 10 mol / L, and is preferably in the range of 3 to 5 mol / L in order to perform a more efficient reaction. The reaction temperature is preferably around 80 ° C.

  In the hydrolysis under acidic conditions or alkaline conditions, the amount of acid or alkali used may be 1 to 10 equivalents relative to the oxazoline unit in the polymer. In order to improve reaction efficiency and simplify post-treatment. About 3 equivalents are preferred.

  By the hydrolysis, a linear skeleton composed of polyoxazolines in the precursor polymer becomes a linear polyethyleneimine skeleton, and a polymer having the polyethyleneimine skeleton is obtained.

  In the case of forming a block copolymer of a linear polyethyleneimine block and another polymer block, the precursor polymer is a block copolymer composed of a linear polymer block composed of polyoxazolines and another polymer block. And a linear block composed of polyoxazolines in the precursor polymer can be selectively hydrolyzed.

  When the other polymer block is a water-soluble polymer block such as poly (N-propionylethyleneimine), poly (N-propionylethyleneimine) is converted to poly (N-formylethyleneimine) or poly (N-acetyl). A block copolymer can be formed by taking advantage of its higher solubility in organic solvents than ethyleneimine). That is, 2-oxazoline or 2-methyl-2-oxazoline is subjected to cationic ring-opening living polymerization in the presence of the above-described polymerization initiating compound, and then 2-ethyl-2-oxazoline is further polymerized to the obtained living polymer. Thus, a precursor polymer composed of a poly (N-formylethyleneimine) block or a poly (N-acetylethyleneimine) block and a poly (N-propionylethyleneimine) block is obtained. The precursor polymer is dissolved in water, and water and an incompatible organic solvent in which the poly (N-propionylethyleneimine) block is dissolved are mixed and stirred in the aqueous solution to form an emulsion. A linear polyethyleneimine block is obtained by preferentially hydrolyzing a poly (N-formylethyleneimine) block or a poly (N-acetylethyleneimine) block by adding an acid or an alkali to the aqueous phase of the emulsion. And a block copolymer having a poly (N-propionylethyleneimine) block.

  When the valence of the polymerization initiating compound used here is 1 or 2, a linear block copolymer is obtained. When the valence is higher than that, a star-shaped block copolymer is obtained. Further, by making the precursor polymer a multistage block copolymer, the resulting polymer can also have a multistage block structure.

[Metal ion (b)]

  The metal ion (b) in the present invention forms a metal complex by coordination with the polyethyleneimine unit in the skeleton by the strong coordination ability of the polyethyleneimine skeleton in the polymer (a). The metal complex is obtained by coordination of a metal ion (b) to a polyethyleneimine unit. Unlike a process such as ionic bonding, the metal complex is complexed by coordination of polyethyleneimine regardless of whether the metal is a cation or an anion. Can be formed. Therefore, the metal species of the metal ion (b) is not limited as long as it can coordinate bond with the polyethyleneimine unit in the polymer (a), and alkali metal, alkaline earth metal, transition metal, metalloid, lanthanum series Examples include metals and metal compounds of polyoxometalates, and metal ions having these metal species can be preferably used.

Examples of the alkali metal ion include ions such as Li, Na, K, and Cs. As the counter anion of the alkali metal ion, Cl, Br, I, NO ₃ , SO ₄ , PO ₄ , ClO ₄ , PF ₆ , BF ₄ , F ₃ CSO _{3 and the} like can be suitably used.

  Examples of the alkaline earth metal ions include ions such as Mg, Ba, and Ca.

The transition metal ion may be a transition metal cation (M ^{n +} ), an acid group anion (MO _x ⁿ⁻ ) composed of a bond with oxygen, or an anion (ML _x ) composed of a halogen bond. ^{Even n-} ) can be suitably used for complex formation. In the present specification, the transition metal refers to Sc, Y in Group 3 of the periodic table, and transition metal elements in Groups 4 to 12 in the 4th to 6th periods.

Examples of transition metal cations include the following transition metal cations (M ^{n +} ), such as Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ru, Rh, Pd, and Ag. , Cd, W, Os, Ir, Pt, Au, Hg, monovalent, divalent, trivalent or tetravalent cations. The counter anion of these metal cations may be any of Cl, NO ₃ , SO ₄ , polyoxometalates anions, or organic anions of carboxylic acids. However, it is preferable to prepare a complex of Ag, Au, Pt or the like that is easily reduced by the polyethyleneimine skeleton by suppressing the reduction reaction, for example, by adjusting the pH to an acidic condition.

Examples of the transition metal anion include the following transition metal anions (MO _x ⁿ⁻ ), such as MnO ₄ , MoO ₄ , ReO ₄ , WO ₃ , RuO ₄ , CoO ₄ , CrO ₄ , VO ₃ , NiO ₄ , UO _2. Of the anion.

  As the metal ion (b) of the present invention, a metal compound of polyoxometalates in which the transition metal anion is fixed in silica via a metal cation coordinated to an ethyleneimine unit in the polymer (a) It may be a form. Specific examples of the polyoxometalates include molybdate, tungstate and vanadate in combination with a transition metal cation.

Furthermore, an anion (ML _x ⁿ⁻ ) containing the following metal, for example, AuCl ₄ , PtCl ₆ , RhCl ₄ , ReF ₆ , NiF ₆ , CuF ₆ , RuCl ₆ , In ₂ Cl ₆ , the metal is arranged on the halogen. Positioned anions can also be used favorably for complex formation.

  Further, examples of the metalloid ions include Al, Ga, In, Tl, Ge, Sn, Pb, Sb, and Bi, and Al, Ga, In, Sn, Pb, and Tl are particularly preferable.

