JP2000087016A - Composite material with surface which can turn from ultra-water-repellent one to ultra-hydrophilic one - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material with a surface which has water repellency corresponding to an angle of contact with water of 150 deg. or above and upon irradiation with light changes into a hydrophilic one having an angle of contact with water of 10 deg. or below, and can change in wettability upon short-time irradiation with light. SOLUTION: There are provided a composite material with a finely irregular surface exhibiting a water repellency corresponding to an angle of contact with water of 150 deg. or above and changing into one having a hydrophilicity corresponding to an angle of contact with water of 10 deg. or below upon being irradiated with light, and, more particularly, such composite material wherein the composite material contains at least a photocatalyst and a substance which upon exposure to light can be decomposed by the action of the photocatalyst, wherein at least a part of the surface of the composite material has a water repellency corresponding to an angle of contact with water of 150 deg. or above and/or a hydrophilicity corresponding to an angle of contact with water of 10 deg. or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite material that changes from a superhydrophobic surface to a superhydrophilic surface, and more preferably, various patterning techniques, and techniques for forming various elements in a pattern forming portion, for example, printing. About technology.

[0002]

2. Description of the Related Art Materials having a water-repellent surface or materials having a hydrophilic surface have been applied to various applications in recent years. For example, WO 96/29375 discloses a photocatalyst that uses a photocatalyst to improve the surface of a substrate. It has been disclosed that a method for making the surface of a glass super-hydrophilic is applied to a glass surface to provide an antifogging property and a clean surface.

The present inventors have provided a composite material which can be converted into a hydrophilic surface by irradiating light to the water-repellent surface using the photocatalyst. An application was made as Japanese Patent Application No. 10-165392 for the formation of a pattern composed of a conductive surface. However, when making various devices by applying such a water-repellent and hydrophilic pattern, there is a case where it is required to make the water-repellent portion more water-repellent to make the water-based composition more repellent. . Further, in order to shorten the process, it was sometimes required to shorten the irradiation time of light for changing the water-repellent portion to hydrophilicity.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to meet the above-mentioned demands, and an object of the present invention is to provide a water-repellent surface having a contact angle with water of 150 ° or more,
Another object of the present invention is to provide a material which changes its hydrophilicity to a water contact angle of 10 ° or less by light irradiation, and which changes its wettability by short-time light irradiation.

[0005]

Means for Solving the Problems The present inventor has solved the above-mentioned problem by making the surface of a composite material using a material such as a photocatalyst whose wettability changes by light into a fine uneven structure. I learned. Therefore, the composite material of the present invention is a composite material having a surface having a fine uneven structure and exhibiting a water repellency of 150 ° or more in terms of a contact angle with water, and irradiating light to the surface. By doing
It is characterized in that the surface changes to a hydrophilicity of 10 ° or less in terms of a contact angle with water.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The surface of the composite material according to the present invention is characterized by having a fine uneven structure, whereby the wettability suddenly changes unexpectedly due to short-time light irradiation. In addition, the water repellency of the unexposed portions is further increased.

[0008] The roughness of the fine concavo-convex structure can show a water repellency of 150 ° or more in terms of a contact angle with water, and if the roughness changes to a hydrophilicity of 10 ° or less after exposure. There is no particular limitation. However, when the surface roughness is small, sufficient water repellency may not be obtained, and when the surface roughness is too large, sufficient water repellency may not be obtained. Specifically, as a preferable roughness of the fine concavo-convex structure, for example, the center line average roughness can be expressed as 0.1 to 50 μm, more preferably 1 to 10 μm.

In the present invention, the method for forming the fine uneven structure is not particularly limited, and various known methods can be used. Examples of such a method include a polishing treatment, a cutting treatment, a treatment with an acid solution, a treatment with an alkali solution, and electrolysis. Also,
A fine structure may be formed by adding fine particles to the composite material.
Further, the method of forming a thin layer of the composite material of the present invention on not only the unevenness of the composite material itself but also the unevenness of the substrate that can be provided in the preferred embodiment of the present invention,
Alternatively, a method may be used in which a primer layer or the like which can be provided between the substrate and the composite material of the present invention is made uneven to form a thin film of the composite material of the present invention thereon.

