JP4469002B2 - Structure coated with superhydrophobic nanostructure composite and its production method - Google Patents

Description

  In the present invention, a solid substrate surface having an arbitrary shape is densely coated with a nanostructure formed by combining a polymer having a polyethyleneimine skeleton and silica in a nanometer order, and a hydrophobic group is formed on the nanostructure surface. The present invention relates to a structure coated with a superhydrophobic nanostructure composite, and a method for producing the structure. In addition, the polymer having a polyethyleneimine skeleton in the nanostructure is removed, and the surface is covered with a superhydrophobic nanostructure composite in which a hydrophobic group is bonded to the surface of the nanostructure mainly composed of silica. And a method of manufacturing the structure.

  It is defined as superhydrophobic when a water droplet contacts with a solid surface and the contact angle of the water droplet is 150 ° or more. The range where the contact angle is 70 to 150 ° is defined as hydrophobic. In general, hydrophobicity is expressed by covering a surface with molecular residues having a low surface tension, but superhydrophobicity is difficult to express only with molecular residues having a low surface tension.

  On the other hand, many organisms in the natural world show superhydrophobicity. For example, leaves such as lotus, rice and cabbage have super water repellency that completely repels water droplets. For example, it is known that the super water repellency of a lotus leaf is closely related to the surface structure of the leaf. That is, the surface layer is formed while the nanofibers are spread over the entire surface, and micron-sized protrusions such as nanofiber aggregates are formed on the outermost surface layer at a certain distance. It is known that hydrophobic wax exists on the surface. This suggests that the control of the surface roughness, that is, the surface structure / shape in the nano-dimension is the most important for developing the superhydrophobicity.

  The structural principle of superhydrophobic expression, also referred to as the effect of lotus, has become a guideline for the development of many artificial lotus-like structural design methods, and with the progress of nanomaterials, a number of various superhydrophobic materials have been developed in recent years. I came. For example, it has been reported that the contact angle is increased to 170 ° or more by regularly arranging carbon nanotubes on the surface of the substrate (see Non-Patent Document 1). It has also been reported that polypyrrole nanofibers are grown on a platinum-coated silicon surface by an electrochemical process to increase the surface contact angle to 170 ° or more (see Non-Patent Document 2). In addition, after forming a zinc oxide nanocrystal seeds film on the surface of the glass substrate at a temperature of 400 ° C. or higher, an infinite number of rod-shaped zinc oxide nanofibers are grown on the glass substrate surface, thereby increasing superhydrophobicity. It is expressed (see Non-Patent Document 3).

  As a simple method, for example, a certain poor solvent is added to a solution of polypropylene, and it is cast on the surface of a substrate, and the temperature is adjusted, thereby forming a network structure composed of polypropylene nanoparticles, and thereby a contact angle. Has been reported to be increased to 160 ° (Non-Patent Document 4). In addition, a glass composed of oxides of silicon, boron, and sodium has a phase separation structure, and it is further etched by chemical treatment to induce a concavo-convex structure on the surface, and finally a fluorine compound is applied to the surface. Superhydrophobicity can be expressed by reacting (see Patent Document 1). Furthermore, after producing a laminated film of polyarylamine and polyacrylic acid, the surface is treated with a chemical method to induce a surface porous structure, and silica nanoparticles are fixed thereon, and finally a fluorine alkyl residue is finally obtained. It is also known to construct a superhydrophobic boundary surface by hydrophobizing with a silane coupling agent having a group (see Patent Document 2).

  Among the methods proposed above, in the case of a superhydrophobic surface based on an inorganic material, the process of producing the surface roughness provided with the nanostructure is complicated and expensive. Further, in the case of a superhydrophobic surface based on an organic polymer, the cost is low, but the solvent resistance and corrosion resistance of the obtained superhydrophobic surface are low, which causes a practical problem.

  While it is a prerequisite for the development of superhydrophobicity, it is necessary to construct a nanostructure composite surface in which micro-sized domains are scattered over the entire surface while the fiber-like nanostructure covers the substrate surface densely. There is still a lot of exploration about what materials, and what methods are used to build nanostructured composite surfaces. In particular, even if the contact angle is temporarily high and exhibits superhydrophobicity, the superhydrophobicity often disappears when immersed in water for a long time. Therefore, the development of materials that exhibit semipermanent or permanent superhydrophobicity (superwater repellency) even when immersed in water is a challenging task.

Sun et al. , Acc. Chem. Res. 2005, 38, 644-652. Li et al. , J .; Mater. Chem. , 2008, 18, 2276-2280 Feng et al. , J .; Am. Chem. Soc. , 2004, 126, 62-63 Erbil et al. , Science, 2003, 299, 1377-1380 Special table 2008-508181 US Patent Application Publication No. 2006/029808

  In view of the above circumstances, the problem to be solved by the present invention is to provide a structure in which semipermanent superhydrophobicity is expressed on a solid substrate of an arbitrary shape, and a simple and efficient manufacturing method thereof. It is in.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a nanostructure formed by combining an organic polymer and an inorganic silica in nanometer order spreads over the entire surface of the substrate. After obtaining a structure that forms a nanostructure with a complex structure on the substrate as a film that completely covers the substrate, the surface is hydrophobized to form a superhydrophobic surface. The present inventors have found that a structure having the same can be obtained, and have completed the present invention.

  That is, the present invention is a structure in which the surface of a solid substrate is coated with a superhydrophobic nanostructure composite, and the superhydrophobic nanostructure composite comprises a polymer having a polyethyleneimine skeleton and silica. A super-hydrophobic surface, characterized in that the structure is a composite comprising a structure in which a hydrophobic group is bonded to the silica in a structure obtained by removing the polymer in the nano-structure by baking. The structure which has it and its manufacturing method are provided.

  In the structure having a superhydrophobic surface of the present invention, a superhydrophobic nanostructure composite is formed on the surface of a solid substrate such as metal, glass, inorganic metal oxide, plastic, fiber, paper, etc. of any shape. The structure itself may be in any form such as a complex plane, curved surface, rod shape, tubular shape, etc., and is limited or comprehensive in any of the inside, outside the tube, inside the container, and outside the container. In particular, superhydrophobicity can be expressed. In addition, since the superhydrophobic nanostructure composite to be coated uses a polymer layer formed on the substrate by contact between the polymer solution having a polyethyleneimine skeleton and the solid substrate as a template, It is also easy to select and coat only a part. Further, since the superhydrophobic nanostructure composite on the surface of the solid substrate is basically silica, it can be developed into a coating material that is also resistant to solvents and corrosion. Furthermore, it is easy to incorporate various functional parts such as metal ions and metal nanoparticles into the composite. Therefore, it can be used for various devices that utilize various functions added to the superhydrophobicity. Specifically, super-hydrophobic coating, super-hydrophobic coloring material, super-hydrophobic antibacterial paint, catalyzed microreactor, enzyme immobilization device, substance separation and purification device, blood circulation device, microchannel, solution transport / transfer It can be applied to a wide range of industrial fields such as equipment, self-cleaning containers, printing nozzles, chips, sensors, and various micro battery construction.

  The present inventors have already used a crystalline aggregate in which a polymer having a linear polyethyleneimine skeleton grows in an aqueous medium in a self-organizing manner as a reaction field, and hydrolyzes alkoxysilane on the surface of the aggregate in a solution. Provided is a silica-containing nanostructure having a complicated shape having a nanofiber as a basic unit, which is obtained by decomposing condensation and precipitating silica (Japanese Patent Laid-Open No. 2005-264421, Japanese Patent Laid-Open No. 2005-336440, (See JP 2006-063097 A and JP 2007-051056 A.)