  Examples of the lanthanum metal ions include trivalent cations such as La, Eu, Gd, Yb, and Eu.

[Silica (c)]
As the silica (c) in the composite material of the present invention, a silica obtained by a known and usual sol-gel reaction of a silica source can be used.

[Silica / metal complex composite]
The composite material of the present invention is a composite in which a metal complex in which at least one metal ion (b) is coordinated to a polymer (a) having a linear polyethyleneimine skeleton is coated with silica (c). The material is characterized by having various shapes.

  The shape of the composite material of the present invention is based on a fiber shape (hereinafter referred to as a primary structure) having a thickness of about several to several hundred nm, preferably 15 to 100 nm. The composite material of the invention can express various shapes by the association of the primary structures including the shape of the primary structures. The length of the fiber shape as the primary structure is not particularly limited, but is preferably in the range of 0.1 μm to 3 mm.

  In the primary structure, the metal ion (b) is coordinated with the polymer (a) to form a complex, so that it is considered that the metal complex is present in the tubular silica.

  The composite material of the present invention can form an aggregate having a two-dimensional or three-dimensional spatial shape (hereinafter referred to as a secondary structure) in the order of micro to millimeter by the association of the primary structures. The secondary structure of the aggregate can be adjusted to various shapes such as lettuce, fiber, sponge, aster, cactus, and dandelion. These shapes depend on the geometric shape of the structure of the polymer (a), the molecular weight, the non-ethyleneimine moiety that can be introduced into the polymer (a), and the crystal formation conditions of the polymer (a). Yes, it is particularly affected by the molecular structure, degree of polymerization, composition and polymer crystal preparation method of the polymer (a) used.

  Further, the above-mentioned secondary structure aggregates or the secondary structure aggregates are bonded through a primary structure to form a macro hierarchical structure (hereinafter referred to as a tertiary structure) having a size of millimeter order or more. be able to. The tertiary structure can be formed into an arbitrary shape, and is formed into a disk shape, a column shape, a plate shape, a filter shape, a membrane shape, a spherical shape, a rod shape, etc., according to specific application requirements. be able to.

  As described above, since the composite material of the present invention can have various shapes, it can be processed into various states such as powder, particles, polyhedron, and cylinder.

  The content of silica (c) in the composite material of the present invention is not particularly limited as long as the primary, secondary, and tertiary structures can be formed, but the above structures are stable when the content is in the range of 30 to 80% by mass. Since it can form, it is preferable. Moreover, content of a metal ion (b) can be suitably adjusted according to various uses.

  As described above, since the composite material of the present invention has a metal complex inside and can be molded into various shapes, it can be formed into various areas of nanotechnology, for example, nanometal catalysts, nanometal conductive materials. Wide application can be expected as nano metal color materials, nano metal sensors, and medical materials.

[Method for producing silica / metal complex composite material]
In order to produce the composite material of the present invention, it is considered essential to control the shape of silica and the presence of coordination molecules capable of concentrating metal ions inside the silica. In the production method of the present invention, using a polymer having a linear polyethyleneimine skeleton as the coordinating molecule, (1) a polymer having a linear polyethyleneimine skeleton is associated to form various shapes, Silica is fixed by advancing a sol-gel reaction on the surface of the aggregate of the polymer, and (2) metal ions are highly concentrated by a polymer having a linear polyethyleneimine skeleton present in the silica, and the metal ions and By forming the complex in situ, it is possible to realize a composite material containing the metal complex inside and capable of shape control.

  In the above (i), the linear polyethyleneimine skeleton in the polymer having the linear polyethyleneimine skeleton is soluble in water, but exists as an insoluble aggregate at room temperature. Give the unit a template function. In addition, there are inevitably many free polyethyleneimine chains that are irrelevant to the associated structure on the surface of the polymer aggregate, and these free chains are brushed on the surface of the polymer aggregate. These brush chains are scaffolds for attracting the silica source and at the same time serve as a catalyst for polymerizing the silica source.

  Here, by causing the sol-gel reaction to proceed on the surface of the polymer aggregate having a linear polyethyleneimine skeleton, a composite of the polymer aggregate and silica in which the polymer aggregate surface is coated with silica is obtained. At this time, the shape of the polymer aggregate is copied onto silica, so that various shapes that can be induced by the polymer aggregate can be reflected in the composite of the polymer aggregate and silica.

  In addition, the polymer aggregate having a linear polyethyleneimine skeleton gives a hydrogel whose shape can be easily controlled in the presence of water. Therefore, after the hydrogel is molded into an arbitrary shape, the polymer aggregates in the hydrogel Are crosslinked by chemical bonding with a compound having two or more functional groups, and then subjected to a sol-gel reaction, whereby a polymer aggregate and silica in which the shape of each polymer aggregate is incorporated in a large mass of silica gel. To obtain a molded body of the composite. Since the hydrogel can be formed into various shapes, the composite of the polymer aggregate and silica can be controlled macroscopically.

  By bringing the complex of the polymer aggregate and silica, which can be controlled into various shapes, into contact with the aqueous metal ion solution, a large amount of the complex of the polymer aggregate and silica can be obtained by the function (ii) above. In the silica, and the metal ions form a coordination bond with the polymer having a linear polyethyleneimine skeleton in silica. And a metal complex is formed.

As a specific method for producing the composite material of the present invention, the following steps (1) to (3):
(1) a step of associating a polymer having a linear polyethyleneimine skeleton in an aqueous medium;
(2) a step of obtaining a composite of the polymer aggregate and silica by adding alkoxysilane to the polymer aggregate in the presence of an aqueous medium;
(3) A step of impregnating a complex of the polymer aggregate and silica with a solution in which metal ions are dissolved to coordinate the metal ions to the linear polyethyleneimine skeleton in the polymer.
The manufacturing method which has this.

