JP2011167663A - Method for manufacturing patterned colloidal crystal film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a colloidal crystal film capable of efficiently manufacturing a patterned colloidal crystal film. <P>SOLUTION: The method for manufacturing the colloidal crystal film includes: a step of preparing a dispersion liquid comprising a dispersion medium component containing monomers and polymers and colloidal particles within a range having 0.01-10 μm of average particle size containing less than 20% of a monodisperse degree expressed by [monodisperse degree (unit:%)]=([standard deviation of particle sizes]/[average particle size])×100 and having a reflection peak; a step of preparing a base material having a contact angle within the range having 0-40° to the colloidal dispersion liquid; a step of applying a surface treatment within the range having 0-40° of the contact angle to the colloidal dispersion liquid in a part of the region of the surface of the base material and making a region having 4° or more of a difference of the contact angle of the part of the region after the surface treatment; a step of coating the colloidal dispersion liquid after the surface treatment; and a step of immobilizing the colloidal crystal by polymerizing with the component during coating and obtaining the colloidal crystal film having the formed irregularity of the region having different contact angles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a patterned colloidal crystal film.

  A colloidal crystal film in which colloidal particles are regularly arranged is known to reflect light having a wavelength corresponding to the lattice constant by Bragg diffraction. For example, in the case of a colloidal crystal film in which submicron order colloidal particles are regularly arranged, light having a wavelength in the range of ultraviolet light and visible light to infrared light is reflected. It is also known that when visible light is reflected by such a colloidal crystal film, it is possible to develop so-called structural colors such as iridescence (irised color). Such a colloidal crystal film utilizes the characteristics of the colloidal crystal, a coloring material that develops a structural color, an optical filter that does not transmit light of a specific wavelength, a mirror that reflects specific light, a photonic crystal, It is expected to be applied to optical switches, optical sensors, etc. Therefore, in recent years, various colloidal crystal film production methods have been studied, and specific patterning has also been studied on the obtained colloidal crystal film.

  For example, in WO2005 / 045478 pamphlet (Patent Document 1), particles are contained in a monomer composed of EPTTA (ethoxylated trimethylolpropane triacrylate), spin-coated, and immobilized to produce a colloidal crystal. A method for producing a colloidal crystal film is disclosed, and it is disclosed that patterning is performed on a colloidal crystal film obtained in this manner using a semiconductor lithography technique. However, in the conventional method of patterning a colloidal crystal film as described in Patent Document 1, it is not only necessary to go through a spin coating process in the process of obtaining a colloidal crystal film, but also semiconductor lithography technology is used for patterning. It was necessary and the process was complicated and it was not practical from the viewpoint of cost.

  In JP 2008-303261 A (Patent Document 2), the average particle size is in the range of 0.01 to 10 μm and the monodispersity is 20% or less in the monomer-containing liquid containing one or more monomers. The colloidal particles are dispersed in such a manner that the colloidal particles are contained in a reflection spectrum and have a reflection peak in the reflection spectrum, thereby obtaining a monomer dispersion liquid in which the colloidal crystals in the three-dimensional ordering state are formed. A method for producing a colloidal crystal is disclosed, including a step and a step of polymerizing the monomer in the monomer dispersion to obtain a colloidal crystal fixed with a polymer. However, Patent Document 2 does not directly describe the technical idea of forming a predetermined concavo-convex pattern on a colloidal crystal to be manufactured.

  On the other hand, in Japanese Patent Application Laid-Open No. 2003-181275 (Patent Document 3), there is a method of developing a fine particle dispersion on the surface of a substrate and drying the dispersion medium of the fine particle dispersion from an arbitrary direction to obtain a fine particle arrangement film. It is disclosed that the substrate is formed with a periodic modulation pattern in which the affinity between the substrate surface and the dispersion medium is periodically different. However, the technique described in Patent Document 3 relates to a technique called a pulling method using a fine particle dispersion, and although it is possible to form a stripe pattern in a direction parallel to the pulling direction, such a technique is required. It has not been possible to manufacture a fine particle array film patterned into an arbitrary shape (pattern) such as a pattern other than letters and stripes using technology.

  Further, in pages 3771 to 3775 of “Advanced Materials, vol. 21 (Non-Patent Document 1)” issued in 2009, hemispherical dome-shaped colloidal crystals are discontinuous at arbitrary locations on the substrate surface. A method of sequential alignment is disclosed. However, the method described in Non-Patent Document 1 cannot be used as a method for forming a continuous film.

WO2005 / 045478 pamphlet JP 2008-303261 A JP 2003-181275 A

S. H. Kim et al. , Advanced Materials, vol. 21, 2009, p. 3771-p. 3775

  The present invention has been made in view of the above-described problems of the prior art, and a patterned colloidal crystal that can efficiently and reliably produce a colloidal crystal film whose surface is patterned in an arbitrary design. It aims at providing the manufacturing method of a film | membrane.

  As a result of intensive studies to achieve the above object, the present inventors have found that a dispersion medium component containing at least one selected from the group consisting of monomers and polymers and an average particle size of 0.01 to 10 μm And a colloidal particle having a monodispersity of 20% or less represented by the following formula (1), and the colloidal particle has a reflection peak in a reflection spectrum in the dispersion medium component. The colloidal dispersion dispersed in an arrayed state has an angle difference of 4 ° between the first contact angle and the region having the first contact angle with respect to the colloidal dispersion in the range of 0 ° to 40 °. After forming a coating film by applying to a substrate having a region having a second contact angle as described above, by polymerizing the dispersion medium component in the coating film, the surface of the film obtained is Second contact In order to complete the present invention, it has been found that it is possible to efficiently and reliably produce a colloidal crystal film having irregularities formed in accordance with the shape of a region having corners and the surface patterned in an arbitrary design. It came.

That is, the method for producing a patterned colloidal crystal film according to the present invention has a dispersion medium component containing at least one selected from the group consisting of a monomer and a polymer, and an average particle diameter in the range of 0.01 to 10 μm. And the following formula (1):
[Monodispersity (unit:%)] = ([standard deviation of particle size] / [average particle size]) × 100 (1)
And a colloidal dispersion in which the colloidal particles are dispersed in the dispersion medium component in a three-dimensional regular array state having a reflection peak in a reflection spectrum. The process of preparing
Preparing a substrate having a first contact angle with a surface in the range of 0 ° to 40 ° with respect to the colloidal dispersion;
A surface treatment for changing a contact angle of the partial region of the surface of the base material to the colloidal dispersion in a range of 0 ° to 40 ° is applied to the base material, and the partial region after the surface treatment is applied. A region having a second contact angle at which an angle difference from the first contact angle is 4 ° or more;
Applying the colloidal dispersion to the substrate after the surface treatment to form a coating film;
The dispersion medium component in the coating film is polymerized to fix the colloidal crystals with the polymer, and irregularities are formed according to the shape of the region having the first contact angle and the region having the second contact angle. Obtaining a colloidal crystal film,
It is the method characterized by including.

  In the method for producing a patterned colloidal crystal film of the present invention, one of the first and second contact angles is in the range of 0 ° to 6 °, and the other angle is more than 6 °. It is preferably in the range of 40 ° or less.

  In the method for producing a patterned colloidal crystal film of the present invention, the colloidal crystal film includes a region having an average film thickness in the range of 25 to 45 μm and a region having an average film thickness outside the range. It is preferable to have.

In the method for producing a patterned colloidal crystal film of the present invention, the colloidal dispersion has a viscosity measured at a shear rate of 1000 S ⁻¹ under a temperature condition of 25 ° C. ± 0.1 ° C. It is preferable that it is s.

  Furthermore, in the method for producing a patterned colloidal crystal film of the present invention, it is preferable that in the step of forming the coating film, the colloidal dispersion is applied to the substrate after the surface treatment by spray coating.