Material of Composite Material The composite material of the present invention typically includes, but is not limited to, a photocatalyst described below, and changes the wettability by the action of the photocatalyst.

(Principle of Change in Wettability) In a preferred embodiment of the present invention, a photocatalyst capable of causing a chemical change in a nearby substance (such as a binder) by light irradiation is used.
It is possible to change the wettability of a portion that has been irradiated with light. The mechanism of action of the photocatalyst according to the preferred embodiment of the present invention is not necessarily clear, but carriers generated in the photocatalyst by light irradiation directly change the chemical structure of a binder or the like, or are generated in the presence of oxygen and water. It is considered that the wettability of the composite material surface changes by changing the chemical structure of the binder or the like by the active oxygen species.

In a preferred embodiment of the present invention, the photocatalyst changes the wettability of the light-irradiated portion by using the action of oxidation and decomposition of an organic group or an additive which is a part of the binder to make the portion non-hydrophilic. This causes a large difference in wettability with the irradiated part.

(Photocatalyst Material) Examples of the photocatalyst material preferably used in the present invention include titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO ₂ ) and strontium titanate, which are known as optical semiconductors. (SrTi
O ₃ ), tungsten oxide (WO ₃ ), bismuth oxide (B
Metal oxides such as i ₂ O ₃ ) and iron oxide (Fe ₂ O ₃ ) can be mentioned, and titanium oxide is particularly preferable. Titanium oxide is advantageous in that it has a high band gap energy, is chemically stable, has no toxicity, and is easily available.

As titanium oxide as a photocatalyst, both anatase type and rutile type can be used, but anatase type titanium oxide is preferred. Specifically, for example, anatase titania sol of peptic hydrochloride type (Ishihara Sangyo Co., Ltd., STS-02, average crystallite diameter 7 nm), anatase titania sol of nitric acid deflocculation type (Nissan Chemical, TA-
15, average crystallite diameter of 12 nm).

The smaller the particle size of the photocatalyst, the better, since the photocatalytic reaction occurs efficiently. Those having an average particle size of 50 nm or less are preferable, and more preferably 20 nm or less.
nm or less is preferred.

The amount of the photocatalyst in the composite material is preferably 5 to 60% by weight, more preferably 20 to 40% by weight.

(Binder Component) In a preferred embodiment of the present invention, the binder used in the composite material is a substance which is preferably decomposed by the action of the photocatalyst upon exposure to light. This binder is preferably partially decomposed due to a change in wettability, but has a high binding energy such that the main skeleton is not decomposed by photoexcitation of the photocatalyst. For example, (1) a sol-gel reaction or the like Examples thereof include organopolysiloxanes that exhibit high strength by hydrolyzing or polycondensing chloro or alkoxysilanes, and (2) organopolysiloxanes obtained by crosslinking reactive silicones having excellent water repellency and oil repellency.
Preferred among these are silicones, and more preferred are silicones having a fluoroalkyl group.

In the case of the above (1), the general formula Y _n SiX
One or more hydrolyzed condensates and co-hydrolyzed compounds of the silicon compound represented by _4-n (n = 1 to 3) can be mainly used. In the above general formula, Y can be, for example, an alkyl group, a fluoroalkyl group, a vinyl group, an amino group or an epoxy group, and X can be, for example, a halogen, a methoxyl group, an ethoxyl group, or an acetyl group.