[Process for associating polymers]
In the production method of the present invention, first, (1) a linear polyethyleneimine skeleton that becomes a template in the shape of the composite material of the present invention by associating a polymer having a linear polyethyleneimine skeleton in an aqueous medium. An aggregate of polymers having Here, the polymer having a linear polyethyleneimine skeleton that can be used is the same as the polymer (a).

  In the polymer (a), the linear polyethyleneimine skeleton develops crystallinity in an aqueous medium and crystallizes, and the crystals associate with each other to form the polymer aggregate (d). . The polymer aggregate (d) can be made into a hydrogel having a three-dimensional network structure by physical bonding between the polymer aggregates (d) in the presence of water, and the polymer aggregates can be further cross-linked with each other. It can also be set as the crosslinked hydrogel which has a chemical crosslink by crosslinking | crosslinking by. These hydrogel-like polymer aggregates (d) can easily adjust the secondary structure of the composite material obtained by adjusting the preparation conditions of the hydrogel, and can form a macro tertiary structure of the composite material. Since shape control is easy, it is preferable.

  Polyethyleneimine that has been widely used heretofore is a branched polymer obtained by ring-opening polymerization of cyclic ethyleneimine, and a primary amine, secondary amine, and tertiary amine are present in the structural unit. Therefore, branched polyethyleneimine is water-soluble, but has no crystallinity. Therefore, in order to make a hydrogel using branched polyethyleneimine, a network structure must be provided by covalent bonding with a crosslinking agent. However, the linear polyethyleneimine that the polymer used in the present invention has as a skeleton is composed only of a secondary amine, and the secondary amine type linear polyethyleneimine is water-soluble and has excellent crystallinity. / Has association properties.

  Such linear polyethyleneimine crystals are known to vary greatly in the structure of the polymer crystallized depending on the number of water of crystallization contained in the ethyleneimine unit of the polymer (Y. Chatani et al. , Macromolecules, 1981, Vol. 14, pp. 315-321). Anhydrous polyethylenimine prefers a crystal structure characterized by a double helix structure, but if the monomer unit contains two molecules of water, the polymer is known to grow into a crystal characterized by a zigzag structure. Yes. Actually, the crystal of linear polyethyleneimine obtained from water is a crystal containing bimolecular water in one monomer unit, and the crystal is insoluble in water at room temperature.

  The polymer aggregate (d) in the present invention is formed by crystal expression of a linear polyethyleneimine skeleton in the same manner as described above, and the polymer structure has a linear, star, or comb structure. Even if it is a polymer having a linear polyethyleneimine skeleton, a polymer aggregate (d) is obtained. That is, the polymer aggregate (d) in the present invention is grown from polymer crystal formation.

  The fact that the polymer aggregate in the present invention has a crystal structure can be confirmed by X-ray scattering, and the linear chain in the crystalline hydrogel of 20 °, 27 °, and 28 ° in the 2θ angle value in a wide angle X-ray diffractometer (WAXS). It is confirmed by the peak value derived from the polyethylene-imine skeleton.

  Moreover, although the melting point in the differential scanning calorimeter (DSC) of the polymer aggregate (d) in the present invention depends on the structure of the polymer constituting the aggregate, the melting point generally appears at 45 to 90 ° C.

  The polymer aggregate (d) in the present invention is formed of the geometric shape of the polymer structure constituting the aggregate, the molecular weight, the non-ethyleneimine moiety that can be introduced into the primary structure, and the formation of the polymer aggregate (d). Various shapes can be obtained due to the influence of conditions and the like, and for example, it has a fiber shape, a brush shape, a star shape, or the like.

  The polymer aggregate (d) is based on a fibrous polymer crystal of nanometer order of about 3 to 30 nm (hereinafter, the crystal is abbreviated as a fibrous nanocrystal). With the free ethyleneimine chain existing on the surface of the fibrous nanocrystal, the fibrous nanocrystals are connected to each other by a physical bond by hydrogen bonding and arranged in a space. d) grow. These polymer aggregates (d) can be further physically bonded to form a crosslinked structure, thereby forming a three-dimensional network structure of the polymer aggregates (d). Since these occur in an aqueous medium, it is possible to give a hydrogel of a polymer aggregate (d) including water in the three-dimensional network structure.

  The three-dimensional network structure here is different from ordinary polymer hydrogel, and micro or nano-scale aggregates are physically cross-linked by hydrogen bonds of free ethyleneimine chains existing on the surface of the aggregate. Say a structured network. Therefore, at a temperature equal to or higher than the melting point of the aggregate, the aggregate is dissolved in water, and the three-dimensional network structure is disassembled. However, when it returns to room temperature, polymer aggregates grow, and physical crosslinks due to hydrogen bonds are formed between the aggregates, so that a three-dimensional network structure appears again.

  The polymer aggregate (d) utilizes the property that the polymer having a linear polyethyleneimine skeleton is insoluble in water at room temperature, so that the polymer having the linear polyethyleneimine skeleton is dissolved in the water and converted into an aggregate. Can be obtained.

  In the hydrogel of the polymer aggregate (d), the polymer (a) is first dispersed in water, and the dispersion is heated to obtain a transparent aqueous solution of the polymer (a). Subsequently, it is obtained by cooling the aqueous solution of the polymer (a) in a heated state to room temperature. The hydrogel of the polymer aggregate (d) is deformed by an external force such as a shearing force, but has a state capable of maintaining a general shape and can be deformed into various shapes. The composite material of the present invention can be molded into various shapes.