  The reason why the colloidal crystal film whose surface is patterned in an arbitrary design can be efficiently and reliably manufactured by the method for manufacturing a patterned colloidal crystal film of the present invention is not necessarily clear, The present inventors infer as follows. That is, first, in the colloidal dispersion used in the present invention, the dispersion medium component contains very uniform colloidal particles having a sufficiently low monodispersity (the particle diameters are very well aligned) as described above. Therefore, the interaction between the particles works uniformly in the dispersion medium component, and the three-dimensional regular array structure is easily formed by the interaction between the particles. Moreover, such colloid dispersion liquid can change the arrangement structure of the particles formed in the monomer dispersion liquid by changing the kind of monomer and colloid particles and their concentration, etc., and the crystal structure (lattice constant, Crystal type etc.) can be easily controlled. When such a colloidal dispersion is applied to a substrate by a coating method such as spray coating or bar coating to form a thin film, the regular arrangement of particles in the colloidal dispersion is once disturbed when applied to the substrate. After that, however, the particles are regularly re-arranged in a self-organized manner due to the thermal motion of the colloidal particles. Therefore, when such a colloidal dispersion is used, colloidal crystals are re-formed on the substrate. On the other hand, in such a colloidal dispersion, the self-organized regular arrangement of colloidal particles is film thickness dependent, and the state of the regular arrangement of particles varies depending on the film thickness of the coating film. The reflectance and structural coloration of the resulting colloidal crystal film vary depending on the film thickness (for example, in the region where the average film thickness of the colloidal crystal film is in the range of 25 to 45 μm, the crystal orientation is in the film thickness direction. A uniform colloidal crystal film having a better orientation is formed (a more regular arrangement is formed), and a colloidal crystal film having a more uniform and higher reflectance tends to be obtained.) Here, the thickness of the colloidal crystal film formed by applying the colloidal dispersion to a substrate and polymerizing (curing) the dispersion medium component in the coating film is determined by applying the colloidal dispersion at the time of application. It depends not only on the amount but also on the wettability of the substrate. In general, in order for the liquid to wet the substrate surface, it is necessary that at least the contact angle is 90 ° or less. Here, the present inventors have examined the contact angle necessary for forming a thin film using the colloidal dispersion. When the contact angle of the substrate is 40 ° or less, the colloidal dispersion is continuous. And a colloidal crystal film having a sufficiently uniform and highly reflective structural color, and a sufficiently thin film having an average film thickness of 60 μm or less can be obtained. Experimentally found that it is possible to do. On the other hand, when the size of the contact angle is 0 ° (generally referred to as complete wetting or extended wetting), the droplet applied to the substrate spreads out and the film thickness decreases with time. Focusing on such characteristics, in the present invention, a base material having a surface having a region where contact angles are partially different in the range of 0 ° to 40 ° is used, and the colloid dispersion liquid is applied to the base material. By applying, the colloidal dispersion liquid wets and spreads on the substrate as a continuous film, but the colloidal dispersion liquid partially wets and spreads on the substrate according to the difference in the contact angle. In other words, the thickness of the region having high wettability with respect to the colloidal dispersion can be reduced, and the thickness of the region having low wettability with respect to the colloidal dispersion can be increased. In this way, by intentionally causing a film thickness distribution in the coating film, the coating film thickness is partially different, and a colloidal crystal film in which irregularities are formed according to the difference in the contact angle of the substrate surface It is presumed that In addition, by causing the film thickness distribution in the coating film in this way, the colloidal particles in the film have different self-organized ordered arrangement states. It is possible to produce a pattern such as a character, a picture, or a pattern by changing the color development. Therefore, in the present invention, the present inventors speculate that the surface of the colloidal crystal film can be patterned into an arbitrary design while being a simple method.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the manufacturing method of the patterned colloidal crystal film which makes it possible to manufacture efficiently and reliably the colloidal crystal film by which the surface was patterned by the arbitrary designs.

It is a graph which shows the relationship between the processing time by UV ozone treatment confirmed in Test Example 1, and the contact angle with respect to the colloid dispersion liquid of the surface of a black coating steel plate. 6 is a graph showing a relationship between a treatment time by UV ozone treatment confirmed in Test Example 2 and a contact angle with respect to a colloidal dispersion on the surface of a resin substrate. 2 is a photograph of a colloidal crystal film (thin film) obtained in Example 1. 4 is a photograph of a colloidal crystal film (thin film) obtained in Example 1 taken from an angle different from that shown in FIG. 3. It is a graph of the reflection spectrum of the area | region where the kingfisher pattern of the colloidal crystal film (thin film) obtained in Example 1 appears, and the area | region outside the said pattern.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

The method for producing a patterned colloidal crystal film of the present invention includes a dispersion medium component containing at least one selected from the group consisting of a monomer and a polymer, an average particle diameter in the range of 0.01 to 10 μm, and the following: Formula (1):
[Monodispersity (unit:%)] = ([standard deviation of particle size] / [average particle size]) × 100 (1)
And a colloidal dispersion in which the colloidal particles are dispersed in the dispersion medium component in a three-dimensional regular array state having a reflection peak in a reflection spectrum. Preparing (A),
Preparing a base material having a first contact angle in a range of 0 ° to 40 ° with respect to the colloidal dispersion surface;
A surface treatment for changing a contact angle of the partial region of the surface of the base material to the colloidal dispersion in a range of 0 ° to 40 ° is applied to the base material, and the partial region after the surface treatment is applied. A step (C) in which a difference in angle with the first contact angle is a region having a second contact angle that is 4 ° or more;
A step (D) of applying the colloidal dispersion to the surface-treated substrate to form a coating film;
The dispersion medium component in the coating film is polymerized to fix the colloidal crystals with the polymer, and irregularities are formed according to the shape of the region having the first contact angle and the region having the second contact angle. Obtaining a colloidal crystal film (E),
It is the method characterized by including. Hereinafter, steps (A) to (E) will be described separately.

  First, the step (A) will be described. Step (A) is a step of preparing the colloidal dispersion as described above.

  The dispersion medium component in such a colloidal dispersion contains at least one selected from the group consisting of monomers and polymers. As such a dispersion medium component, it is preferable to use one composed of one or more monomers from the viewpoint of more efficiently forming a colloidal crystal film. Such a monomer is not particularly limited as long as it can disperse the colloidal particles in the three-dimensional ordered arrangement state, and a preferable example thereof is an acrylic monomer.

  Moreover, as such a monomer, a hydrophilic monomer is preferable, and a hydrophilic monomer containing a nonionic hydrophilic group other than an ionic functional group such as an acid or a base is more preferable. Examples of such nonionic hydrophilic groups include hydroxyl groups and ethylene glycol groups. In the case of monomers containing ionic functional groups such as acids and bases, when forming colloidal crystals, the monomers tend to affect the interaction between colloidal particles, making it difficult to form a three-dimensional array structure. It is in. In addition, when a hydrophobic monomer that does not dissolve in water is used, the surface of the colloidal particles is hydrophilic, making it difficult for the colloidal particles to aggregate and disperse uniformly. Tends to be difficult to form.

  Such a hydrophilic monomer is not particularly limited, and a known hydrophilic monomer can be appropriately used. For example, polyethylene glycol (meth) acrylate, polyethylene glycol di (meth) acrylate, polyethylene having different ethylene glycol chain lengths can be used. Glycol tri (meth) acrylate, polypropylene glycol (meth) acrylate, polypropylene glycol di (meth) acrylate, polypropylene glycol tri (meth) acrylate, 2-hydroxyethyl (meth) acrylate, or 2-hydroxypropyl (meth) acrylate, Examples include acrylamide and methylenebisacrylamide.