  The basic principle of this technique is to spontaneously grow a crystalline aggregate of a polymer containing a polyethyleneimine skeleton in a solution. Once a crystalline aggregate is formed, the dispersion of the crystalline aggregate is then simply used. A silica source is mixed therein, and the deposition of silica is allowed to occur naturally only on the surface of the crystalline aggregate (so-called sol-gel reaction). The silica-containing nanostructures obtained by this method basically have nanofibers as units for structure formation, and the spatial arrangement of these units induces the shape of the entire structure, so that nano-level gaps are not generated. Many have a large surface area. This is considered to be an efficient process that satisfies the rough surface structure formation at the nano level.

  If the growth of the crystalline aggregate of the polyethyleneimine skeleton-containing polymer in the solution proposed above proceeds on the surface of a solid substrate of any shape, and a layer of the crystalline aggregate of the polymer can be formed on the substrate It is considered that a nanostructure having a new surface in which silica and a polymer are combined on the solid substrate can be constructed. If this working model is further expanded, even if the layer formed on the solid substrate is not a crystalline aggregate of a polymer, but a stable layer consisting of an amorphous molecular aggregate of a polyethyleneimine skeleton-containing polymer, Similarly, it is thought that a new nano surface in which silica and a polymer are combined can be constructed.

  Therefore, the fundamental problem in solving the above problem is only how to form a stable layer (film) of the self-assembled aggregate of the polyethyleneimine skeleton-containing polymer on the surface of the solid substrate. An important feature of a polymer containing a polyethyleneimine skeleton is that it is basic and has a very high polarity. Accordingly, the polyethyleneimine skeleton-containing polymer is a metal substrate, a glass substrate, an inorganic metal oxide substrate, a plastic substrate having a polar surface, a cellulose substrate, a lot of electron acceptor substrates, and Lewis acidic substrates. It has a strong interaction force (adsorption force) with various surfaces such as acidic substrates, polar substrates and hydrogen bonding substrates. Taking advantage of this feature of the polyethyleneimine skeleton-containing polymer, the present inventors contacted (immersed) a molecular substrate solution of a solid substrate surface of an arbitrary shape and a polyethyleneimine skeleton-containing polymer having a constant concentration and a constant temperature to obtain a solution. It was found that the polymer therein was attracted to the surface of the solid substrate, and as a result, a layer composed of molecular aggregates of the polymer could be easily formed over the entire contacted portion of the surface of the solid substrate. Furthermore, the solid base material coated with the polymer layer thus obtained is immersed in a silica source solution, so that the solid base material is a nanostructure composed of a complex silica and polymer. A surface that exhibits superhydrophobicity on a solid substrate was constructed by chemically bonding silanes having hydrophobic groups to the silica portion of the nanostructure.

  In the present invention, the nanostructure means a structure having a certain shape composed of repeating units (units) on the order of nanometers. Specifically, the nanostructure (y1) is the polymer described above. The nanostructure (y2) is a structure composed of units containing silica as a main constituent. Superhydrophobic nanostructure composites (Z1) and (Z2) are obtained by hydrophobizing the nanostructures (y1) and (y2), respectively.

  The structure having a superhydrophobic surface of the present invention (hereinafter abbreviated as structure) contains a polymer (A) having a polyethyleneimine skeleton (a) on the surface of a solid substrate (X) and silica (B). The nanostructure material (y1) or the nanostructure material (y2) obtained by removing the polymer (A) in the nanostructure (y1) by firing is coated with a hydrophobic group on the silica portion of the structure surface. Are combined. Furthermore, the structure of this invention can also contain a metal ion and a metal nanoparticle in this nanostructure (y1). Therefore, the structure of the present invention is composed of a solid substrate, a polymer, silica, a hydrophobic group bonded to silica, metal ions, metal nanoparticles, and the like. As described later, the metal nanoparticles referred to here indicate that the metal fine particles are present in a size of the order of nanometers, and need not be perfectly spherical, but for convenience, the term “particle” Describe. The present invention will be described in detail below.

[Solid substrate]
The solid substrate (X) used in the present invention is not particularly limited as long as the polymer (A) having a polyethyleneimine skeleton (a) described later can be adsorbed. For example, glass, metal, metal oxide, etc. Inorganic material base material, organic material base material such as resin (plastic), cellulose, fiber, paper, etc. Furthermore, glass, metal, metal oxide surface, etched base material, surface of resin base material Treated and ozone treated substrates can be used.

  Although it does not specifically limit as an inorganic material type glass substrate, For example, glass, such as heat resistant glass (borosilicate glass), soda-lime glass, crystal glass, optical glass which does not contain lead and arsenic, is used suitably. Can do. In the use of a glass substrate, the surface can be used by etching with an alkaline solution such as sodium hydroxide, if necessary.

  Although it does not specifically limit as an inorganic material type metal base material, For example, the base material which consists of iron, copper, aluminum, stainless steel, zinc, silver, gold | metal | money, platinum, or these alloys etc. can be used suitably.

  Although it does not specifically limit as an inorganic material type metal oxide base material, For example, ITO (indium tin oxide), a tin oxide, copper oxide, a titanium oxide, a zinc oxide, an alumina etc. can be used suitably.

  As the resin base material, for example, processed products of various polymers such as polyethylene, polypropylene, polycarbonate, polyester, polystyrene, polymethacrylate, polyvinyl chloride, polyethylene alcohol, polyimide, polyamide, polyurethane, epoxy resin, and cellulose can be used. it can. In the use of various polymers, the surface may be treated with plasma or ozone, or treated with sulfuric acid or alkali, if necessary.

  The shape of the solid substrate (X) is not particularly limited, and may be a flat or curved plate or a film. In particular, a tubular tube, a spiral tube of a tubular tube, a microtube; a container having an arbitrary shape (for example, a spherical shape, a square shape, a triangular shape, a cylindrical shape); an arbitrary shape (for example, a cylindrical shape, (Rectangle, triangle, etc.) A rod or a solid substrate in a fiber state can also be suitably used.

  In the method for producing the structure of the present invention, which will be described later, when the polymer (A) is removed by the firing step, it is needless to say that a solid substrate that does not deteriorate at the firing temperature must be used.

[Polymer having Polyethyleneimine Skeleton (a) (A)]
In the present invention, it is essential to use a polymer (A) having a polyethyleneimine skeleton (a) for the polymer layer formed on the solid substrate (X). The polymer (A) having the polyethyleneimine skeleton (a) may be a linear, star-shaped or comb-shaped homopolymer, or a copolymer having other repeating units. In the case of a copolymer, the molar ratio of the polyethyleneimine skeleton (a) in the polymer (A) is preferably 20% or more from the viewpoint of forming a stable polymer layer. It is more preferable that it is a block copolymer having 10 or more repeating units.

  The polyethyleneimine skeleton (a) may be either linear or branched, but is more preferably a linear polyethyleneimine skeleton having a high ability to form a crystalline aggregate. Whether the polymer is a homopolymer or a copolymer, a stable polymer layer is formed on the substrate (X) when the molecular weight corresponding to the polyethyleneimine skeleton is in the range of 500 to 1,000,000. It is preferable because it can be formed. The polymer (A) having the polyethyleneimine skeleton (a) can be obtained from a commercially available product or a synthesis method already disclosed by the present inventors (see the above-mentioned patent document).