Specifically, methyltrichlorosilane, methyltribromosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltri-t-butoxysilane; ethyltrichlorosilane, ethyltribromosilane, ethyltrichlorosilane Methoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, ethyltri-t-butoxysilane; n
-Propyltrichlorosilane, n-propyltribromosilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltriisopropoxysilane, n-propyltri-t-butoxysilane; n-
Hexyltrichlorosilane, n-hexyltribromosilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-hexyltriisopropoxysilane, n-hexyltri-t-butoxysilane; n-decyltrichlorosilane, n-decyl Tribromosilane,
n-decyltrimethoxysilane, n-decyltriethoxysilane, n-decyltriisopropoxysilane, n-
Decyltri-t-butoxysilane; n-octadecyltrichlorosilane, n-octadecyltribromosilane, n
-Octadecyltrimethoxysilane, n-octadecyltriethoxysilane, n-octadecyltriisopropoxysilane, n-octadecyltri-t-butoxysilane; phenyltrichlorosilane, phenyltribromosilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyl Triisopropoxysilane, phenyltri-t-butoxysilane; tetrachlorosilane, tetrabromosilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, dimethoxydiethoxysilane; dimethyldichlorosilane, dimethyldibromosilane, dimethyldimethoxysilane , Dimethyldiethoxysilane; diphenyldichlorosilane, diphenyldibromosilane, diphenyldimethoxysilane, diphenyldiethoxysilane Phenyl methyldichlorosilane,
Phenylmethyldibromosilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane; trichlorohydrosilane, tribromohydrosilane, trimethoxyhydrosilane, triethoxyhydrosilane, triisopropoxyhydrosilane, tri-t-butoxyhydrosilane; vinyltrichlorosilane, vinyltribromo Silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrit
-Butoxysilane; trifluoropropyltrichlorosilane, trifluoropropyltribromosilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, trifluoropropyltriisopropoxysilane, trifluoropropyltri-t-butoxysilane; γ- Glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ
Glycidoxypropyltriisopropoxysilane, γ
-Glycidoxypropyltri-t-butoxysilane; γ-
Methacryloxypropylmethyldimethoxysilane, γ
-Methacryloxypropylmethyldiethoxysilane,
γ-methacryloxypropyltrimethoxysilane, γ
-Methacryloxypropyltriethoxysilane, γ-
Methacryloxypropyltriisopropoxysilane,
γ-methacryloxypropyltri-t-butoxysilane; γ-aminopropylmethyldimethoxysilane, γ-
Aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropyltri-t-butoxysilane;
γ-mercaptopropylmethyldimethoxysilane, γ-
Mercaptopropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltriisopropoxysilane, γ-mercaptopropyltri-t-butoxysilane; β- (3,4-epoxy Cyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane; and partial hydrolysates thereof; and mixtures thereof.