  Among such hydrophilic monomers, polyethylene glycol (meth) acrylate, polyethylene glycol di (meth) acrylate, polyethylene glycol tri (meth) acrylate, polypropylene glycol (meth) acrylate, polypropylene glycol di (meth) acrylate and polypropylene Glycol tri (meth) acrylate is particularly preferred. Such polyethylene glycol acrylates or polypropylene glycol acrylates can use various monomers having different chain lengths of ethylene or propylene glycol, and the hydrophilicity can be controlled by the chain length. It tends to be able to control the state more efficiently. When the dispersion medium component is composed of the hydrophilic monomer, one kind of the hydrophilic monomer may be used alone, or two or more kinds may be used in combination.

  Furthermore, when the dispersion medium component contains a hydrophilic monomer, the content ratio of the hydrophilic monomer is 85% by mass or more (more preferably 90% by mass to 100% by mass) with respect to the total amount of the monomer and the polymer. ) Is preferable. When the content ratio of the hydrophilic monomer is less than the lower limit, it tends to be difficult to form a colloidal crystal.

  The monomer preferably contains a polyfunctional monomer having a plurality of ethylenic double bonds and a monofunctional monomer having one ethylenic double bond. By using a combination of such a polyfunctional monomer and a monofunctional monomer, there is a tendency that sufficient mechanical strength and sufficient adhesion to a substrate or the like are obtained when immobilized with a polymer.

  As such a polyfunctional monomer, a (meth) acrylic acid ester monomer having at least one selected from the group consisting of an ethylene glycol chain and a propylene glycol chain and a plurality of (meth) acrylic groups is preferable. Use of a (meth) acrylic acid ester monomer containing at least one selected from the group consisting of ethylene glycol chain and propylene glycol chain as the polyfunctional monomer, so that the polyfunctional monomer has sufficient hydrophilicity Therefore, the colloidal crystal film tends to be formed more efficiently. Moreover, as a (meth) acrylic acid ester monomer used as the said polyfunctional monomer, what has two or three (meth) acryl groups is more preferable. In addition, as the (meth) acrylic acid ester monomer containing an ethylene glycol chain and / or a propylene glycol chain used as such a polyfunctional monomer, various monomers having different chain lengths of the ethylene glycol chain or the propylene glycol chain are used. can do.

  In addition, as the (meth) acrylic acid ester monomer used as such a polyfunctional monomer, polyethylene glycol di (meth) acrylate, polyethylene glycol trichloride is used from the viewpoint of easy availability and formation of a three-dimensional ordered array structure. (Meth) acrylate, polypropylene glycol di (meth) acrylate, and polypropylene glycol tri (meth) acrylate are preferred. As such a polyfunctional monomer, one kind may be used alone, or two or more kinds may be mixed and used.

  The monofunctional monomer is a monomer having one ethylenic double bond. Such a monofunctional monomer is not particularly limited, and a known monofunctional monomer can be appropriately used. For example, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, 2-hydroxyethyl acrylate (HEA), Examples include 2-hydroxypropyl acrylate (HPA), 2-hydroxyethyl methacrylate (HEMA), styrene monomer, ethyl acrylate, and butyl acrylate.

  Such monofunctional monomers include polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, 2-hydroxyethyl acrylate (HEA), 2-hydroxypropyl acrylate (HPA), 2 from the viewpoint of availability. -Hydroxyethyl methacrylate (HEMA) is particularly preferred. In addition, you may use such a monofunctional monomer individually by 1 type or in mixture of 2 or more types.

  Moreover, when using combining the said polyfunctional monomer and a monofunctional monomer, the content rate of the said polyfunctional monomer is 1-95 mass% (more preferably) with respect to the total amount of the said polyfunctional monomer and a monofunctional monomer. 3 to 90% by mass). If such a content ratio is less than the lower limit, the hardness of the polymer obtained after polymerization tends to be low, and the strength as a film tends not to be sufficiently maintained. On the other hand, if the upper limit is exceeded, the hardness of the polymer obtained after polymerization is low. The colloidal crystal fixed with the resulting polymer tends to become brittle.

  Moreover, it does not specifically limit as said polymer, The acrylic polymer generally used for a coating material, a urethane polymer, etc. can be used suitably. As such a polymer, a polymer (more preferably an acrylic polymer) formed by polymerizing the above-mentioned monomers can be suitably used.

  The dispersion medium component is not particularly limited as long as it contains at least one selected from the group consisting of the monomer and the polymer, and contains only the monomer and / or polymer. Alternatively, a solvent may be contained together with the monomer and / or polymer. Such a solvent can also be used effectively when adjusting the viscosity of the dispersion. Moreover, as such a solvent, although it does not restrict | limit, hydrophilic solvents, such as alcohol, can be used suitably. In addition, when the colloidal dispersion liquid contains a solvent, in order to prevent the crystal structure from changing due to the colloidal crystal being broken or distorted as the solvent evaporates during immobilization, The solvent content is preferably 30% by mass or less (more preferably 20% by mass or less, and still more preferably 10% by mass or less).

  The colloidal particles in the colloidal dispersion are particles having an average particle size in the range of 0.01 to 10 μm (more preferably 0.05 to 1.0 μm). If the average particle size of such particles is less than the lower limit, the cohesive force between the particle surfaces tends to be strong, and it tends to be difficult to disperse uniformly in the colloidal dispersion. On the other hand, if the upper limit is exceeded, the particles settle. Tends to be difficult to disperse uniformly in the colloidal dispersion.

Further, the colloidal particles have the following formula (1):
[Monodispersity (unit:%)] = ([standard deviation of particle size] / [average particle size]) × 100 (1)
The monodispersity represented by the particle is 20% or less. That is, the particles are particles having such a monodispersity and a very uniform particle size. In the present invention, such highly uniform particles are used for the colloidal particles, and therefore, when dispersed in the dispersion medium component, a three-dimensional ordered array structure is easily formed by the interaction between the particles. It becomes possible to make it. In addition, as such particles tend to have higher characteristics as the monodispersity becomes smaller, the monodispersity is 10% (more preferably 5%) or less. More preferred.

  Further, the material of such colloidal particles is not particularly limited, and is selected from known organic materials, inorganic materials, organic-inorganic composite materials, and inorganic-inorganic composite materials according to the field to which the obtained colloidal crystal film is applied. Can be appropriately selected and used. Examples of such organic materials include polystyrene and derivatives thereof, and organic polymer materials such as acrylic resins. Examples of the inorganic materials include silica (silicon dioxide), alumina (aluminum oxide), titania ( And titanium oxide) and zinc oxide. Examples of the organic-inorganic composite material include core-shell type organic-inorganic composite particles in which particles made of polystyrene and its derivatives or acrylic resin are covered with titanium oxide, cerium oxide, zinc oxide or the like. Examples of the inorganic-inorganic composite material include core-shell type inorganic-inorganic composite particles in which particles made of silica are covered with titanium oxide, cerium oxide, zinc oxide, or the like. Furthermore, as a material for such colloidal particles, silica, polystyrene, and polymethyl methacrylate are particularly preferable from the viewpoint that monodisperse particles can be easily synthesized. In addition, you may use the material of such a particle individually by 1 type or in combination of 2 or more types.

  Examples of such colloidal particles include polystyrene particles synthesized by emulsion polymerization or polymethyl methacrylate particles (manufactured by Dow Chemical, Polyscience, Nippon Synthetic Rubber, Sekisui Chemical, etc.), In addition, silica particles synthesized by a Stover method (manufactured by Nippon Shokubai Co., Ltd., produced by catalytic conversion) can be used as appropriate. Alternatively, monolayer particles (template particles) may be coated with a layered compound by the Layer-By-Layer method to form bilayer structured particles or hollow particles, which may be used as the colloidal particles.