  As will be described later, the polymer (A) can be used by dissolving in various solutions. At this time, in addition to the polymer (A) having the polyethyleneimine skeleton (a), the polymer (A) is compatible with the polymer (A). It can be used by mixing with other polymers. Examples of the other polymer include polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, poly (N-isopropylacrylamide), polyhydroxyethyl acrylate, polymethyloxazoline, polyethyloxazoline, and polypropyleneimine. By using these other polymers, it is possible to easily adjust the thickness of the nanostructure on the surface of the resulting structure, and thus the thickness of the superhydrophobic nanostructure composite.

[Silica (B)]
The surface of the base material of the structure obtained by the present invention is a nanostructure (y1) containing polymer (A) and silica (B) as main constituents, or a nanostructure containing silica (B) as main constituents. The main feature is that it is coated with (y2). As a silica source required for forming silica (B), for example, alkoxysilanes, water glass, hexafluorosilicon ammonium and the like can be used.

  As the alkoxysilanes, tetramethoxysilane, oligomers of methoxysilane condensates, tetraethoxysilane, oligomers of ethoxysilane condensates can be suitably used. Further, alkyl-substituted alkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, iso-propyltrimethoxysilane, iso-propyltriethoxysilane, etc., 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycid Xylpropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptotriethoxysilane, 3,3 -Trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, p -Chloromethylphenyltrimethoxysilane, p-chloromethylphenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane and the like can be used alone or in combination.

  In addition, other silica metal compounds may be mixed with the silica source. For example, tetrabutoxytitanium, tetraisopropoxytitanium, or an aqueous solution of titanium bis (ammonium lactate) dihydroxide stable in an aqueous medium, an aqueous solution of titanium bis (lactate), a propanol / water mixture of titanium bis (lactate), titanium (ethyl) Acetoacetate) diisopropoxide, titanium sulfate, hexafluorotitanium ammonium and the like can be used.

[Metal ions]
The surface of the base material in the structure of the present invention is covered with the nanostructure described above. In this nanostructure (y1), metal ions can be stably incorporated, and thus a structure coated with a superhydrophobic nanostructure composite containing metal ions can be obtained.

  Since the polyethyleneimine skeleton (a) in the polymer (A) has a strong coordination ability with respect to metal ions, the metal ions coordinate with the ethyleneimine units in the skeleton to form a metal ion complex. The metal ion complex is obtained by coordination of a metal ion to an ethyleneimine unit. Unlike a process such as ionic bonding, the metal ion is coordinated to an ethyleneimine unit regardless of whether the metal ion is a cation or an anion. Can form a complex. Accordingly, the metal species of the metal ion is not limited as long as it can coordinate with the ethyleneimine unit in the polymer (A), and is not limited to alkali metal, alkaline earth metal, transition metal, metalloid, lanthanum metal, poly Any of metal compounds such as oxometalates may be used, and they may be used alone or in combination.

Examples of the alkali metal include Li, Na, K, Cs and the like, and examples of counter ions of the alkali metal ions include Cl, Br, I, NO ₃ , SO ₄ , PO ₄ , ClO ₄ , PF ₆ , Examples thereof include BF ₄ and F ₃ CSO ₃ .

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

As a transition metal-based metal ion, even if it is a transition metal cation (M ^{n +} ), an acid group anion (MO _x ⁿ⁻ ) composed of a bond with oxygen, or an anion composed of a halogen bond ( ML _x ⁿ⁻ ) can also be suitably used. 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 cations of various transition metals (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. Counteranion of these metal cations, Cl, NO 3, _SO 4 or polyoxometalate compound anion, or may be an organic anion of carboxylic _acids. However, for those that are easily reduced by the ethyleneimine skeleton, such as Ag, Au, and Pt, it is preferable to prepare an ionic complex by suppressing the reduction reaction, for example, by adjusting the pH to an acidic condition.

Examples of the transition metal anion include various 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. Anions and the like.

  As the metal ion in the present invention, a metal compound of polyoxometalates in which the transition metal anion is fixed in silica (B) through 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, anions (ML _x ⁿ⁻ ) containing various metals, such as AuCl ₄ , PtCl ₆ , RhCl ₄ , ReF ₆ , NiF ₆ , CuF ₆ , RuCl ₆ , In ₂ Cl _6, etc. The coordinated anion can also be suitably used for forming an ion complex.

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

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

[Metal nanoparticles]
As described above, in the present invention, metal ions can be incorporated into the nanostructures in the structure. Accordingly, among these metal ions, metal ions that are easily reduced by a reduction reaction can be converted into metal nanoparticles, whereby the metal nanoparticles can be contained in the structure (y1).

  Examples of the metal species of the metal nanoparticles include copper, silver, gold, platinum, palladium, manganese, nickel, rhodium, cobalt, ruthenium, rhenium, molybdenum, iron, and the like, and the metal in the nanostructure (y1) One kind or two or more kinds of nanoparticles may be used. Among these metal species, silver, gold, platinum, and palladium are particularly preferable because the metal ions are spontaneously reduced at room temperature or in a heated state after being coordinated to the ethyleneimine unit.

  The size of the metal nanoparticles in the nanostructure (y1) can be controlled in the range of 1 to 20 nm. Moreover, a metal nanoparticle can be fixed to the inside or the outer surface of the nanostructure (y1) of the polymer (A) and silica (B).

[Organic dye molecules]
In the present invention, the polyethyleneimine skeleton (a) in the nanostructure (y1) covering the structure is composed of a compound having an amino group, a hydroxy group, a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, a hydrogen bond and / or Alternatively, a physical coupling structure can be formed by electrostatic attraction. Therefore, organic dye molecules having these functional groups and the like can be contained in the nanostructure (y1).

  As the organic dye molecule, a monofunctional acidic compound or a bifunctional or higher polyfunctional acidic compound can be suitably used.

  Specifically, for example, aromatic acids such as tetraphenylporphyrin tetracarboxylic acid and pyrene dicarboxylic acid, naphthalene disulfonic acid, pyrene disulfonic acid, pyrene tetrasulfonic acid, anthraquinone disulfonic acid, tetraphenyl porphyrin tetrasulfonic acid, phthalocyanine tetra Aromatic or aliphatic sulfonic acids such as sulfonic acid and pipes (PIPES), acid yellow, acid blue, acid red, direct blue, direct yellow, direct red series azo dyes and the like can be mentioned. In addition, a dye having a xanthene skeleton, for example, rhodamine, erythrosine, and eosin dyes can be used.

[Nanostructure (y1) containing polymer (A) and silica (B)]
The nanostructure (y1) containing the polymer (A) and silica (B) is basically a composite nanofiber having a structure in which the polymer (A) is coated with silica (B). While changing the spatial arrangement on the surface, the entire state is formed, and various patterns or morphologies are formed. For example, a turf shape (nano turf) in which the nanofabric is mainly grown on the entire surface of the solid substrate with the long axis of the fiber facing the vertical direction (nano turf), or a rice field that is slightly tilted from the vertical direction (nano rice field), A tatami-like shape (nano-tatami mat) in which the nanofibers lie down on the entire surface of the base material, a sponge-like shape (nano-sponge) in which the nanofibers form a network on the entire surface of the base material, A wide variety of hierarchical structures can be configured.