  The heating temperature of the polymer dispersion is preferably 100 ° C. or less, and more preferably in the range of 90 to 95 ° C. Further, the content of the polymer (a) in the polymer dispersion is not particularly limited as long as the hydrogel of the polymer aggregate (d) is obtained, but may be in the range of 0.01 to 20% by mass. Preferably, the range of 0.1 to 10% by mass is more preferable in order to obtain a hydrogel of the polymer aggregate (d) having a stable shape. Thus, in the present invention, when the polymer (a) is used, the hydrogel can be formed even with a very small concentration of polymer.

  The shape of the polymer aggregate (d) in the resulting hydrogel can be adjusted by the process of lowering the temperature of the aqueous polymer solution to room temperature. As a method for obtaining a hydrogel, for example, an aqueous polymer solution is kept at 80 ° C. for 1 hour, then brought to 60 ° C. over 1 hour, and kept at that temperature for another hour. Thereafter, the temperature is lowered to 40 ° C. over 1 hour, and then naturally lowered to room temperature, whereby the water in the aqueous solution becomes a hydrogel in which the fluidity is lost. In addition, after cooling the above aqueous polymer solution at once with freezing water, or methanol / dry ice below freezing point, or a refrigerant liquid of acetone / dry ice, the state in that state is held in a water bath at room temperature, Furthermore, the hydrogel can be obtained also by a method of lowering the temperature of the polymer aqueous solution to room temperature in a water bath or room temperature air environment at room temperature.

  Since the step of lowering the temperature of the aqueous polymer solution strongly affects the shape of the polymer aggregate (d) in the resulting hydrogel, the form of the polymer aggregate (d) in the hydrogel obtained by the different methods is the same. is not.

  When the temperature of the polymer aqueous solution is lowered in a multistage manner with a constant concentration, the form of the polymer aggregate (d) in the hydrogel can be made into a fiber form. When this is rapidly cooled and then returned to room temperature, it can be in the form of a petal. Moreover, when this is rapidly cooled again with acetone on dry ice and returned to room temperature, it can be made into a wavy form. Thus, in this invention, the form of the polymer aggregate (d) in the hydrogel can be set to various shapes.

  The hydrogel of the polymer aggregate (d) obtained as described above is an opaque gel, and a polymer aggregate having a polyethyleneimine skeleton is formed in the gel and is physically crosslinked by hydrogen bonding between the aggregates. And form a three-dimensional physical network structure. The polymer aggregate (d) in the hydrogel once formed remains insoluble at room temperature, but when heated, the polymer aggregate (d) is dissociated and the hydrogel changes to a sol state. Therefore, the physical hydrogel in the present invention can be reversibly changed from sol to gel and from gel to sol by heat treatment.

  The hydrogel of the polymer aggregate (d) mentioned here contains at least water in the three-dimensional network structure, and a hydrogel containing an organic solvent can be obtained by adding a water-soluble organic solvent during the preparation of the hydrogel. . Examples of the hydrophilic organic solvent include water-soluble organic solvents such as methanol, ethanol, tetrahydrofuran, acetone, dimethylacetamide, dimethylsulfone oxide, dioxirane, and pyrrolidone. The content of the organic solvent is preferably in the range of 0.1 to 5 times the volume of water, more preferably in the range of 1 to 3 times.

  By containing the hydrophilic organic solvent, the form of the polymer aggregate (d) can be changed, and an aggregate having a form different from that of a simple aqueous system can be provided. For example, even in the form of a branched aggregate having a fiber-like spread in water, when a certain amount of ethanol is included in the preparation, a spherical aggregate form in which fibers are contracted can be obtained.

  In preparing the polymer aggregate (d) from the water-soluble organic solvent, when the polymer (a) is easily dissolved in the organic solvent, the polymer (a) is dissolved in the organic solvent and then water is added to the solution. Thus, the polymer aggregate (d) can be obtained. In such a process, heat fixation can be eliminated.

  Further, when preparing the polymer aggregate (d) from the organic solution of the polymer (a), an organic compound having an acidic group is mixed in the organic solution, and water is added thereto, whereby the intermolecular relationship between the polyethyleneimine and the acid is increased. These complexes can be obtained simultaneously with the formation of the complex.

  Any organic compound having an acidic group may be used as long as it has an acidic group that can be easily bonded to polyethyleneimine, such as carboxylic acid, sulfonic acid, and phosphoric acid, and a compound having a large number of acidic groups in one molecule may also be used. Can do.

  As such a compound having an acidic group, a dye compound having a special function is particularly preferable. Among these, for example, porphyrin dyes, phthalocyanine dyes, and azo dyes can be suitably used.

  A hydrogel containing a water-soluble polymer can be obtained by adding another water-soluble polymer during the preparation of the hydrogel. Examples of the water-soluble polymer include polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, poly (N-isopropylacrylamide), polyhydroxyethyl acrylate, polymethyloxazoline, polyethyloxazoline, and the like.

  The content of the water-soluble polymer is preferably in the range of 0.1 to 5 times, more preferably in the range of 0.5 to 2 times the mass of the polymer having a linear polyethyleneimine skeleton.

  By containing the water-soluble polymer, the form of the polymer aggregate (d) can be changed, and an aggregate having a form different from that of a simple aqueous system can be provided. It is also effective in increasing the viscosity of the hydrogel and improving the stability of the hydrogel.

  Further, the surface of the polymer aggregate (d) in the hydrogel is linked with chemical bonds by treating the hydrogel obtained by the above method with a compound containing two or more functional groups that react with the amino group of polyethyleneimine. A crosslinked hydrogel having a macro structure immobilized thereon can be obtained.