  The content of such colloidal particles is preferably 5 to 50% by volume, and more preferably 10 to 40% by volume in the colloidal dispersion. When the content of such colloidal particles is less than the above lower limit, it tends to be difficult to make the colloidal particles into a three-dimensional ordered arrangement state when dispersed in the dispersion medium component. The concentration of colloidal particles becomes too high, and it tends to be difficult to control the arrangement structure of the colloidal particles.

  In the colloidal dispersion, the colloidal particles are dispersed in the dispersion medium component in a three-dimensional regular array state having a reflection peak in a reflection spectrum. Here, the “three-dimensional regular array state having a reflection peak in the reflection spectrum” referred to in the present invention refers to a state in which the reflection spectrum is measured and the presence of the reflection peak by Bragg diffraction is confirmed. Means an inflection point when the intensity of reflected light increases or decreases with a change in wavelength with respect to a non-reflective state, and is different from noise in which the intensity of reflected light increases or decreases. In addition, as a method for measuring such a reflection spectrum, an ordinary spectrophotometer can be used. In the present invention, however, a method for measuring using a trade name “Multi-channel spectrometer Fastvert” manufactured by Soma Optical Co., Ltd. Is adopted. Examples of such a three-dimensional regular array structure include a face-centered cubic structure and a body-centered cubic structure. The peak is preferably a peak at a wavelength between 350 and 1600 nm (“Fastvert S-2650” for wavelengths of 350 to 1050 nm and “Fastvert S-2710” for wavelengths of 900 to 1600 nm).

  In addition, the average distance between the closest particles of the colloidal particles in such a three-dimensional ordered arrangement state is not particularly limited, but is preferably in the range of 0.01 to 10 times the average particle diameter of the colloidal particles. More preferably, it is in the range of 0.05 to 2 times. If the average distance between the closest particles is less than the lower limit, the volume of the polymer matrix tends to decrease and the strength tends to decrease. On the other hand, if the upper limit is exceeded, it is difficult to arrange colloidal particles in a three-dimensional regular array. Tend to be.

  Further, as a method of dispersing colloidal particles in the dispersion medium component in a three-dimensional regular arrangement state having a reflection peak in a reflection spectrum (hereinafter, simply referred to as “dispersion method”), the colloidal particles are dispersed and the 3 Any method can be used as long as it can be in a dimensionally ordered state. For example, a method of applying ultrasonic waves for a long time, a method of stirring for a long time, a method of heating, or adding a solvent such as alcohol to disperse The method of making it etc. can be employ | adopted suitably. In such a dispersion method, in order to bring the colloidal particles into a three-dimensional regular array state, for example, a method of measuring the reflection spectrum every predetermined time and repeating the dispersion step until a reflection peak appears may be adopted. Good.

  Further, when adopting a method of applying ultrasonic waves as such a dispersion method, although it varies depending on the type of monomer used, the viscosity of the colloidal dispersion, the concentration of the colloidal particles, etc., the colloidal particles are more reliably used. From the viewpoint of arranging in the three-dimensional regular arrangement state, it is preferable to apply ultrasonic waves for 0.5 to 24 hours (more preferably 1 to 10 hours). If the application time of the ultrasonic wave is less than the lower limit, it tends to be difficult to arrange the colloidal particles in a three-dimensional ordered arrangement state. On the other hand, if the upper limit is exceeded, the dispersion process takes more time than necessary. The working efficiency tends to decrease.

  Moreover, the frequency in particular of such an ultrasonic wave is not restrict | limited, What is necessary is just 16 kHz or more, and it is preferable to set it as 20-200 kHz. If the frequency is less than the lower limit, it tends to be difficult to arrange the colloidal particles in a three-dimensional ordered arrangement state. On the other hand, if the frequency exceeds the upper limit, the colloidal particles are likely to aggregate, and again the three-dimensional ordered arrangement state. It tends to be difficult to arrange them.

  Moreover, it does not restrict | limit especially as temperature conditions at the time of applying such an ultrasonic wave, However, It is preferable that it is 0-80 degreeC (preferably 10-60 degreeC). If such temperature condition is less than the lower limit, the dispersion efficiency of the colloidal particles tends to decrease.On the other hand, if the upper limit is exceeded, the polymerization reaction of the monomer proceeds, the dispersion medium component is modified, or It tends to be difficult to form colloidal crystals due to changes in the component composition.

  Further, in the case of adopting a method of adding a solvent such as alcohol as the dispersion method, from the viewpoint of more surely arranging the colloidal particles in the three-dimensional regular array state, methanol, ethanol, propanol, butanol are used as the solvent. Etc. are preferably used. In addition, the content of such a solvent is preferably 30 parts by mass or less with respect to 100 parts by mass of a mixture in which colloidal particles are contained in a hydrophilic monomer. If the content of such a solvent exceeds the above upper limit, when the monomer is polymerized to form a polymer, it tends to be a gel containing the solvent.

In the colloidal dispersion, the viscosity is preferably 10 to 100 mPa · s. Here, as the “viscosity”, a “fluid spectrometer ARES” manufactured by Rheometrics Scientific is used as a rotational viscometer, and a cone plate having a diameter of 25 mm and a cone angle of 0.1 rad is used. The viscosity value measured under the conditions of 25 ° C. ± 0.1 ° C. and shear rate: 1000 S ⁻¹ is adopted. When the viscosity is less than the lower limit, dripping becomes remarkable, and it is difficult not only to uniformly apply to a shape, but it is also difficult to secure a film thickness that can sufficiently function as a colloidal crystal film. On the other hand, when the above upper limit is exceeded, it is difficult to obtain a sufficiently smooth colloidal crystal film showing good color development, and furthermore, the reflection spectrum of the resulting colloidal crystal film has a sufficiently high degree of reflection. There is a tendency that a reflection peak of the reflectance (a reflection peak whose reflection peak intensity exceeds 30%) cannot be obtained. In addition, the viscosity of such a colloidal dispersion is 20 to 60 mPa · s because it is possible to efficiently obtain a smoother and more sufficiently colored colloidal crystal film from the same viewpoint. It is more preferable. A colloidal dispersion having such a viscosity can be suitably used when a spray coating method is used as a coating method on a substrate.

  In addition, as a method of adjusting the viscosity of such a colloidal dispersion to the above range, a method of adjusting the viscosity to the above range by appropriately selecting the type of monomer in the dispersion medium component, When using two or more monomers, a method of adjusting the viscosity of the entire colloidal dispersion to the above-mentioned range by containing at least one monomer having a low viscosity, and reducing the viscosity of the colloidal dispersion by mixing a solvent. And a method using a viscosity modifier generally used in paints. Such a low-viscosity monomer is not particularly limited, and can be appropriately selected from the aforementioned monomers and used.

  Such a colloidal dispersion may contain a photopolymerization initiator. Thus, by allowing the colloidal dispersion to contain a photopolymerization initiator, when the monomer is polymerized, it can be efficiently polymerized by irradiation with ultraviolet light or the like. Such a photopolymerization initiator is not particularly limited, and a known photopolymerization initiator can be used as appropriate. Examples thereof include sulfur compounds such as carbamate, organic peroxides such as benzoyl peroxide, azo compounds, transition metal complexes, polysilane compounds, and dye sensitizers.

  Further, the amount of such a photopolymerization initiator added is not particularly limited, but can be appropriately changed according to the type of monomer used, but is 0.1 to 5% by mass (more preferably) with respect to the colloidal dispersion. Is preferably 0.5-3 mass%. When the addition amount of such a photopolymerization initiator is less than the lower limit, it tends to be difficult to polymerize the monomer by irradiating light such as ultraviolet light, and on the other hand, when the upper limit is exceeded, the colloid is in a dispersion state. It tends to be difficult to form crystals.