As the binder, a polysiloxane containing a fluoroalkyl group can be used particularly preferably. Specifically, one or more hydrolyzed condensates of the following fluoroalkylsilanes, Examples include a hydrolytic condensate, and those generally known as a fluorine-based silane coupling agent may be used. _{CF 3 (CF 2) 3 CH} 2 CH 2 Si (OCH 3) 3 CF 3 (CF 2) 5 CH 2 CH 2 Si (OCH 3) 3 CF 3 (CF 2) 7 CH 2 CH 2 Si (OCH 3) _{3 CF 3 (CF 2) 9} CH 2 CH 2 Si (OCH 3) 3 (CF 3) 2 CF (CF 2) 4 CH 2 CH 2 Si (OCH 3) 3 (CF 3) 2 CF (CF 2) 6 _{CH 2 CH 2 Si (OCH 3} ) 3 (CF 3) 2 CF (CF 2) 8 CH 2 CH 2 Si (OCH 3) 3 CF 3 (C 6 H 4) C 2 H 4 Si (OCH 3) 3 CF _{3 (CF 2) 3 (C} 6 H 4) C 2 H 4 Si (OCH 3) 3 CF 3 (CF 2) 5 (C 6 H 4) C 2 H 4 Si (OCH 3) 3 CF 3 (CF 2 _{) 7 (C 6 H 4)} C 2 H 4 Si (OCH 3) 3 CF 3 (CF 2) 3 CH 2 CH 2 SiCH 3 (OCH 3) 2 CF 3 (CF 2) 5 CH 2 CH 2 Si _{H 3 (OCH 3) 2 CF} 3 (CF 2) 7 CH 2 CH 2 SiCH 3 (OCH 3) 2 CF 3 (CF 2) 9 CH 2 CH 2 SiCH 3 (OCH 3) 2 (CF 3) 2 CF ( _{CF 2) 4 CH 2 CH 2} SiCH 3 (OCH 3) 2 (CF 3) 2 CF (CF 2) 6 CH 2 CH 2 SiCH 3 (OCH 3) 2 (CF 3) 2 CF (CF 2) 8 CH 2 _{CH 2 SiCH 3 (OCH 3)} 2 CF 3 (C 6 H 4) C 2 H 4 SiCH 3 (OCH 3) 2 CF 3 (CF 2) 3 (C 6 H 4) C 2 H 4 SiCH 3 (OCH 3 _{) 2 CF 3 (CF 2)} 5 (C 6 H 4) C 2 H 4 SiCH 3 (OCH 3) 2 CF 3 (CF 2) 7 (C 6 H 4) C 2 H 4 SiCH 3 (OCH 3) 2 _{CF 3 (CF 2) 3 CH} 2 CH 2 Si (OCH 2 CH 3) 3 CF 3 (CF 2) 5 CH 2 CH 2 Si (OCH 2 CH 3) 3 C _{3 (CF 2) 7 CH 2} CH 2 Si (OCH 2 CH 3) 3 CF 3 (CF 2) 9 CH 2 CH 2 Si (OCH 2 CH 3) 3 CF 3 (CF 2) 7 SO 2 N (C 2 H ₅₎ C a _{2 H 4 CH 2 Si (OCH} 3) 3 polysiloxane having a fluoroalkyl group as described above by using as the binder, significantly improved water repellency of the non-irradiation part of the composite material, element It exhibits a function of preventing adhesion of the forming composition and the like.

The reactive silicone of the above (2) includes:
A compound having a skeleton represented by the following general formula can be given. — (Si (R ¹ ) (R ² ) O) _n — wherein n is an integer of 2 or more, and R ¹ and R ² are each a substituted or unsubstituted alkyl, alkenyl, aryl or cyanoalkyl having 1 to 10 carbon atoms. Can be a group. Preferably, up to 40 mol% of the total can be vinyl, phenyl or phenyl halide. Also,
It is preferable that R ¹ and / or R ² be a methyl group since the surface energy becomes the smallest, and preferably the methyl group is 60 mol% or more, and at the chain terminal or the side chain,
It has at least one or more reactive groups such as hydroxyl groups in the molecular chain.

Further, a stable organosilicon compound which does not cause a cross-linking reaction such as dimethylpolysiloxane may be mixed with the above-mentioned organopolysiloxane in a binder.

(Other Components Used in Composite Material) The composite material suitably used in the present invention may contain a surfactant to reduce the wettability of the unexposed portion.
The surfactant is not limited as long as it can be decomposed and removed by a photocatalyst. Specifically, preferably, the surfactant is, for example, NIKKOL BL, B manufactured by Nippon Surfactant Industry.
Hydrocarbon surfactants such as C, BO, and BB series; manufactured by DuPont: ZONYL FSN, FSO; manufactured by Asahi Glass: Surflon S-141, 145; manufactured by Dainippon Ink: Megafac F-141, 144; Neos: Futagent F-200, F251; Daikin Industries: Unidyne DS-401, 402; 3M: Florad FC-170, 176, etc., fluorine-based or silicone-based nonionic surfactants. In addition, cationic, anionic and amphoteric surfactants can also be used.