  The thickness of the composite nanofiber of the basic unit in the higher order structure such as the nano turf shape, the nano rice field shape, the nano tatami shape, or the nano sponge shape is in the range of 10 to 200 nm. The length (major axis direction) of the nanofiber in the nano turf shape or the nano rice field shape can be controlled in the range of 50 nm to 2 μm.

  Although the thickness at the time of coating on the solid substrate is related to the spatial arrangement state of the nanofibers, it can be varied in a range of about 50 nm to 20 μm. Nano-turf shape is characterized by a strong tendency of nanofibers to stand upright, the length of the fibers basically constituting the thickness, and the length of each fiber is fairly uniform. In the nano rice field, the nanofibers tend to extend obliquely and the film thickness is smaller than the fiber length. In addition, the thickness of the nano rice field-like layer is characterized by being determined by the overlaid state of the nanofibers. The thickness of the nanosponge-like layer is characterized in that it is determined by the degree to which the nanofibers are swelled by complex entanglements having regularity. When a network is formed, the thickness is determined depending on the overlapping state.

  In the nanostructure (y1), the component of the polymer (A) can be adjusted at 5 to 30% by mass. The spatial arrangement structure (higher order structure) can be changed by changing the content of the polymer (A) component.

  In addition, when a metal ion, metal nanoparticle, organic dye molecule, or the like is contained in the nanostructure (y1), the higher-order structure can be controlled depending on the type. Even in this case, the basic unit is a nanofiber as described above, and these combine to form a complex shape.

  The amount of metal ions taken up when taking in metal ions is preferably adjusted in the range of 1/4 to 1/200 equivalent to 1 equivalent of ethyleneimine unit in polymer (A), and this ratio is changed. By this, the thickness of the coating layer made of the nanostructure can be changed. In addition, the coating layer at this time may develop color depending on the metal species.

  The amount of metal nanoparticles incorporated when incorporating metal nanoparticles is preferably prepared in the range of 1/4 to 1/200 equivalent per 1 equivalent of ethyleneimine unit in the polymer (A). By changing the thickness, the thickness of the coating layer made of the nanostructure can be changed. In addition, the coating layer at this time may develop color depending on the metal species.

  The organic dye molecule incorporation amount when incorporating the organic dye molecule is preferably prepared in the range of 1/2 to 1/200 equivalent per 1 equivalent of the ethyleneimine unit in the polymer (A). By changing the thickness, the thickness and shape pattern of the coating layer made of the nanostructure can be changed.

  Moreover, 2 or more types, such as a metal ion, a metal nanoparticle, and an organic pigment | dye molecule | numerator, can also be simultaneously taken in into a nanostructure (y1).

[Nanostructure (y2) containing silica (B) as main component]
Silica (B) from which polymer (A) was removed by firing together with solid substrate (X) nanostructure (y1) containing polymer (A) and silica (B) obtained above It is possible to obtain a solid substrate (X) coated with a nanostructure (y2) having as a main component. At this time, although the polymer (A) disappears by firing, the silica (B) maintains its structure. Accordingly, the shape of the nanostructure (y2) is also determined by the spatial arrangement of the nanostructure (y1). That is, for example, the nanofabric is a turf shape (nano turf) in which the long axis of the fiber grows mainly on the entire surface of the solid substrate or is slightly tilted from the vertical direction (nano rice field) ), Tatami shape (nano tatami mat) in which nanofibers lie down on the entire surface of the substrate, and sponge shape (nano sponge) in which nanofibers form a network on the entire surface of the substrate. Make up structure.

[Hydrophobic treatment]
In the present invention, the surface of the nanostructure (y1) or nanostructure (y2) must be modified with a hydrophobic group in order to obtain a superhydrophobic surface. The modification can be easily performed by contact with a compound having a hydrophobic group.

  Examples of the hydrophobic group include an alkyl group having 1 to 22 carbon atoms and an aromatic group which may have a substituent (as the substituent, an alkyl group having 1 to 22 carbon atoms, a fluorinated alkyl group, Hydrophobic groups such as partially fluorinated alkyl groups), fluorinated alkyl groups having 1 to 22 carbon atoms, and partially fluorinated alkyl groups having 1 to 22 carbon atoms.

  In order to efficiently modify these hydrophobic groups to the silica (B) of the nanostructure (y1) or nanostructure (y2), a silane coupling agent having the hydrophobic group is used alone or in combination. And preferably used.

  Examples of the silane coupling agent include methyltrimethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, iso-propyltrimethoxysilane, iso Examples thereof include alkyltrimethoxysilanes or alkyltrichlorosilanes having an alkyl group having 1 to 22 carbon atoms such as propyltriethoxysilane, pentyltrimethoxysilane, and hexyltrimethoxysilane.

  Further, as having a fluorine atom effective for lowering the surface tension, a (partially) silane coupling agent having a fluorinated alkyl group, such as 3,3,3-trifluoropropyltrimethoxysilane, tridecafluoro-1, 1,2,2-tetrahydrooctyl) trichlorosilane and the like can also be used.

  Moreover, as a silane coupling agent having an aromatic group, phenyltrimethoxysilane, phenyltriethoxysilane, p-chloromethylphenyltrimethoxysilane, p-chloromethylphenyltriethoxysilane, and the like can be taken up.

[Method for producing structure having superhydrophobic surface]
The manufacturing method of the structure of the present invention basically includes
Solution of polymer (A) having polyethyleneimine skeleton (a), mixed solution of polymer (A) having polyethyleneimine skeleton (a) and metal ion, polymer (A) having polyethyleneimine skeleton (a) and organic dye After contacting the mixed solution of molecules and the like with the surface of the solid substrate (X), the substrate (X) is taken out, and the polymer (A) having a polyethyleneimine skeleton (a) on the surface of the substrate (X) And a step (1) of obtaining a base material on which a polymer layer comprising metal ions or organic dye molecules used in combination is formed,
Due to the catalytic function of the polyethyleneimine skeleton (a) in the polymer layer adsorbed on the substrate surface by contacting the substrate formed by the polymer layer with the silica source liquid (B ′), the silica (B) Depositing on top to form a nanostructure (y1) and coating the substrate with it (2);
Step (3) of introducing a hydrophobic group to the surface of the nanostructure by bringing the nanostructure (y1) obtained in the step (2) into contact with a solution containing a silane coupling agent having a hydrophobic group.
Consists of Through these steps, a structure having a superhydrophobic surface in which polyethyleneimine is included in the surface composition can be produced.

  Moreover, in the manufacturing method of the structure of the present invention, the solid substrate (X) coated with the nanostructure (y1) obtained through the above steps (1) and (2) is heated and fired to thereby form the nanostructure. Producing a structure having a superhydrophobic surface in which polyethyleneimine is not included in the surface composition by providing a step of baking and removing the polymer (A) having a polyethyleneimine skeleton (a) in the body (y1) Can do.

  As the polymer (A) having the polyethyleneimine skeleton (a) used in the step (1), the aforementioned polymer can be used. In addition, the solvent that can be used for obtaining the solution of the polymer (A) is not particularly limited as long as the polymer (A) can be dissolved, and examples thereof include water, organic solvents such as methanol and ethanol, These mixed solvents can be used as appropriate.

  The concentration of the polymer (A) in the solution is not particularly limited as long as the polymer layer can be formed on the solid substrate (X), but the desired pattern formation and the density of the polymer adsorbed on the substrate surface are increased. In this case, the range is preferably 0.5% by mass to 50% by mass, and more preferably 5% by mass to 50% by mass.