  As the compound containing at least two functional groups capable of reacting with the amino group at room temperature, aldehyde crosslinking agents, epoxy crosslinking agents, acid chlorides, acid anhydrides, and ester crosslinking agents can be used. Examples of the aldehyde crosslinking agent include malonyl aldehyde, succinyl aldehyde, glutaryl aldehyde, adifoyl aldehyde, phthaloyl aldehyde, isophthaloyl aldehyde, terephthaloyl aldehyde, and the like. Examples of the epoxy crosslinking agent include polyethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, glycidyl chloride, and glycidyl bromide. Examples of the acid chlorides include malonyl chloride, succinyl chloride, glutaryl chloride, adifoyl chloride, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, and the like. Examples of the acid anhydride include phthalic anhydride, succinic anhydride, and glutaric anhydride. Examples of the ester crosslinking agent include malonic acid methyl ester, succinic acid methyl ester, glutaric acid methyl ester, phthaloyl acid methyl ester, and polyethylene glycol carboxylic acid methyl ester.

  The cross-linking reaction can be carried out by immersing the obtained hydrogel in a solution of the cross-linking agent or by adding the cross-linking agent solution into the hydrogel. At this time, the cross-linking agent permeates into the hydrogel along with the osmotic pressure change in the system, where the polymer aggregates are connected by hydrogen bonds to cause a chemical reaction with the nitrogen atom of ethyleneimine.

  The crosslinking reaction proceeds by a reaction with free ethyleneimine on the surface of the polymer aggregate (d), but in order to prevent the reaction from occurring inside the aggregate, the melting point of the aggregate forming the hydrogel is lower than the melting point. It is desirable to carry out the reaction at a temperature of 2 ° C., and it is most desirable to carry out the crosslinking reaction at room temperature.

  When the crosslinking reaction proceeds at room temperature, the crosslinked hydrogel can be obtained by leaving the hydrogel mixed with the crosslinking agent solution. The time for the crosslinking reaction may be from a few minutes to a few days, and the crosslinking proceeds suitably by leaving it to stand overnight.

  The amount of the crosslinking agent may be 0.05 to 20% with respect to the number of moles of the ethyleneimine unit in the polymer (a) used for forming the hydrogel, and more preferably 1 to 10%.

  By the method described above, the polymer aggregate (d) can be obtained by associating the polymer (a). Further, by using the polymer aggregate (d) in a hydrogel state, it is possible to express gel structures having various morphologies. The polymer (a) used here is easy to design and synthesize, and easy to adjust the hydrogel. Moreover, the shape of a hydrogel can also be fixed by bridge | crosslinking between the polymer aggregates (d) in this hydrogel with a crosslinking agent.

[Step of obtaining silica / polymer composite]
In the production method of the present invention, subsequent to the step (1), (2) in the presence of an aqueous medium, the polymer aggregate (d) obtained in the above (1) is added to the alkoxysilane to add the above polymer. A step of obtaining a complex of the aggregate (d) and silica (c) (hereinafter abbreviated as silica / polymer complex (e)).

  In the silica / polymer composite (e), a silica source was dissolved in a solvent that can be used in a normal sol-gel reaction in a dispersion in water of the polymer aggregate (d) or a hydrogel of the polymer aggregate (d). It can be easily obtained by adding a solution and causing a sol-gel reaction at room temperature.

  Examples of the compound used as the silica source include tetraalkoxysilanes and alkyltrialkoxysilanes.

  Examples of tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and tetra-t-butoxysilane.

  Examples of alkyltrialkoxysilanes include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, iso-propyltrimethoxysilane, iso -Propyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycitoxypropyltrimethoxysilane, 3-glycitoxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltomethoxysilane, 3-mercaptotriethoxysilane, 3,3,3-trifluoropropylto Methoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxylane, p-chloromethylphenyltrimethoxy Orchid, p-chloromethylphenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxycyan and the like.

  The sol-gel reaction that gives the silica / polymer composite (e) proceeds in the presence of the polymer aggregate (d) in the aqueous medium, but the reaction does not occur in the aqueous medium phase, and the polymer aggregate (d) Progress on the surface. Accordingly, the reaction conditions are arbitrary as long as the polymer aggregate (d) is not dissolved under the complexing reaction conditions.

  In order to make the polymer aggregate (d) insoluble, the presence of water is preferably 20% or more in an aqueous liquid containing a hydrophilic organic solvent in the sol-gel reaction, and if it is 40% or more, Further preferred.

  In the sol-gel reaction, the silica / polymer composite (e) can be suitably formed if the amount of alkoxysilane as a silica source is excessive with respect to ethyleneimine as a monomer unit of polyethyleneimine. The degree of excess is preferably in the range of 4 to 1000 times equivalent to ethyleneimine.

  The polymer concentration in the aqueous medium when forming the polymer aggregate (d) is preferably 0.1 to 30% based on the amount of polyethyleneimine contained in the polymer.

  The sol-gel reaction time varies from 1 minute to several days. In the case of methoxysilanes having a high alkoxysilane reaction activity, the reaction time may be from 1 minute to 24 hours. It is more preferable to set it to 30 minutes to 5 hours. In the case of ethoxysilanes and butoxysilanes having low reaction activity, the sol-gel reaction time is preferably 24 hours or longer, and it is also desirable to set the time to about one week.

  The silica / polymer composite (e) has various shapes, and the shape is an enlarged copy of the aggregate shape derived from the polymer aggregate (d). Therefore, before the sol-gel reaction, the shape of the silica / polymer composite (e) can be controlled by first growing the polymer aggregate (d) in water or an aqueous medium and adjusting the shape of the polymer aggregate (d). . Preparation of the polymer aggregate (d) and the hydrogel derived from the polymer aggregate (d) in water or an aqueous liquid is as described above.