  Furthermore, the colloid dispersion liquid may appropriately contain various additives that can be generally added to paints, such as pigments and UV absorbers, as long as the effects of the present invention are not impaired.

  Next, the step (B) will be described. Step (B) is a step of preparing a base material having a first contact angle in the range of 0 ° to 40 ° with respect to the colloidal dispersion.

  The material of such a substrate is not particularly limited as long as the contact angle of the surface on the substrate with respect to the colloidal dispersion can be adjusted to 0 ° or more and 40 ° or less. Therefore, as such a substrate, for example, a substrate made of glass, metal, or various plastics can be used. In addition, the shape of such a substrate is not particularly limited, and may be various shapes such as a plate shape, a circular shape, and a spherical shape. In the present invention, since the colloidal dispersion is used, it is possible to form a colloidal crystal film even if the surface of the substrate is a curved surface. A method for measuring such a “contact angle” will be described later.

  Moreover, in such a base material, a substrate whose surface contact angle with respect to the colloid dispersion liquid is in the range of 0 ° to 40 ° from the beginning may be used, or the contact angle with respect to the colloid dispersion liquid may be changed. You may use what made the base material surface the contact angle with respect to the said colloid dispersion liquid in the range of 0 to 40 degree. The treatment for changing the contact angle of the substrate surface with respect to the colloidal dispersion is not particularly limited, and a known method capable of changing the wettability with respect to the colloidal dispersion on the surface of the substrate is appropriately used. For example, the chemical treatment and the physical treatment described in Chapter 9 of Akira Nakajima “Control of Wetting of Solid Surface” (Uchida Otsukuru, 2007) Chapter 9 can be used as appropriate. For example, as a method for improving the wettability of the substrate surface to the colloidal dispersion so that the contact angle of the surface has a desired size of 0 ° to 40 °, the substrate is wetted with respect to the colloidal dispersion. By improving the wettability of the surface of the base material to the colloidal dispersion by applying a treatment (such as a hydrophilization treatment, such as plasma treatment or UV ozone treatment), the contact angle of the surface with the colloidal dispersion is increased. A method may be employed in which the angle is 0 ° or more and 40 ° or less. Further, as a method for reducing the wettability of the surface of the base material to the colloidal dispersion so that the contact angle of the surface has a desired contact angle in the range of 0 ° to 40 °, for example, ethanol, n -Wetting of the surface of the substrate with a becot impregnated with alcohol such as propanol, isopropanol, n-butanol, etc., reduces the wettability of the substrate surface to the colloidal dispersion, and the contact angle of the surface is 0 ° or more 40 The contact angle of the surface can be reduced by reducing the wettability of the surface of the substrate to the colloidal dispersion by applying a water repellency treatment with a silane coupling agent, or a method of obtaining a contact angle of a desired size in the range of A method of setting the contact angle to a desired size in the range of 0 ° to 40 ° may be used. Thus, the base material which has the 1st contact angle of the desired angle of the range of 0 degree or more and 40 degrees or less is easily obtained by performing the process which changes the contact angle with respect to the colloid dispersion liquid of the base-material surface. Can do. Note that when the first contact angle exceeds 40 °, a sufficiently thin colloidal crystal film cannot be produced.

  Next, process (C) is demonstrated. In the step (C), after the surface treatment, the substrate is subjected to a surface treatment for changing a contact angle of the partial region of the surface of the substrate with respect to the colloidal dispersion in a range of 0 ° to 40 °. The partial region is a step having a second contact angle at which an angle difference from the first contact angle is 4 ° or more.

  As described above, as the surface treatment method for changing the contact angle of the partial region of the surface of the substrate with respect to the colloidal dispersion in the range of 0 ° or more and 40 ° or less, the above-mentioned group is applied to an arbitrary region. What is necessary is just to perform the process which changes the contact angle with respect to the colloid dispersion liquid of the material surface, for example, by masking an arbitrary area | region and performing physical treatments, such as a plasma process and UV ozone treatment, with respect to the area | region which is not masked Applying surface treatment to improve the hydrophilicity of the unmasked area and changing the contact angle of the unmasked area in the range of 0 ° to 40 °, or after masking some areas The base material is covered with a becot impregnated with alcohol such as ethanol, n-propanol, isopropanol, n-butanol through a mask. A method of improving the water repellency of the unmasked region by wiping the surface locally to increase the contact angle and changing the contact angle of the unmasked region in the range of 0 ° to 40 °, By partially applying a water repellency treatment with a silane coupling agent to locally increase the contact angle, the water repellency of the treated region is improved and the contact angle is increased in the range of 0 ° to 40 °. The contact method of the region where the metal rod is in contact in the range of 0 ° or more and 40 ° or less by increasing the contact angle of the region where the metal rod is contacted by locally bringing the metal rod into contact with the surface of the substrate. A method of changing the angle or the like can be appropriately employed. As the metal rod, an atomic force microscope probe may be used. As such a surface treatment method, from the viewpoint that the contact angle of a part of the region can be easily changed, physical treatment such as plasma treatment or UV ozone treatment is performed while masking an arbitrary region. It is preferable to employ a method for performing the treatment.

  Moreover, in such a process (C), the said surface treatment is given to the said base material, The difference of an angle with said 1st contact angle is 4 degrees or more in the said one part area | region after the said surface treatment. It is set as the area | region which has the 2nd contact angle which becomes. When the difference in angle between the second contact angle and the first contact angle is less than 4 °, the colloidal dispersion liquid is wetted in the region having the first contact angle and the region having the second contact angle. There is no significant change in the spreading method, a colloidal crystal film having sufficient unevenness cannot be formed, and patterning cannot be performed sufficiently.

  In order to cause such a difference in angle, for example, when a physical treatment such as plasma treatment or UV ozone treatment as described above is adopted, the time for performing the surface treatment is appropriately changed to change the angle difference. On the other hand, when adopting a method of partially applying the water repellency treatment with the silane coupling agent as described above, the type of the coupling agent is appropriately changed, You may make it an angle difference become a predetermined magnitude | size. In this way, by setting the difference between the second contact angle and the first contact angle to be 4 ° or more, the substrate has a region having the first contact angle on the surface and the second contact angle. And the areas of wettability with respect to the colloidal dispersion are sufficiently different depending on the areas. It becomes possible to change the film thickness of the coating film of the dispersion. Thus, by setting the difference between the second contact angle and the first contact angle to be 4 ° or more, it becomes possible to intentionally form a film thickness distribution, and to easily form an uneven colloidal crystal film. Can be manufactured. On the other hand, in the colloidal dispersion used in the present invention, colloidal particles are regularly arranged in a self-organized manner, and such an ordered arrangement depends on the film thickness of the coating film of the dispersion. Therefore, in the present invention, it is possible to form irregularities and change the structural color depending on the thickness of the film, and it is possible to obtain a patterning film having a high degree of design. Thus, in the present invention, it is possible to change the structural color of the colloidal crystal film formed on the substrate by locally changing the wettability of the substrate surface to the colloidal dispersion. Thus, patterning can be performed by a simple process without performing a complicated process as in conventional semiconductor lithography.