The composite material of the present invention contains other components,
For example, polyvinyl alcohol, unsaturated polyester,
Acrylic resin, polyethylene, diallyl phthalate, ethylene propylene diene monomer, epoxy resin, phenol resin, polyurethane, melamine resin, polycarbonate, polyvinyl chloride, polyamide, polyimide, styrene butadiene rubber, chloroprene rubber, polypropylene, polybutylene, polystyrene, polyvinyl acetate ,
Oligomers and polymers such as nylon, polyester, polybutadiene, polybenzimidazole, polyacrylonitrile, epichlorohydrin, polysulfide, and polyisoprene can be included.

(Method of Forming Composite Material Layer) The composite material of the present invention may be in the form of a layer. In this case, the method of forming the layer of the composite material is not particularly limited. For example, a coating solution containing a photocatalyst is sprayed. It can be formed by applying to a substrate by a method such as coating, dip coating, roll coating, and bead coating. In the case where an ultraviolet-curable component is contained as a binder, a layer of a composition containing a photocatalyst can be formed on a substrate by performing a curing treatment by irradiating ultraviolet rays.

When a coating solution containing a photocatalyst or the like is used, the solvent that can be used for the coating solution is not particularly limited, and examples thereof include alcoholic organic solvents such as ethanol and isopropanol.

The irradiation light for causing the light irradiation photocatalyst to act is not limited as long as the photocatalyst can be excited. Examples of such a material include ultraviolet light, visible light, and infrared light, as well as electromagnetic waves and radiation having a shorter or longer wavelength than these light beams.

For example, when anatase titania is used as the photocatalyst, since the excitation wavelength is 380 nm or less, the photocatalyst can be excited by ultraviolet rays. Mercury lamps, metal halide lamps, xenon lamps, excimer lasers, and other ultraviolet light sources can be used to emit such ultraviolet light.
By changing the irradiation amount or the like, the wettability of the film surface can be continuously changed.

Water repellency and hydrophilicity The composite material of the present invention has a water repellency of 150 ° or more (in the present specification, such a surface is referred to as a super water repellent surface) in terms of a contact angle with water before exposure. , Preferably having a surface exhibiting water repellency of 160 ° or more, and having a hydrophilicity of 10 ° or less (hereinafter, such a surface is referred to as a superhydrophilic surface) in terms of a contact angle with water after exposure. Having a surface exhibiting a hydrophilic property, preferably a hydrophilic property of 5 ° or less.

However, it is not necessary that the surface of the composite material of the present invention always have a contact angle with water of 10 ° or less and / or 150 ° or more. 10 ° to 150 ° in terms of contact angle
It may be a surface showing hydrophilicity between them. By doing so, for example, the contact angle between the composite material surface and water becomes 1
Even when the angle is 0 ° or more, it is advantageous in terms of exposure sensitivity when a material capable of obtaining a sufficient adhesive force is used as a device material.

Pattern, Device and Element Formation The composite material of the present invention is preferably subjected to pattern exposure to produce a pattern-formed body having a pattern of a superhydrophobic portion and a superhydrophilic portion on the same surface of the composite material. be able to. Further, the composite material of the present invention is exposed to light in an amount corresponding to the required hydrophilicity, thereby obtaining a device having a superhydrophobic portion and / or a superhydrophilic portion on the surface of the composite material. be able to. Examples of the device using the composite material of the present invention include a water-repellent film and a snow-prevention film. Furthermore, an element can be formed on the composite material of the present invention by utilizing the specific wettability of the pattern forming body. Examples of such an element using the composite material of the present invention include a printing plate, a lens, and a color filter.

Substrate The composite material of the present invention can be layered on a general substrate. Further, a pattern formed body, device or element may be formed using the composite material on the base.
The material constituting the base can be a material usually used depending on the application, for example, a metal such as aluminum,
Examples include inorganic materials such as glass and ceramics and organic materials such as plastics. From these materials, for example, a plate, a film, a woven fabric, a nonwoven fabric, or the like can be formed and used as a substrate.