  The shape of the silica / polymer composite (e) obtained can be adjusted to various three-dimensional shapes such as lettuce, fiber, sponge, aster, cactus, dandelion, and sphere. The size of these silica / polymer composites (d) can be of the order of 3 μm to 1 mm on the order of micrometers, but the shape of this size is a fiber with a thickness of 15 to 100 nm that is regarded as a basic unit. It is a three-dimensional shape formed from the association and spatial arrangement of a silica / polymer composite (e) in the form of a glass. The fibrous silica / polymer composite (e) having a thickness of 15 to 100 nm serving as the basic unit includes a core of about 3 to 30 nm, and the core is a polymer fibrous nanocrystal having a linear polyethyleneimine skeleton. It is. That is, the three-dimensional shape of the micrometer order is based on the shape of the polymer aggregate (d) in which the fibrous nanocrystals are connected in water by physical bonds by hydrogen bonds in water. Various shapes that can be taken by the polymer aggregate (d) become a template of a three-dimensional shape, and silica is fixed along the template, whereby a fibrous shape having a thickness of 15 to 100 nm is obtained. It is considered that the silica / polymer composite (e) is associated with each other to form a spatial shape.

  These shapes are adjusted according to the geometric shape of the structure of the polymer (a), the molecular weight, the non-ethyleneimine moiety that can be introduced into the primary structure, and the formation conditions of the polymer aggregate (d) as described above. It depends well on the molecular structure of the polymer used, the degree of polymerization, the composition, and the method of temperature reduction during the preparation of the polymer aggregate (d).

  For example, a linear polyethyleneimine having a degree of polymerization of 300 or more is used as the polymer (a), and the polymer aggregate (d) is obtained by naturally lowering the temperature from 80 ° C. or higher to room temperature. A silica / polymer composite (e) having a lettuce-like three-dimensional shape can be obtained by subjecting a silica source to a sol-gel reaction using (d). In the lettuce-like silica / polymer composite (e), the thickness of the portion forming the leaf increases as the concentration when the polymer (a) is crystallized decreases, but at a concentration of 2% or more, the leaf portion The thickness is around 100 nm, and when the concentration is 1% or less, the thickness of the leaf portion is around 500 nm.

  In the case of using star-shaped polyethyleneimine, the shape of the resulting silica / polymer composite (e) can also be controlled by changing the structure of the central residue serving as the nucleus. For example, when the central residue has a large pi plane such as porphyrin, the three-dimensional shape of the resulting silica / polymer composite (e) is an aster, and the size of one aster-shaped aggregate Is about 2 to 6 μm. When the concentration is 1% or more, the number of aster arms is small and each arm tends to bind, and when the concentration is less than that, the number of arms is large and each arm tends to separate. Further, when the central residue is a small structure such as a benzene ring, the resulting silica / polymer composite (e) is in the form of a fiber in which many yarns are bound, and the fibers are entangled with each other, resulting in a sponge-like structure as a whole. Form a three-dimensional shape. The thickness of one fiber-shaped aggregate is around 150 nm.

  Further, the silica / polymer composites (e) having various three-dimensional shapes formed from the association and spatial arrangement of the fibrous silica / polymer composites (e) are further bonded to each other to have a size of millimeter order or more. It is also possible to form a silica / polymer composite (e) having a macro shape of This is because polymer nanocrystals of a polymer having a linear polyethyleneimine skeleton in water or in an aqueous liquid are connected in water by physical bonds by hydrogen bonds in water, and polymer aggregates of various shapes (d) Then, the polymer aggregates (d) form a three-dimensional network structure by further physical bonding, and this is immobilized with silica (c), whereby a silica / polymer composite having a three-dimensional shape is obtained. (E) It has a form in which they are associated with each other.

  Further, by using a crosslinked hydrogel in which the polymer aggregates (d) are crosslinked by chemical bonds, the macro shape of the silica / polymer composite (e) is controlled, and the silica / polymer composite (e) is formed in various shapes. It can also be set as a molded body. The shape and size can be made the same as the size and shape of the container used at the time of preparing the crosslinked hydrogel, and for example, it can be prepared in any shape such as a disk shape, a cylindrical shape, a plate shape, and a spherical shape. Further, the crosslinked hydrogel can be cut or scraped to be formed into a desired shape. By immersing the crosslinked hydrogel formed in this manner in a silica source solution, a molded body composed of a silica / polymer composite can be easily obtained. The time for soaking in the silica source solution varies from 1 hour to 1 week depending on the type of silane source to be used. Therefore, it is necessary to prepare it appropriately. However, in the solution of methoxysilanes, it may be about 1 to 48 hours. In the solution of ethoxysilanes, about 1 to 7 days is preferable.

  Usually, the silica / polymer composite (e) is composed of a polymer aggregate (d) and silica (c), and the content of silica (c) in the silica / polymer composite (e) depends on the reaction conditions. Although it changes with a fixed width | variety by etc., the thing of the range of 30-90 mass% of the whole silica / polymer composite (e) can be obtained.

  The content of silica (c) increases as the amount of polymer (a) used in the sol-gel reaction, that is, the concentration of polymer (a) in the hydrogel increases. Moreover, it increases by lengthening the sol-gel reaction time.

  The silica / polymer composite has various shapes as described above, and the shape gives the primary structure, secondary structure, and tertiary structure of the composite material of the present invention. The primary structure of the composite material of the present invention is a fibrous silica / polymer composite (e) having a thickness on the order of nanometers. The secondary structure is provided by the association of the primary structures. And a silica / polymer composite (e) in which a three-dimensional spatial shape is formed. Further, the tertiary structure is given by a macro hierarchical structure in which the primary and secondary structures are further combined, and the shape thereof can be formed by various processes as described above.