  In the solution of the polymer (A) having a polyethyleneimine skeleton (a), the above-mentioned other polymers that are soluble in the solvent and compatible with the polymer (A) can be mixed. The mixing amount of the other polymer may be higher or lower than the concentration of the polymer (A) having the polyethyleneimine skeleton (a).

  When forming the coating layer which consists of nanostructure (y1) containing a metal ion, the said metal ion is mixed in the solution of the polymer (A) which has a polyethyleneimine frame | skeleton (a). The concentration of the metal ion is preferably adjusted to ¼ equivalent or less of the ethyleneimine unit in the polyethyleneimine skeleton (a).

  Moreover, when forming the coating layer which consists of nanostructure (y1) containing an organic pigment molecule etc., the said organic pigment molecule etc. are mixed in the solution of the polymer (A) which has a polyethyleneimine skeleton (a). . It is preferable to adjust the concentration of the organic dye molecule or the like to ½ equivalent or less of the ethyleneimine unit in the polyethyleneimine skeleton (a).

  Moreover, in order to produce a polymer layer in a process (1), a solid base material (X) is made to contact with the solution of a polymer (A). As the contact method, it is preferable to immerse the desired solid substrate (X) in the solution of the polymer (A).

  In the dipping method, the substrate and the solution can be brought into contact with each other in such a manner that the substrate (non-container shape) is placed in the solution or the solution is placed in the substrate (container shape) depending on the state of the substrate. During the immersion, the temperature of the polymer (A) solution is preferably in a heated state, and a temperature of about 50 to 90 ° C. is suitable. The time for bringing the solid substrate (X) into contact with the solution of the polymer (A) is not particularly limited, and is preferably selected within a few seconds to 1 hour according to the material of the substrate (X). When the material of the base material has a strong binding ability with polyethyleneimine, for example, it may be several seconds to several minutes for glass, metal, etc. good.

  After contacting the solid substrate (X) with the polymer (A) solution, the substrate is taken out of the polymer (A) solution and allowed to stand at room temperature (around 25 ° C.). A body layer is formed on the surface of the substrate (X). Alternatively, the substrate (X) is taken out from the solution of the polymer (A), and then immediately put into distilled water at 4 to 30 ° C. or an aqueous ammonia solution at a room temperature to a freezing temperature, whereby the spontaneous polymer (A) An aggregate layer may be formed.

  As a method of contacting the surface of the solid substrate (X) with the solution of the polymer (A), for example, a method such as printing or printing with a jet printer can be used in addition to coating with a spin coater, bar coater, applicator or the like. In particular, when the contact is made in a fine pattern, a method using a jet printer is suitable.

  In the step (2), the polymer layer formed via the step (1) is brought into contact with the silica source liquid (B ′) to deposit silica (B) on the surface of the polymer layer, and the polymer (A) and silica (B ) And a nanostructure (y1). Even when the polymer layer contains metal ions, organic dye molecules, or the like, the target nanostructure (y1) can be formed by precipitating silica (B) by the same method.

  As the silica source liquid (B ′) used at this time, the above-mentioned various silica source aqueous solutions, alcohol solvents, for example, aqueous organic solvent solutions such as methanol, ethanol and propanol, or mixed solvents of these with water A solution can be used. Moreover, the water glass aqueous solution which adjusted the pH value to the range of 9-11 can also be used. The silica source liquid (B ′) to be used can be mixed with a metal alkoxide other than silica.

  Moreover, the alkoxysilane compound as a silica source can be used even in a solvent-free bulk liquid.

  As a method for bringing the solid substrate formed with the polymer layer into contact with the silica source liquid (B ′), an immersion method can be preferably used. It is sufficient that the immersion time is 5 to 60 minutes, but the time can be further increased as necessary. The temperature of the silica source liquid (B ′) may be room temperature or a heated state. In the case of heating, it is desirable to set the temperature to 70 ° C. or lower in order to regularly deposit silica (B) on the surface of the solid substrate (X).

  By selecting the type and concentration of the silica source, the structure of the nanostructure (y1) of the precipitated silica (B) and the polymer (A) can be adjusted. It is preferable to select the concentration appropriately.

  Polyethyleneimine can reduce noble metal ions such as gold, platinum, silver, palladium and the like to metal nanoparticles. Accordingly, the structure obtained by the above-described process and covered with the nanostructure (y1) is contacted with the aqueous solution of the noble metal ion, whereby the noble metal ion is converted into a metal in the nanostructure (y1). The nanostructure which can be converted into a nanoparticle and has a metal nanoparticle can be obtained.

  A dipping method can be preferably used as the method of contacting with an aqueous solution of noble metal ions. As the aqueous solution of noble metal ions, aqueous solutions of chloroauric acid, sodium chloroaurate, chloroplatinic acid, sodium chloroplatinate, silver nitrate and the like can be suitably used, and the aqueous solution concentration of noble metal ions is 0.1 to 5 mol. % Is preferred.

  The temperature of the aqueous solution of noble metal ions is not particularly limited, and may be in the range of room temperature to 90 ° C. However, in order to promote the reduction reaction, it is preferable to use a heated aqueous solution of 50 to 90 ° C. Moreover, the time for immersing the structure in the aqueous solution of metal ions may be 0.5 to 3 hours, and about 30 minutes is sufficient when immersed in the heated aqueous solution.

  In the case of a metal ion that is difficult to reduce with polyethyleneimine alone, a step of bringing the metal ion in the structure having the metal ion obtained above into contact with a reducing agent, particularly a low molecular weight reducing agent solution or hydrogen gas, In combination, by reducing the metal ions, a nanostructure containing the metal nanoparticles can be obtained.

  Examples of the reducing agent that can be used at this time include ascorbic acid, aldehyde, hydrazine, sodium borohydride, ammonium borohydride, hydrogen, and the like. When reducing metal ions using a reducing agent, the reaction can be carried out in an aqueous medium. The structure containing the metal ions is immersed in the reducing agent solution or left in a hydrogen gas atmosphere. Can be used. At this time, the temperature of the reducing agent aqueous solution may be in the range of room temperature to 90 ° C., and the concentration of the reducing agent is preferably 1 to 5 mol%.

  The metal species of the metal ion that can be applied here are not particularly limited, but copper, manganese, chromium, nickel, tin, vanadium, and palladium are preferable because the reduction reaction proceeds promptly.

  When the polymer (B) in the nanostructure (y1) is removed by heating and baking to obtain the nanostructure (y2), the baking temperature can be set to 300 to 600 ° C. When this step is performed, the solid substrate (X) is selected from heat-resistant inorganic materials such as glass, metal oxide, and metal.

  The heating and firing time is desirably in the range of 1 to 7 hours, but it may be fired for a short time when the temperature is high, and it is preferable to appropriately adjust the time such as increasing the time when the temperature is low.

  Through the step of bringing the solid substrate (X) coated with the nanostructure (y1) or nanostructure (y2) obtained above into contact with the silane coupling agent having a hydrophobic group described above, the surface To superhydrophobic.

  At this time, the silane coupling agent having a hydrophobic group can be used by dissolving in a solvent such as chloroform, methylene chloride, cyclohexanone, xylene, toluene, ethanol, methanol and the like. These solvents can be used alone or in combination, and the concentration of the silane coupling agent is preferably adjusted to 1 to 5 wt%.