  In such surface treatment, one of the first and second contact angles is set to 0 ° to 6 °, and the other angle is more than 6 ° to 40 ° (more preferably 10 ° or more). 30 ° or less). The surface treatment method is not particularly limited so as to satisfy such a contact angle condition. For example, a base material having a surface with a first contact angle with respect to the colloidal dispersion of more than 6 ° and 40 ° or less is used. Physical treatment such as plasma treatment or UV ozone treatment is performed while masking a part of the substrate surface, and the contact angle of the unmasked region is set to 0 ° to 6 °, and the second contact angle is set to 0. A method in which the angle is not less than 6 ° and not more than 6 ° may be adopted. A mask having a first contact angle of 0 ° or more and 6 ° or less is masked after masking a part of the substrate surface. Then, the surface of the substrate is wiped with a becot impregnated with alcohol such as ethanol, n-propanol, isopropanol, n-butanol, etc., and the contact angle of the unmasked region is set to more than 6 ° and 40 ° or less. contact And a substrate having a surface with a first contact angle of 0 ° or more and 6 ° or less, and partially subjected to water repellency treatment with a silane coupling agent. You may employ | adopt the method which makes the contact angle of the area | region which performed the process more than 6 degrees and 40 degrees or less, and makes a 2nd contact angle more than 6 degrees and 40 degrees or less. Note that the contact angle of 6 ° here has a large contact angle measurement error near 0 ° in the contact angle meter. Therefore, if the angle is less than this, it is completely wet. Alternatively, the value is determined as being almost completely wet. That is, the contact angle of 6 ° is an angle obtained in order to achieve a state close to complete wetting and a state of adhesion wetting on the same surface, and so-called complete wetting in a region where the contact angle is 6 ° or less. A state close to is formed. Therefore, by changing the contact angle of a partial region of the surface in this way, one of the first and second contact angles is set to 0 ° or more and 6 ° or less, and the other angle is over 6 °. When the contact angle is 0 ° or less (more preferably 10 ° or more and 30 ° or less), in a region where the contact angle is 0 ° or more and 6 ° or less, a state close to so-called complete wetting is formed, and the colloidal dispersion is more likely to spread. On the other hand, in a region where the contact angle is more than 6 ° and not more than 40 °, so-called wettability called adhesion wetting is achieved, and the way in which the colloidal dispersion spreads is slower than the region where the contact angle is 0 ° or more and 6 ° or less. . And it becomes possible to change the film thickness of a coating film more easily by utilizing the difference in the wet spreading method of such a colloid dispersion liquid, and, thereby, in the range of 25-45 micrometers suitable in this invention. It is also possible to produce a colloidal crystal film having a region having an average film thickness and a region having an average film thickness outside the above range.

In addition, regarding the contact angle of the surface of the substrate, referring to “Physics of surface tension” (issued by Yoshioka Shoten, 2003), the thickness e of a large water droplet (puddle) is expressed by the following formula:
e = 2κ ⁻¹ · sin (θ / 2)
(In the formula, e represents the thickness of the water droplet (film thickness of the coating film), θ represents the contact angle, and κ ⁻¹ represents the capillary length.)
It is described that the film can be obtained by calculating, and the film cannot be maintained at a film thickness smaller than the film thickness e obtained by such calculation, It is described that it becomes. According to the same book, the capillary length of liquid κ ^-1 is generally 2 mm, such as water. Here, assuming that κ ⁻¹ is 1 mm and the film thickness e is calculated for several contact angles, the film thickness e is 105 μm at θ = 6 °, the film thickness e is 518 μm at θ = 30 °, and θ The film thickness e is 684 μm at = 40 °, and the film thickness e is 1000 μm at θ = 60 °. According to the same book, when κ ⁻¹ is 1 mm, a sufficiently thin film of 60 μm or less cannot be maintained even when θ is 6 °. However, in the colloidal dispersion used in the present invention, a film having an average film thickness of 50 μm can be formed even on a substrate having a contact angle of about 30 ° with respect to the colloidal dispersion. Thus, in the present invention, a colloidal crystal film having a sufficiently thin average film thickness (preferably 60 μm or less) is produced even when a substrate having a contact angle of 40 ° or less is used in relation to the colloid dispersion used. From this viewpoint, the upper limit of the contact angle of the substrate with respect to the colloidal dispersion is set to 40 °.

  Since the contact angle of the surface of the base material with respect to the colloidal dispersion generally has a tendency to gradually change over time after the surface treatment, in the present invention, the colloidal dispersion of the base material As the “contact angle with respect to the dispersion liquid”, a value measured 30 minutes after the surface treatment is applied. Further, in the present invention, the “contact angle” is measured according to JIS standard R3257 “Testing method for wettability of substrate glass surface”, and the product name “CA” manufactured by Kyowa Interface Chemical Co., Ltd. is used as a measuring device. -A "and using a 2 mL droplet (dispersion) under a temperature condition of 23 ° C., about 15 seconds later, the substrate surface, the droplet, and the air A method is adopted in which the angle formed by the straight line connecting the contact point and the vertex of the droplet with the substrate surface is read and the value of the contact angle is measured by doubling the angle value. In addition, such “contact angle” is measured when 30 minutes have passed after the surface treatment when the substrate is surface-treated as described above, and otherwise the substrate is used as it is. taking measurement. Furthermore, since the contact angle with respect to such a colloidal dispersion does not change significantly for about 1 hour after the surface treatment, the substrates obtained in the step (B) and the step (C) are subjected to the surface treatment, respectively. After that, it is preferable to use within one hour.

  Next, process (D) is demonstrated. Step (D) is a step in which the colloidal dispersion is applied to the surface-treated substrate to form a coating film.

  The method for applying such a colloidal dispersion to a substrate is not particularly limited, and a known method capable of applying a liquid to a solid surface can be used as appropriate, for example, spray coating, dip coating, and the like. Method, roll coating method, bar coating method, doctor blade method and the like can be used. However, the spin coating method is difficult to apply because it has a particle arrangement (crystallization) effect due to a shearing force generated by a centrifugal force, and it is difficult to obtain a color difference due to the wettability of the substrate surface.

In addition, as a method of applying such a colloidal dispersion to a base material, spraying can be performed on a base material having a curved surface, and it is easy to obtain uniform color development of colloidal crystals. It is more preferable to use a coating method. The spray coating method is not particularly limited, and may be spray coating using an air spray gun, or may be spray coating using an airless gun. In addition, various conditions such as the atmosphere and temperature at the time of such spray coating are not particularly limited, and known spray coating conditions can be adopted as appropriate, depending on the type of monomer in the colloidal dispersion to be used, etc. What is necessary is just to adjust suitably. Further, when the spray coating method is used in this way, the coating can be applied more uniformly and a coating having a sufficient thickness can be obtained at 25 ° C. ± 0.1 as described above. It is preferable to use a colloidal dispersion having a viscosity of 10 to 100 mPa · s (more preferably 20 to 60 mPa · s) measured at a shear rate of 1000 S ⁻¹ under a temperature condition of ° C.

  In addition, after forming the coating film by applying the colloidal dispersion to the substrate after the surface treatment in this way, sufficient unevenness is formed by utilizing the difference in the wetting and spreading of the colloidal dispersion. In order to achieve self-organization and rearrangement of particles in the coating film, it is preferable to stand for a predetermined time. The time for allowing the coating film to stand in this manner varies depending on the type of the dispersion medium component used and cannot be generally specified, but it is a time for sufficiently forming irregularities and sufficiently rearranging the particles. For example, it may be about 10 minutes or more (more preferably about 10 minutes to 1 hour).

  Next, process (E) is demonstrated. In the step (E), the dispersion medium component in the coating film is polymerized to fix the colloidal crystal with the polymer, and the shape of the region having the first contact angle and the region having the second contact angle is obtained. This is a step of obtaining a colloidal crystal film in which corresponding irregularities are formed.

  The method for polymerizing the dispersion medium component in the coating film of such a colloidal dispersion is not particularly limited, and the dispersion medium component can be obtained without losing the crystal structure formed in a self-organized manner in the coating film. A known method capable of polymerizing can be suitably employed, and examples thereof include a polymerization method by photopolymerization and a polymerization method by heating. In addition, when making it superpose | polymerize by heating, it is preferable to superpose | polymerize on about 80 degrees C or less temperature conditions from a viewpoint of preventing that a crystal structure lose | disappears by heating.