[0033]

EXAMPLE 1 20 g of sodium hydroxide was added to 500 g of water to prepare an aqueous sodium hydroxide solution. Next, aluminum (75 x 75 x 0.23 mm, manufactured by Mitsubishi Aluminum) as a base
Was prepared and immersed for 1 hour to carry out a roughening treatment. The surface roughness (center line average roughness) is Dektak 3030 (Sloan
The contact angle of water was measured by CA-Z (manufactured by Kyowa Interface Chemistry). The results are shown below. Center line average roughness (μm) Water contact angle (°) Before treatment After treatment Before treatment After treatment 0.79 3.0 605 or less Then, 3 g of isopropyl alcohol, 0.4 g of organosilane (Toshiba Silicone TSL8113), fluoro, Alkylsilane MF-160E (Tochem Products)
0.04 g, photocatalytic inorganic coating agent ST-K01
(Ishihara Sangyo) 1.5 g was mixed and heated at 100 ° C. for 20 minutes with stirring. This solution was applied onto the aluminum substrate subjected to the unevenness treatment by a spin coating method. This was dried at a temperature of 150 ° C. for 10 minutes to allow hydrolysis and polycondensation reactions to proceed, so that the photocatalyst was firmly fixed in the organopolysiloxane.
A 2 μm photocatalyst-containing film was obtained. Similarly, the results of measuring the center line average roughness and the contact angle of water are shown below. Center line average roughness (μm) Water contact angle (°) 2.6 160 ° Then, a mercury lamp (HAN type 400
NL Nippon Battery Co., Ltd.) at 70 mW / cm ² (365 n
The change with time of the contact angle of water when UV irradiation was performed for 100 seconds at the illuminance of m) was measured.

[0034] Similarly, on this composite material for 90 seconds,
Pattern exposure was performed through a negative photomask in which halftone dots having a diameter of 50 μm were arranged at intervals of 10 μm, to produce a pattern-formed body having superhydrophilicity and superhydrophobicity.

Comparative Example 1 The center line average roughness and the contact angle of water of a composite material produced in the same manner as in Example 1 except that the unevenness treatment by the alkali treatment was not performed are shown below. Center line average roughness (μm) Water contact angle (°) 0.26 120 ° FIG. 1 shows a composite having a fine concavo-convex structure provided on a substrate roughened by the alkali treatment of Example 1 as described above. FIG. 4 is a graph showing the change in wettability according to the light irradiation time for the material and the composite material having no fine unevenness structure provided on a substrate not subjected to a surface roughening treatment such as an alkali treatment in Comparative Example 1. Show. The contact angle of water before exposure is 160 ° for alkali-treated and larger than 120 ° for untreated,
It can be seen that the alkali treatment increased the hydrophobicity.
Furthermore, the time required for the contact angle to become 0 ° by exposure is 90 seconds for an alkali-treated one, and 110 seconds for an untreated one. Can be confirmed to change. Also,
It can be confirmed that the slope of the graph is steep when the alkali treatment is performed. It can be seen that the alkali-treated one changes to super-hydrophilic with a small exposure dose, that is, the alkali treatment increases the sensitivity.