  Furthermore, it is desirable to use the above solution by mixing it with an ethanol solution of 1-5 wt% ammonia water. As a volume ratio at the time of mixing, it is suitable to make the ammonia water ethanol solution into the range of 5-10 equivalent with respect to 1 equivalent of a silane coupling agent solution.

  The contact with the silane coupling agent is preferably by a method of immersing in the mixed solution obtained above, and the alkylsilane of the silane coupling agent is silica in the nanostructure (y1) or nanostructure (y2). (B) It can be converted into a structure having a final superhydrophobic nanosurface introduced by Si—O—Si bond in the part.

  The immersion time in the solution is preferably in the range of 1 hour to 3 days, and is suitably selected depending on the concentration of the silane coupling agent and the concentration of ammonia in the solution. The contact angle can be gradually increased as the immersion time is increased in the solution having a constant concentration, and the contact angle becomes close to the maximum value of 180 ° after the fixed time. When this number appears, the introduction of hydrophobic residues on the surface can be considered saturated. Depending on the desired level of hydrophobicity, the immersion time can be selected.

  Hereinafter, the present invention will be described in more detail with reference to examples. Unless otherwise specified, “%” represents “mass%”.

[Shape analysis of nanostructures by scanning electron microscope]
The isolated and dried nanostructure was fixed to a sample support with a double-sided tape, and observed with a surface observation device VE-9800 manufactured by Keyence.

[Contact angle measurement]
The contact angle was measured with an automatic contact angle meter Contact Angle System OCA (manufactured by Dataphysics).

Synthesis example 1
<Synthesis of linear polyethyleneimine (L-PEI)>
3 g of commercially available polyethyloxazoline (number average molecular weight 50,000, average polymerization degree 5,000, manufactured by Aldrich) was dissolved in 15 mL of 5 mol / L 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 three times with methanol to obtain a white polyethyleneimine powder. When the obtained powder was identified by ¹ H-NMR (heavy water, manufactured by JEOL Ltd., AL300, 300 MHz), the peak derived from the side chain ethyl group of polyethyloxazoline was 1.2 ppm (CH ₃ ) and 2. It was confirmed that 3 ppm (CH ₂ ) disappeared completely. 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 in a desiccator at room temperature 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 5,000 before hydrolysis.

Synthesis example 2
<Synthesis of star-shaped polyethyleneimine (B-PEI) centered on benzene ring>
Jin, J .; Mater. Chem. , 13, 672-675 (2003), a star-shaped polymethyloxazoline in which six polymethyloxazoline arms were bonded to the center of the benzene ring as a precursor polymer was synthesized as follows.

Put 0.021 g (0.033 mmol) of hexakis (bromomethyl) benzene as a polymerization initiator in a test tube set with a magnetic stirrer, attach a three-way cock to the test tube, and then put it in a vacuum state. Was replaced with nitrogen. Under a nitrogen stream, 2.0 ml (24 mmol) of 2-methyl-2-oxazoline and 4.0 ml of N, N-dimethylacetamide were sequentially added from the inlet of the three-way cock using a syringe. When the test tube was heated to 60 ° C. on an oil bath and kept for 30 minutes, the mixture became transparent. The transparent mixture was further heated to 100 ° C. and stirred at that temperature for 20 hours to obtain a precursor polymer. From this mixture the ¹ H-NMR measurement of the liquid, the conversion of monomer is 98 mol%, the yield was 1.8 g. When the average degree of polymerization of the polymer was estimated based on this conversion, the average degree of polymerization of each arm was 115. Moreover, in the molecular weight measurement by GPC, the mass average molecular weight of the polymer was 22,700, and the molecular weight distribution was 1.6.

Using this precursor polymer, polymethyloxazoline was hydrolyzed in the same manner as in Synthesis Example 1 to obtain star-shaped polyethyleneimine B-PEI in which 6 polyethyleneimines were bonded to the benzene ring core. ^{As a result of 1} H-NMR (TMS external standard, heavy water) measurement, it was confirmed that the peak of 1.98 ppm derived from the side chain methyl of the precursor polymer before hydrolysis completely disappeared.

  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 crystal powder was filtered, and the crystal powder was washed three times with cold water. The washed crystal powder was dried in a desiccator at room temperature (25 ° C.) to obtain star-shaped polyethyleneimine (B-PEI) in which six polyethyleneimines were bonded to the benzene ring core. The yield was 1.3 g (including crystal water).

Example 1
[Glass plate structure having superhydrophobic surface]
A 3 × 2 cm soda lime glass plate was immersed in the 4% aqueous solution of L-PEI obtained above (80 ° C. solution) and allowed to stand for 30 seconds. The plate was taken out and allowed to stand at room temperature for 5 minutes, and then immersed in a mixed solution of silica source (MS51 ^* / distilled water / IPA = 0.5 / 3/3 volume ratio) at room temperature for 20 minutes. The plate was taken out from the liquid, the surface was washed with ethanol, and dried at room temperature. When the surface of the obtained plate was observed by SEM, it was confirmed that the entire plate surface was covered with nano turf having nanofibers as a basic unit (FIG. 1).

On the other hand, 3 mL of 20% decyltrimethoxysilane (DTMS) chloroform solution was taken out, mixed with 30 mL ethanol, and then 0.6 mL ammonia water (concentration 28%) was added to the solution to prepare a mixed solution. did. The glass plate prepared above was immersed in the mixed solution, taken out after a certain time at room temperature, the surface was washed with ethanol, and dried while flowing nitrogen gas. The water contact angle of the structure thus obtained was measured. FIG. 2 shows changes in the contact angle depending on the immersion time of the hydrophobization treatment. The illustration in FIG. 2 is a water droplet contact angle photograph in each time zone.
^* MS51: Tetramethoxysilane tetramer (manufactured by Colcoat).

Example 2
[Glass plate structure having superhydrophobic surface]
The glass plate shown in FIG. 1 obtained by the route of Example 1 was baked at 500 ° C. for 2 hours to remove the internal polymer (FIG. 3), and then the decyltrimethoxysilane ( (DTMS) After being immersed in the solution for a certain time, the contact angle in each time zone was measured. FIG. 4 shows the results. Compared with the result in Example 1, it was suggested that the superhydrophobization after the removal of the polymer of polyethyleneimine skeleton in the nano turf in Example 2 proceeds more easily.

Example 3
[Glass plate structure with superhydrophobic surface showing long-term superhydrophobicity in water]
The structure obtained after being immersed for 3 hours in the hydrophobizing treatment step shown in the method of Example 2 was taken out after being immersed for a certain time in tap water, and the contact angle was measured. Table 1 shows the contact angles after immersion in tap water. The contact angle did not change even after one month and remained superhydrophobic. This strongly suggests that the structure has the property of repelling water for a long time even in water. That is, the structure has semi-permanent superhydrophobicity.

Example 4
[Polystyrene plate structure having superhydrophobic surface]
A 2 × 2 cm polystyrene plate was immersed in a concentrated sulfuric acid solution for 3 hours, and then the surface was washed with water and methanol and dried at room temperature for 5 minutes. Thereafter, the polystyrene plate was immersed in a 4% aqueous solution of B-PEI (80 ° C.) and allowed to stand for 30 seconds. The plate was taken out and allowed to stand at room temperature for 5 minutes, then applied to a silica source mixture (MS51 / water / IPA = 0.5 / 3/3 volume ratio) and then allowed to stand at room temperature for 20 minutes. The plate was taken out from the liquid, the surface was washed with ethanol, and dried at room temperature. The surface of the obtained plate was observed with SEM. FIG. 5 is a structural photograph of nanofibers coated on the plate surface. It was confirmed that the entire surface of the plate was covered with nanograss with nanofibers as the basic unit.