  The silica / polymer composite (e) contains fibrous nanocrystals of the polymer (a) inside the silica (c) layer, and a fluorescent substance can be incorporated into the polymer (a). For example, by using a star-shaped polyethyleneimine centered on porphyrin, the residue of porphyrin is incorporated into the silica / polymer complex (e). Further, for example, by using a polymer aggregate (d) obtained by reacting a small amount of pyrenes, for example, pyrenealdehyde (preferably, 10 mol% or less with respect to imine) on the side chain of polyethyleneimine, It can be incorporated into the silica / polymer composite (e). Furthermore, a fluorescent dye such as porphyrins, phthalocyanines, pyrenes having an acidic group, for example, a carboxylic acid group or a sulfonic acid group, is added to the base of polyethyleneimine (preferably 0.1 mol% or less based on the number of moles of imine). ) These fluorescent substances can be incorporated into the silica / polymer composite (e) obtained by mixing a small amount and using the aggregate of the mixture as a template.

[Step of obtaining silica / metal complex composite material]
In the production method of the present invention, following the step (2), (3) the silica / polymer composite (e) is brought into contact with the solution in which the metal ions are dissolved, thereby bringing the linear form in the polymer into contact. The composite material of the present invention coordinated to a polyethyleneimine skeleton can be obtained.

  Here, as a metal ion which can be used, the above-mentioned metal ion (b) can be used. The solution in which the metal ion (b) is dissolved can be prepared by dissolving a salt containing the metal ion (b) in water.

  The method for bringing the silica / polymer composite (e) into contact with the solution in which the metal ion (b) is dissolved in the step (3) is not particularly limited. For example, the method can be obtained by the step (2). A method of immersing the obtained silica / polymer composite (e) in an aqueous solution of metal ions (b) can be mentioned. By this method, the metal ion (b) can be easily concentrated in silica. Since the metal concentrated in the silica forms a coordinate bond with the polymer aggregate in the silica, the polymer aggregate (d) is disassembled in the silica, and instead a metal ion (b) is arranged in the polymer (a). Coordinated metal complexes are formed. Thereby, the composite material of the silica of this invention and a metal complex can be obtained easily.

  When the metal ion (b) is concentrated in the silica, the more the polymer (a) in the silica / polymer composite (e), the more the metal ion (b) is mixed with the polymer (a). The higher the ratio, the greater the amount of metal ion (b) concentrated in the silica. According to the present invention, 0.1 to 0.5 times the metal ion (b) forms a complex with respect to the number of moles of nitrogen atoms of the polyethyleneimine skeleton contained in the silica / polymer composite (e). Can do.

  When the silica / polymer composite (e) is immersed in an aqueous solution of the metal ion (b), the amount of the metal ion (b) is particularly preferably about 0.1 to 10 times the ethyleneimine unit. is there.

  After the metal ions (b) are taken in, the composite material can be taken out and washed with room temperature or cold water to obtain the composite material of the present invention.

  EXAMPLES Hereinafter, although an Example and a reference example demonstrate this invention further more concretely, this invention is not limited to these. Unless otherwise specified, “%” represents “mass%”.

[Analysis by X-ray diffraction method]
Place the isolated and dried sample on a measurement sample holder, set it on a Rigaku wide-angle X-ray diffractometer “Rint-Ultma”, Cu / Kα ray, 40 kV / 30 mA, scan speed 1.0 ° / min, Measurement was performed under conditions of a scanning range of 10 to 40 °.

[Analysis by differential thermal scanning calorimetry]
The isolated and dried sample was weighed with a measurement patch, set in a thermal analysis device “DSC-7” manufactured by Perkin Elmer, and heated at a rate of 10 ° C./min in a temperature range of 20 ° C. to 90 ° C. Measurements were made.

[Shape analysis by scanning electron microscope]
The isolated and dried sample was placed on a glass slide and observed with a surface observation device VE-7800 manufactured by Keyence Corporation.

[Observation with transmission electron microscope]
The isolated and dried sample was placed on a carbon-deposited copper grid, and it was placed on Topcon Co., Ltd., EM-002B manufactured by Nolan Instruments, VOYAGER M3055 high-resolution transmission electron microscope, or JEOL Co. transmission type Observation was performed with an electron microscope “JEM-200CX”.
[UV-Vis absorption spectrum] A silica powder containing a metal complex was placed on a quartz glass plate and measured with U-3500 UV-Vis manufactured by Hitachi, Ltd. equipped with an integrating sphere.

(Synthesis Example 1)
[Synthesis of Silica / Linear Polyethyleneimine Complex (SLP-1)]
<Synthesis of linear polyethyleneimine (L-PEI)>
3 g of commercially available polyethyloxazoline (number average molecular weight 50000, average polymerization degree 5000, manufactured by Aldrich) was dissolved in 15 mL of 5M aqueous hydrochloric acid. The solution was heated to 90 ° C. in an oil bath and stirred at that temperature for 10 hours. Acetone 50 mL was added to the reaction solution to completely precipitate the polymer, which was filtered and washed with methanol three times to obtain white polyethyleneimine powder. When the obtained powder was identified by ¹ H-NMR (heavy water), peaks 1.2 ppm (CH ₃ ) and 2.3 ppm (CH ₂ ) derived from the side chain ethyl group of polyethyloxazoline completely disappeared. It was confirmed that That is, it was shown that polyethyloxazoline was completely hydrolyzed and converted to polyethyleneimine.

  The powder was dissolved in 5 mL of distilled water, and 50 mL of 15% aqueous ammonia was added dropwise to the solution while stirring. The mixture was allowed to stand overnight, and then the precipitated polymer aggregate powder was filtered, and the polymer aggregate powder was washed three times with cold water. The crystal powder after washing was dried at room temperature in a desiccator to obtain linear polyethyleneimine (L-PEI). The yield was 2.2 g (including crystal water). In polyethyleneimine obtained by hydrolysis of polyoxazoline, only the side chain reacts and the main chain does not change. Therefore, the polymerization degree of L-PEI is the same as 5000 before hydrolysis.