Example 2 A soda lime glass (75 × 75 × 1.1 mm) was prepared as a substrate. Next, a roughening treatment was performed by a sand blast method.
Surface roughness (center line average roughness) is Dektak 3030
(Manufactured by Sloan Technology) and the contact angle of water were measured by CA-Z (manufactured by Kyowa Interface Science). The results are shown below. Center line average roughness (μm) Water contact angle (°) Before treatment After treatment Before treatment After treatment 0.0041 2.1 125 or less Next, 3 g of isopropyl alcohol, 0.4 g of organosilane (Toshiba Silicone TSL8113), fluoro Alkylsilane MF-160E (Tochem Products)
0.04 g, photocatalytic inorganic coating agent ST-K01
(Ishihara Sangyo) 1.5 g was mixed and heated at 100 ° C. for 20 minutes with stirring. This solution was applied onto the roughened blue plate glass substrate by spin coating. This was dried at a temperature of 150 ° C. for 10 minutes to allow hydrolysis and polycondensation reactions to proceed, and a film thickness of 0.6 in which the photocatalyst was firmly fixed in the organopolysiloxane.
A photocatalyst-containing film having a thickness of μm was obtained. Similarly, the results of measuring the center line average roughness and the contact angle of water are shown below. Center line average roughness (μm) Water contact angle (°) 1.3 152 ° Similarly, a pattern is formed on this composite material through a negative photomask in which halftone dots having a diameter of 50 μm are arranged at 10 μm intervals for 90 seconds. Exposure was performed to produce a pattern formed body having super hydrophilicity and super water repellency.

Then, a water-soluble UV-curable resin (ester acrylate resin, AQ-9 manufactured by Arakawa Chemical Industries) 1000
g, 50 g of a curing initiator (Irgacure 1173, manufactured by Ciba Specialty Chemicals) and an aqueous solution of methylene blue (5% by weight) were mixed and applied over the entire surface of the pattern-formed body obtained by the bead coating method. The ink was repelled and selectively applied only to the exposed areas. An indigo pattern in which halftone dots having a diameter of 50 μm were arranged at intervals of 10 μm was obtained.

[0038]

According to the present invention, the contact angle with water is 150 °.
A material having the above water-repellent surface and changing to hydrophilicity with a contact angle of water of 10 ° or less by light irradiation, and changing wettability by short-time light irradiation is provided. be able to.

[Brief description of the drawings]

FIG. 1 shows a composite material of the present invention having a fine uneven structure provided on a substrate roughened by an alkali treatment, and a composite material provided on a substrate not subjected to a surface roughening treatment such as an alkali treatment. 7 is a graph showing a change in wettability according to the light irradiation time for a composite material of a comparative example having no fine uneven structure.

Claims (13)

[Claims] 1. A composite material having a surface having a fine uneven structure and exhibiting a water repellency of 150 ° or more in terms of a contact angle with water, and irradiating the surface with light,
A composite material, wherein the surface changes to a hydrophilicity of 10 ° or less in terms of a contact angle with water. 2. A composite material comprising at least a photocatalyst and a substance decomposed by the action of the photocatalyst upon exposure, wherein at least a part of the surface of the composite material has a contact angle with water. Water repellency of 150 ° or more and / or
Or the composite material according to claim 1 having a hydrophilicity of 10 ° or less. 3. The composite material according to claim 2, wherein said photocatalyst contains titanium oxide. 4. The composite material according to claim 2, wherein the substance decomposed by the action of a photocatalyst upon exposure is silicone. 5. The composite material according to claim 4, wherein said silicone has a fluoroalkyl group. 6. The composite material according to claim 1, wherein the fine unevenness of the composite material has a center line average roughness of 0.1 to 50 μm. 7. The composite material according to claim 6, wherein the fine unevenness structure of the composite material has a center line average roughness of 1 to 10 μm. 8. A pattern-formed body comprising a pattern of a super-hydrophobic part and a super-hydrophilic part on the same surface by pattern exposure of the composite material according to claim 1. 9. A pattern forming body, wherein the composite material according to claim 8 forms a layer, and the layer of the composite material is formed on a substrate. 10. The composite material according to claim 1, which is exposed to light in an amount corresponding to the required hydrophilicity, so that at least a super-water-repellent portion and / or a super-hydrophilic portion are formed on the surface of the composite material. A device, comprising: 11. A device, wherein the composite material of claim 10 forms a layer, wherein the layer of the composite material is formed on a substrate. 12. An element formed on the composite material by utilizing a specific wettability of the pattern forming body according to claim 8. 13. The element according to claim 12, wherein said element is selected from a printing plate, a lens, and a color filter.