  On the other hand, 3 mL of 20% decyltrimethoxysilane (DTMS) chloroform solution was taken out, mixed with 30 mL ethanol, and then 0.6 mL ammonia water (concentration 28%) was added to the solution to prepare a mixed solution. did. The polystyrene plate prepared above was immersed in the mixed solution after 24 hours at room temperature. The plate was taken out, the surface was washed with ethanol, and dried while flowing nitrogen gas. The resulting structure had a water contact angle of 176 °.

Example 5
[Copper plate structure with superhydrophobic surface]
A 1 × 1 cm size copper plate was dipped in a 4% aqueous solution of L-PEI (80 ° C. solution) and allowed to stand for 30 seconds. The plate was taken out and allowed to stand at room temperature for 5 minutes, after being put on a mixed solution of silica source (MS51 / water / IPA = 0.5 / 3/3), and then allowed to stand at room temperature for 20 minutes. The plate was taken out from the liquid, the surface was washed with ethanol, and dried at room temperature. The surface of the obtained plate was observed with SEM (FIG. 6). It was confirmed that the copper plate surface was covered with a nanostructure having nanofibers as a basic unit. This was hydrophobized for 24 hours in the same manner as shown in Example 4. The water contact angle of the obtained structure was 178 °.

Example 6
[Structure containing gold nanoparticles in superhydrophobic surface]
The nanoturf-coated glass plate obtained in Example 1 was immersed in 2 mL of an aqueous solution (1%) of NaAuCl ₄ .2H ₂ O and heated at 80 ° C. for 1 hour. The glass tube was taken out, washed with distilled water and ethanol in this order, and then dried at room temperature. A thin wine red color appeared on the glass plate thus obtained. This wine red color is derived from plasmon absorption indicating the presence of gold nanoparticles in the nano turf covering the inner wall of the glass plate. Plasmon absorption derived from gold nanoparticles having a peak top of 520 nm was also observed from a reflection spectrum (manufactured by Hitachi, Ltd., UV-3500). From TEM observation of the nanofiber scraped off, gold nanoparticles having a size of 2 to 3 nm were confirmed. The glass plate containing the gold nanoparticles was hydrophobized for 24 hours in the same manner as shown in Example 4. The water contact angle of the obtained structure was 179 °.

Example 7
[Tubular structure with inner surface of glass tube made of superhydrophobic surface]
Polymer L-PEI obtained in Synthesis Example 1 was added to distilled water and heated to 90 ° C. to prepare a 4% aqueous solution. After connecting a glass pipette made of soda lime (inner diameter 6 mm, length 5 cm) and a syringe with a rubber tube, and sucking the heated polymer aqueous solution up to a certain standard in the glass tube, it was allowed to stand for 30 seconds. The polymer aqueous solution was discharged by a pushing force of a syringe. By this operation, an L-PEI polymer layer was formed on the inner wall of the glass tube. The glass tube was allowed to stand at room temperature for 5 minutes, and then the glass tube was immersed in 20 mL of a silica source solution of MS51 / water (volume ratio 1/1) for 30 minutes. After the glass tube was taken out and the inner wall of the glass tube was washed with ethanol, it was dried at room temperature. After this operation, a light blue reflected color was seen on the glass tube.

  The glass tube end obtained through the above process was slightly crushed, and the fragments were observed with SEM. FIG. 7 shows the result of the SEM photograph of the inner surface of the glass tube. On the inner wall, a dense array film having nanofibers as a unit structure was formed. The glass pipette obtained by the above method was added to a mixed solution prepared with 3 mL of 20% strength decyltrimethoxysilane (DTMS) chloroform solution, 30 mL ethanol, 0.6 mL aqueous ammonia (concentration 28%) at room temperature for 24 hours. Soaked. The pipette was taken out, the surface was washed with ethanol, and dried while flowing nitrogen gas. The pipette thus obtained was fixed at an inclination of 27 °, and when a water droplet was dropped therein, the water droplet flowed out of the pipe instantly. When the flow of water droplets was observed with an ultra-high speed camera (FIG. 8), the water droplets flowed in a round shape in a circular shape. This strongly suggests that the inner wall of the tube is superhydrophobic.

  For comparison, water drops were similarly dropped on an untreated glass pipette, but water did not flow through the tube in an attached state. FIG. 9 is a digital camera photograph in the attached state.

  Furthermore, a 10% sodium chloride aqueous solution migration test was performed using a pipette exhibiting superhydrophobicity. Each time a solution having a constant weight was sucked, the solution was transferred to another glass tube, and the change in the liquid weight accompanying the solution movement was examined. Even when the solution was repeatedly transferred 20 times, there was no change in the weight of the transferred solution. That is, when a pipette having a superhydrophobic inner wall was used, the sucked solution could be completely transferred without any loss such as adhesion in the pipette.

  As a comparison, when a similar test was performed with an ordinary pipette, it was found that droplets always adhered and remained on the inner wall of the pipette after moving the solution, which corresponded to 2% of the sucked solution.

  As a result, it was found that a pipette having a superhydrophobic surface can accurately move the solution by aqueous solution transportation.

Example 8
[Structure in which the surface of the dwarf yarn is a superhydrophobic surface]
50 mg of the kite string was immersed in an aqueous solution of 2% L-PEI (80 ° C. solution) and allowed to stand for 30 seconds. The yarn was taken out and allowed to stand at room temperature for 60 minutes, and then immersed in a mixed solution of silica source (MS51 / water / IPA = 0.5 / 3/3) at room temperature for 20 minutes. The yarn was taken out from the liquid, subjected to surface washing with ethanol and drying at room temperature to obtain a yarn structure whose surface was coated with silica. The surface of the obtained yarn was observed with SEM (FIG. 10). From the surface comparison before and after the silica coating, it was confirmed that the surface of the yarn was covered with a nanostructure having a nanofiber as a basic unit. This was hydrophobized for 24 hours in the same manner as shown in Example 4.

  The structure thus obtained was immersed in water for 10 minutes and then taken out and weighed before and after immersion. Before immersion, 12 mg of the structure remained at 12 mg even after immersion, and there was no water wetting such as residual water droplets on the surface. For comparison, when 15 mg of untreated silk thread was dipped in water and taken out, the weight was 8 times or more in a completely wet state. This suggests that yarns with superhydrophobic surfaces can completely repel water.

Example 9
[Structure in which the filter paper surface is a superhydrophobic surface]
A filter paper having a size of 2 × 2 cm was immersed in a 2% aqueous solution of L-PEI (80 ° C. solution) and allowed to stand for 30 seconds. The filter paper was taken out, allowed to stand at room temperature for 60 minutes, and then immersed in a mixed liquid of silica source (MS51 / water / IPA = 0.5 / 3/3) at room temperature for 20 minutes. The filter paper was taken out from the liquid, subjected to surface washing with ethanol and room temperature drying, to obtain a filter paper structure whose surface was coated with silica. The surface of the obtained filter paper was observed with SEM (FIG. 11). From the surface comparison before and after the silica coating, it was confirmed that the surface of the filter paper was covered with a nanostructure having nanofibers as a basic unit. This was hydrophobized for 24 hours in the same manner as shown in Example 4.