<Silica composite from linear polyethyleneimine system>
A certain amount of the L-PEI powder obtained above was weighed and dispersed in distilled water to prepare an L-PEI dispersion having a concentration of 3%. These dispersions were heated to 90 ° C. in an oil bath to obtain a completely transparent aqueous solution, and then the aqueous solution was allowed to stand at room temperature and naturally cooled to room temperature to obtain an opaque L-PEI aggregate hydrogel. It was.

  As a result of X-ray diffraction measurement for the obtained aggregate, it was confirmed that peaks of scattering intensity appeared at 20.7 °, 27.6 °, and 28.4 °. Moreover, the endothermic peak was confirmed at 64.7 ° C. from the measurement result of the endothermic state change by the calorimeter. From these measurement results, the presence of L-PEI crystals in the hydrogel was confirmed.

  5 mL of a mixture of tetramethoxysilane (TMSO) and ethanol (1/1 by volume) is added to 5 mL of the hydrogel of the L-PEI aggregate obtained above, and the mixture is gently stirred for 1 minute, and then left for 40 minutes. did. Then, it wash | cleaned with excess acetone and performed it 3 times with the concentric separator. The solid was collected and dried at room temperature to obtain a composite of silica and L-PEI (SLP-1). From the X-ray diffraction measurement of the complex (SLP-1), scattering diffraction peaks appeared at 20.5 °, 27.2 °, and 28.2 °. Further, from the DSC measurement, a melting point derived from the PEI crystal appeared at 84 ° C. From the results of elemental analysis, the content of nitrogen atoms contained in silica was 8.93%. That is, the number of moles of nitrogen in 1 gram silica is 6.38 mmol.

  When the obtained composite (SLP-1) was observed with a scanning electron microscope and a transmission electron microscope, it was revealed that the composite (SLP-1) was formed from a large number of nanofibers (FIG. 1). And FIG. 2).

Example 1
<Silica / copper complex composite material>
50 mg (nitrogen 0.319 mmol) of the complex (SLP-1) obtained as described above was weighed and added to 5 mL of an aqueous copper nitrate solution (2 mM). The white silica polymer composite in the mixture turned blue. The mixture was allowed to stand for 3 hours, then filtered, washed three times with distilled water, and then dried to obtain a blue silica / copper complex composite powder.

  As a result of measuring the blue silica / copper complex composite powder with the absorption spectrum, strong absorption of the complex formed by the copper-nitrogen (Cu-N) coordination appeared at 303 nm and 630 nm.

(Example 2)
<Silica / sodium complex composite material>
50 mg (0.319 mmol) of the complex (SLP-1) obtained above was weighed and added to 5 mL of an aqueous solution of sodium triflate NaSO ₃ CF ₃ (2 mM). The mixture was allowed to stand for 3 hours, then filtered, washed 3 times with distilled water, and then dried to obtain a silica / sodium complex composite powder.

  From the WAXS measurement of the silica / sodium complex composite powder after drying, the diffraction pattern derived from L-PEI in the composite (SLP-1) disappears, and instead, the diffraction pattern is at 21 °, 32 °, and 37 °. Appeared. From the DSC observation, the melting point appeared at 169 ° C. From this, it was shown that the complex of L-PEI and sodium ion was formed in silica.

It is a scanning electron micrograph of the composite_body | complex in the synthesis example of this invention. It is a transmission electron micrograph of the composite_body | complex in the synthesis example of this invention.

Claims (11)

A composite material in which a metal complex in which at least one metal ion (b) is coordinated to a polymer (a) having a linear polyethyleneimine skeleton is coated with silica (c). The composite material according to claim 1, wherein the polymer (a) having a linear polyethyleneimine skeleton is a chain, star, or comb polymer. The composite material according to claim 1 or 2, wherein the polymer (a) having a linear polyethyleneimine skeleton is composed of a block copolymer of a linear polyethyleneimine block and another polymer block. The composite material according to any one of claims 1 to 3, wherein a ratio of the polyethyleneimine skeleton in the polymer (a) having the linear polyethyleneimine skeleton is 40 mol% or more. The metal ion (b) is at least one metal ion selected from alkali metal ions, alkaline earth metal ions, transition metal ions, metalloid ions, lanthanum metal ions, and polyoxometalates. The composite material in any one of 1-4. The composite material according to any one of claims 1 to 5, wherein the content of silica (c) is in the range of 30 to 80 mass%. The composite material according to any one of claims 1 to 6, which has a nanofiber shape with a thickness in a range of 15 to 100 nm. Nanofibers having a thickness in the range of 15 to 100 nm, in which silica (c) is coated with a metal complex in which at least one metal ion (b) is coordinated to a polymer (a) having a linear polyethyleneimine skeleton, are associated. The composite material according to any one of claims 1 to 6. The composite material according to any one of claims 1 to 6, wherein the nanofiber aggregate according to claim 8 is bonded to each other. The manufacturing method of the composite material which has the following processes.
(1) a step of associating a polymer having a linear polyethyleneimine skeleton in an aqueous medium;
(2) a step of obtaining a composite of the polymer aggregate and silica by adding alkoxysilane to the polymer aggregate in the presence of an aqueous medium;
(3) A step of impregnating a complex of the polymer aggregate and silica with a solution in which metal ions are dissolved to coordinate the metal ions to the linear polyethyleneimine skeleton in the polymer. The method for producing a composite material according to claim 10, wherein the alkoxysilane is one or two selected from the group consisting of tetraalkoxysilanes and trialkoxyalkylsilanes.