  In addition, among such polymerization methods of the dispersion medium component, the dispersion medium component can be polymerized more efficiently while maintaining the regular arrangement structure of the colloidal particles formed in the coating film without heating. From the viewpoint, it is preferable to employ a method of polymerizing by irradiating electromagnetic waves (such as ultraviolet light and electron beam). In addition, when a photopolymerizable monomer or the like is contained in the colloidal dispersion, it is preferable to employ a photopolymerization method in which a dispersion medium component is polymerized by irradiating light. Further, in the case of adopting a photopolymerization method as a polymerization method of such a dispersion medium component, a solution containing a photopolymerization initiator is used as the colloidal dispersion from the viewpoint of performing a polymerization reaction more efficiently. It is preferable.

  In such photopolymerization, it is preferable to perform the polymerization under a temperature condition of about 0 to 40 ° C. from the viewpoint of polymerization while maintaining the three-dimensional ordered arrangement structure of the colloidal particles in the colloidal crystal more sufficiently. Furthermore, in such photopolymerization, it is preferable to irradiate the coating film with light in an inert gas atmosphere (for example, a nitrogen gas atmosphere) from the viewpoint of suppressing inhibition of the radical polymerization reaction of the monomer by oxygen. . In addition, the light to be irradiated during such photopolymerization is not particularly limited, and light having a suitable wavelength may be adopted according to the type of monomer or photopolymerization initiator, for example, ultraviolet light is adopted. May be.

  In addition, the dispersion medium component in the coating film is polymerized in this manner to fix the colloidal crystals with the polymer, whereby the shape of the region having the first contact angle and the region having the second contact angle are obtained. A colloidal crystal film having irregularities formed according to the shape is obtained. That is, as described above, the wettability with respect to the colloidal dispersion is different between the region having the first contact angle and the region having the second contact angle. The coating thickness of the colloidal dispersion liquid is more easily spread by wetting, whereas the thickness of the coating film is smaller in the area having a larger angle, and the colloidal dispersion liquid is harder to spread and spread in the area having a smaller angle. When a colloidal crystal film fixed with a polymer is produced using a substrate having a region having a first contact angle and a region having a second contact angle, the first contact The thickness of the film formed on the area having the corners and the thickness of the film formed on the area having the second contact angle are different. Irregularities corresponding to is formed, it is possible to patterning of the colloidal crystal film.

  In the colloidal crystal film thus obtained, the reflectance in the reflection spectrum exceeds 30% (more preferably 40%) and the half width is 50 nm (more preferably 40 nm) or less in at least a part of the region. It is preferable that a colloidal crystal structure having a reflection peak is confirmed. In the region where the reflectance is less than the lower limit, a highly design colloidal crystal structure having sufficient color development tends not to be formed. Moreover, when the half width exceeds the upper limit, the high saturation, which is one of the structural colors of the colloidal crystals, tends to be impaired. As a method for measuring the reflection spectrum of the colloidal crystal film mentioned here, a multi-channel spectrometer (trade name “Multi-channel spectrometer Fastvert S-2650” manufactured by Soma Optical Co., Ltd.) is used, and a substrate is formed with a coaxial optical fiber. A method of measuring a reflection spectrum in a direction perpendicular to the surface is adopted. In the present invention, the vertical axis of the reflection spectrum is obtained by dividing the measured reflection spectrum of the colloidal crystal film by the reference spectrum using the reflection spectrum of the aluminum vapor deposition film deposited on the substrate as the reference spectrum. The reflectance spectrum graph is obtained by plotting this reflectance.

  Moreover, it is preferable that the colloidal crystal film having such irregularities has a region having an average film thickness in the range of 25 to 45 μm and a region having an average film thickness outside the range. In the region where the average film thickness is in the range of 25 to 45 μm, the colloidal particles in the colloidal dispersion liquid are easily rearranged in a self-organized manner, and are easily rearranged with the crystal orientation aligned in the film thickness direction. Therefore, the orientation becomes better, the coating film in the region can be made into a film having a more uniform and higher reflectance, and the design property of the colloidal crystal film in the region is made higher. I can. Further, in a region having a film thickness in the range of 25 to 45 μm, there is a reflection peak in which the reflectance exceeds 30% (more preferably 40%) and the half width is 50 nm (more preferably 40 nm) or less in the reflection spectrum. A confirmed colloidal crystal structure is more easily formed. It should be noted that in a region where the film thickness is less than 25 μm, the reflectance tends to be lower than that in a region where the average film thickness is in the range of 25 to 45 μm. On the other hand, in the region where the average film thickness exceeds 45 μm, the orientation is disturbed, so that there is a tendency that a uniform color developing film is not obtained. Therefore, the colloidal crystal film has a region having an average film thickness in the range of 25 to 45 μm and a region having a film thickness outside the above range, so that color development can be performed according to the film thickness of the region. Different patterns can be generated such as letters, pictures and designs.

  In the present invention, the average film thickness of the polymerized film (colloidal crystal film) is determined by the method described below. That is, first, after the formed colloidal crystal film is damaged with a cutter knife, the surface of the colloidal crystal film and the surface of the base material are formed using an optical microscope (for example, trade name “VF-7500” manufactured by Keyence Corporation). The position of the objective lens when focusing is read from the scale built into the microscope. Note that the position of the objective lens is read in units of 1 μm. Next, the difference between the reading values is obtained. Thereby, the film thickness of the colloidal crystal film at the measurement location is obtained. In the present invention, the thickness of the colloidal crystal film is measured at any five or more measurement points by such a measuring method, and the average value of these is calculated to obtain the average film thickness of the colloidal crystal film.

  Thus, in the present invention, the colloidal crystal film can be easily patterned by performing the above-described steps (A) to (E). Further, the pattern shape formed by such patterning changes due to the shape of the region having the first contact angle and the shape of the region having the second contact angle on the substrate surface after the surface treatment. Therefore, the shape of the region in which the contact angle is changed in the range of 0 ° to 40 ° by the surface treatment can be an arbitrary design, and a desired design can be patterned. Therefore, in the present invention, a colloidal crystal film whose surface is patterned in an arbitrary design can be efficiently obtained by a simple method.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

  In addition, the “contact angle” of the substrate (black painted steel plate or resin substrate) described in each of the following test examples, examples and comparative examples is JIS R3257 “Method for testing the wettability of the substrate glass surface”. It is a value measured by a conforming measuring method, using a product name “CA-A” manufactured by Kyowa Interface Chemical Co., Ltd. as a measuring device, and using 2 mL droplets (dispersion liquid) under a temperature condition of 23 ° C. About 15 seconds after dropping the droplet, the angle formed by the straight line connecting the point of contact between the substrate surface, the droplet and air, and the apex of the droplet with the substrate surface is read. It is a value measured by doubling.

(Synthesis Example 1)
First, a polyethylene glycol diacrylate monomer (trade name “NK Ester A-200” manufactured by Nakamura Chemical Co., Ltd.) and a polyethylene glycol monoacrylate monomer (trade name “NK Ester AM-30G manufactured by Shin Nakamura Chemical Co., Ltd.) Mixing was performed at a weight ratio of 8: 2, thereby preparing a dispersion medium composed of monomers. Next, silica particles (average particle diameter 200 nm, monodispersity: 5%) synthesized by the Stober method are added to the dispersion medium so that the content is 27% by volume, and the room temperature (25 ° C.) is added. Under the conditions, ultrasonic waves (45 kHz) were applied for 3 hours for dispersion to obtain a colloidal dispersion liquid in which colloidal particles (silica particles) were uniformly dispersed in the monomer. Then, 1% by weight of a photopolymerization initiator (trade name “Darocur 1173” manufactured by Ciba Specialty Chemicals) was added to the colloidal dispersion liquid thus obtained.