  The plane of the filter paper obtained in this way was spread at an angle of 3 ° and a water droplet was dropped on it, and the water droplet rolled like a polka dot and bounced off the surface of the filter paper. The water did not wet the filter paper.

2 is a scanning electron micrograph obtained in Example 1 before hydrophobization treatment. The glass surface is coated with “nano turf” which is a nanostructure made of polyethyleneimine and silica. The contact angle change by hydrophobizing the “nano turf” obtained in Example 1. The illustration is a photograph of a change in the contact angle of water droplets at each processing time. In the graph, the contact angle was improved by extending the hydrophobic treatment time. 2 is a scanning electron micrograph obtained in Example 2 before hydrophobization treatment. The glass surface was composed of “nano turf” made of silica from which polyethyleneimine had been removed. The contact angle change by hydrophobizing the “nano turf” obtained in Example 2. The illustration is a photograph of a change in the contact angle of water droplets at each processing time. In the graph, the contact angle was improved by extending the hydrophobic treatment time. 2 is a scanning electron micrograph of a pre-hydrophobic treated polystyrene plate obtained in Example 4. FIG. 6 is a scanning electron micrograph of a copper plate before hydrophobization treatment obtained in Example 5. FIG. 6 is a scanning electron micrograph of the inner wall of the glass pipette before hydrophobic treatment obtained in Example 7. FIG. Left is a low-magnification photograph; right is a high-magnification photograph. It is a high-speed camera photograph that a water droplet rolls in a spherical state inside a pipette tube having a hydrophobic inner wall obtained in Example 7. The photograph of the comparative example in Example 7. FIG. Inside a normal glass pipette, water adheres to the wall. 10 is a scanning electron micrograph of the kite string in Example 8. a: Thread surface photograph. b: Surface photograph of the silk-coated post-silk yarn before hydrophobization treatment c: High magnification photograph of b. 4 is a scanning electron micrograph of a filter paper structure coated with a nanostructure before hydrophobic treatment obtained in Example 9. FIG. The left is a low-magnification photograph and the right is a high-magnification photograph.

Claims (11)

A solid substrate (X) having a surface coated with a superhydrophobic nanostructure composite (Z1),
The superhydrophobic nanostructure composite (Z1) has a hydrophobic group in the silica (B) in the nanostructure (y1) containing the polymer (A) having a polyethyleneimine skeleton (a) and silica (B). A structure having a superhydrophobic surface, wherein the structure is a complex formed by bonding. The nanostructure (y1) has a nanofiber having a thickness in a range of 10 to 200 nm and a length in a range of 50 nm to 2 μm as a basic unit, and the long axis of the nanofiber is a solid substrate (X) The structure according to claim 1, wherein the structure is oriented in a direction substantially perpendicular to the surface of the substrate. The nanostructure (y1) has a nanofiber having a thickness in a range of 10 to 200 nm as a basic unit, and the nanofiber forms a net-like structure on a solid substrate (X). 1. The structure according to 1. The structure according to any one of claims 1 to 3, wherein the nanostructure (y1) contains metal ions or metal nanoparticles. A step of immersing the solid substrate (X) in a solution containing the polymer (A) having a polyethyleneimine skeleton (a) and then taking it out to form a polymer layer on the surface of the solid substrate (X) ( 1- 1 ) and
The solid substrate (X) having the polymer layer obtained in the step (1-1) is brought into contact with the silica source liquid (B ′), and silica (in the polymer layer on the surface of the solid substrate (X)) B) precipitating, and step of forming nanostructures (y1) (1- 2),
The surface of the step (1 2) obtained in nanostructures on a solid substrate (y1), and treating with a silane coupling agent having a hydrophobic group (1-3),
A method for producing a structure coated with a superhydrophobic nanostructure composite, comprising: A step of immersing the solid substrate (X) in a solution containing the polymer (A) having a polyethyleneimine skeleton (a) and then taking it out to form a polymer layer on the surface of the solid substrate (X) ( 2- 1) and
The solid substrate (X) having the polymer layer obtained in the step (2-1) is brought into contact with the silica source liquid (B ′), and silica (in the polymer layer on the surface of the solid substrate (X)) B) precipitating, and step of forming nanostructures (y1) (2- 2),
The solid substrate (X) coated with the nanostructure (y1) obtained in the step (2-2) is further immersed in an aqueous ionic solution of a noble metal selected from the group consisting of gold, silver and platinum. Step of allowing the noble metal ion to penetrate into the nanostructure (y1) and forming a metal nanoparticle of the noble metal by a spontaneous reduction action by the polyethyleneimine skeleton (a) in the nanostructure (y1) ( 2 - 3) and,
The step (2-3) obtained in the solid substrate (X) on the nanostructure surface of (y1), the step (2-4) is treated with a silane coupling agent having a hydrophobic group,
A method for producing a structure coated with a superhydrophobic nanostructure composite containing metal nanoparticles, comprising: The solid substrate (X) is immersed in a solution containing the polymer (A) having a polyethyleneimine skeleton (a) and metal ions, and then taken out. The solid substrate (X) contains metal ions on the surface thereof. A step ( 3-1 ) of forming a polymer layer;
The solid substrate (X) having the polymer layer obtained in the step (3-1) is brought into contact with the silica source liquid (B ′), and silica (in the polymer layer on the surface of the solid substrate (X)) B) precipitating, as in step (3-2) to form nanostructures (y1) containing a metal ion,
The surface of the step (3-2) obtained in the solid substrate (X) on the nanostructure (y1), and treating with a silane coupling agent having a hydrophobic group (3-3),
A method for producing a structure coated with a superhydrophobic nanostructure composite containing metal ions, comprising: A step of immersing the solid substrate (X) in a solution containing the polymer (A) having a polyethyleneimine skeleton (a) and then taking it out to form a polymer layer on the surface of the solid substrate (X) ( 4- 1) and
The solid substrate (X) having the polymer layer obtained in the step (4-1) is brought into contact with the silica source liquid (B ′), and silica (in the polymer layer on the surface of the solid substrate (X)) B) precipitating, and step of forming nanostructures (y1) (4- 2),
The (4-2) in the nanostructure (y1) coated with the solid substrate (X) is then fired to obtain, nanostructures polymer having (A) (y1) polyethyleneimine skeleton (a) in removed by the step of the nanostructure (y2) and (4-3),
The surface of the step (4-3) obtained in nanostructures on a solid substrate (y2), and treating with a silane coupling agent having a hydrophobic group (4 4),
A method for producing a structure coated with a superhydrophobic nanostructure composite, comprising: The structure obtained by coating the surface of the solid substrate (X) obtained by the production method according to claim 8 with a superhydrophobic nanostructure composite (Z2),
The superhydrophobic nanostructure composite (Z2) is a composite formed by bonding a hydrophobic group to the silica (B) in the nanostructure (y2) containing silica (B) as a main constituent. A structure having a characteristic superhydrophobic surface. The nanostructure (y2) has a nanofiber having a thickness in the range of 10 to 200 nm and a length in the range of 50 nm to 2 μm as a basic unit, and the long axis of the nanofiber is a solid substrate (X) The structure according to claim 9 , wherein the structure faces in a direction substantially perpendicular to the surface of the surface. The nanostructure (y2) has a nanofiber having a thickness in a range of 10 to 200 nm as a basic unit, and the nanofiber forms a net-like structure on a solid substrate (X). 9. The structure according to 9 .