In the colloidal dispersion obtained as described above, an iris color was observed. Further, when a reflection spectrum was measured with respect to such a colloid dispersion using a trade name “Multichannel Spectrometer Fastvert” manufactured by Soma Optics, a reflection peak was observed, and the colloidal crystal was found in the colloid dispersion. It was confirmed that it was formed. The viscosity of the colloidal dispersion thus obtained was measured using a cone plate having a diameter of 25 mm and a cone angle of 0.1 rad using a “fluid spectrometer ARES” manufactured by Rheometrics Scientific. 25 ± 0.1 ° C., shear rate: was measured under the conditions of 1000 s ^-1, the viscosity of such a colloidal dispersion was 33 mPa · s.

(Test Example 1)
First, a black coated steel sheet was prepared by applying black solid coating (manufactured by Kansai Paint) on the intermediate coating. Next, after washing the black-coated steel sheet with a neutral detergent, the contact angle of the surface with respect to the colloidal dispersion obtained in Synthesis Example 1 is measured using the trade name “Kyowa Interface Science Co., Ltd.” as described above. It was measured using “CA-A”. As a result of such measurement, it was confirmed that the contact angle of the surface of the black-coated steel sheet with the colloidal dispersion was 29 °.

  Next, the black-coated steel sheet is subjected to UV ozone treatment using an optical surface treatment apparatus (trade name “PL16-110” manufactured by Sen Special Light Source Co., Ltd.). The relationship between the contact angle of the surface and the colloidal dispersion liquid (change in contact angle with the treatment time) was measured. At this time, UV was irradiated in an oxygen atmosphere so that the distance between the surface of the black-coated steel sheet and the lamp was 5 cm. The contact angle was measured 30 minutes after the UV ozone treatment. A graph showing the relationship between the treatment time by the UV ozone treatment and the contact angle of the surface of the black-coated steel sheet with the colloidal dispersion is shown in FIG.

  As is clear from the results shown in FIG. 1, in the black coated steel sheet, the contact angle with the colloidal dispersion on the surface can be 10 ° by UV ozone treatment for 10 minutes, and the UV ozone treatment for 15 minutes or more. Thus, it was confirmed that the contact angle of the surface with respect to the colloidal dispersion can be set to 5 ° to 6 °.

(Test Example 2)
A resin substrate was prepared by applying a black primer (Kansai Paint Retan PG60) to an ABS resin (acrylonitrile butyleneene styrene copolymer).

  Next, in the same manner as in Test Example 1 except that the resin substrate was used instead of the black-coated steel sheet, the treatment time by UV ozone treatment and the colloidal dispersion obtained in Synthesis Example 1 of the surface of the resin substrate were compared. The relationship with contact angle (change in contact angle with processing time) was measured. A graph showing the relationship between the treatment time by UV ozone treatment and the contact angle of the surface of the resin substrate with the colloidal dispersion is shown in FIG. In addition, the contact angle with respect to the colloid dispersion liquid on the surface of such a resin substrate was 13 °.

  As is apparent from the results shown in FIG. 2, the contact angle with respect to the colloidal dispersion once increased to 30 ° by the UV ozone treatment for 1 minute, and then the contact angle with respect to the colloidal dispersion was increased to 18 ° by the UV ozone treatment for 3 minutes. It was confirmed that the contact angle with respect to the colloidal dispersion can be reduced to 5 ° by UV ozone treatment for 5 minutes.

(Example 1)
A colloidal crystal film was produced using the colloidal dispersion obtained in Synthesis Example 1. That is, first, an untreated black painted steel plate (initial contact angle 29 °) similar to that used in Test Example 1 was prepared, and an optical surface treatment apparatus (manufactured by Sen Special Light Source Co., Ltd.) was applied to the black coated steel plate. The product is contacted with the colloidal dispersion by applying UV ozone treatment for 10 minutes in an oxygen atmosphere while maintaining a distance of 5 cm between the surface of the black-coated steel sheet and the lamp using a trade name “PL16-110”). A substrate having a surface with an angle of 10 ° was prepared. Next, a mask shaped like a dolphin and a mask shaped like a kingfisher are placed on the surface of the base material (the mask is made of cardboard that does not transmit light), so that light does not strike the part where the mask is placed. The UV ozone treatment was applied to the substrate for 10 minutes. After the UV ozone treatment, the contact angle with respect to the colloidal dispersion obtained in Synthesis Example 1 of the substrate was measured after 30 minutes. The contact angle was 5 ° in the region where the mask was not placed at 10 °.

  Next, the colloidal dispersion obtained in Synthesis Example 1 was prepared, and this was spray-coated on the surface of the substrate using an air spray gun to form a coating film. In such spray coating, the film thickness of the coating film was set to 30 μm (set film thickness: 30 μm).

  After forming a coating film by spray coating in this way, the substrate on which the coating film has been formed is conveyed into a glove box and irradiated with light from a high-pressure mercury lamp in a nitrogen atmosphere for 1 minute. The monomer in the film was photopolymerized. As a result, a colloidal crystal film fixed on the substrate with a polymer was produced.

  A photograph of the colloidal crystal film (thin film) thus obtained is shown in FIG. FIG. 4 shows a photograph of the colloidal crystal film (thin film) taken from an angle different from that in FIG. As is clear from the photographs shown in FIGS. 3 to 4, it was confirmed that the shape of dolphins and kingfishers, which are mask shapes, clearly appear in the obtained colloidal crystal film.

  In addition, the colloidal crystal film (thin film) shown in FIGS. 3 to 4 is formed on the area where the kingfisher pattern appears and the area outside the pattern (the area on the surface of the substrate that was not masked). And the reflection spectrum was measured. As a method for measuring such a reflection spectrum, a multi-channel spectrometer (trade name “S-2650” manufactured by Soma Optical Co., Ltd.) is used, and the diameter of each region is measured from the vertical direction with a coaxial optical fiber. A method of measuring the reflection spectrum by irradiating white light with an irradiation shape of 10 mm was adopted. The results are shown in FIG.

  As is clear from the results shown in FIG. 5, in the region where the kingfisher pattern appears (the film portion formed on the region where the mask was placed during the UV ozone treatment), the reflection peak intensity ( (Reflectance) exceeded 30%. On the other hand, the reflection peak intensity in the reflection spectrum was 21% in the region outside the above-mentioned kingfisher pattern (the peripheral part of the kingfisher pattern and other than the dolphin pattern part). From these results, it was confirmed that the obtained film was a colloidal crystal film, and the state of the regular arrangement of colloidal particles in the area where the kingfisher pattern appeared and the outer area (peripheral part) It was found that the structural coloration differs depending on the region.

  Next, regarding the colloidal crystal film thus obtained, the thickness of the region where the dolphin pattern and the kingfisher pattern appeared was measured using the following method. That is, first, each region was scratched using a cutter knife. Next, using an optical microscope (Keyence VF-7500 type), focus on the surface of the colloidal crystal film and the surface of the substrate that appears as a result of scratching, and position the objective lens at that time. Each reading was taken from the scale built into the microscope. And the difference of the measured reading value was calculated, and the film thickness of the colloidal crystal film was calculated | required by this. When measuring the film thickness, the position of the objective lens was read in units of 1 μm. Further, such measurement was performed at each of six measurement points in the region where the dolphin pattern appeared and the region where the kingfisher pattern appeared.

  As a result of such measurement, the film thickness of the area where the dolphin pattern appeared and the area where the kingfisher pattern appeared were 36 ± 2 μm (average film thickness 36 μm), respectively. Similarly, when the film thickness was measured at 10 measurement points in the area (peripheral part) where these patterns were not formed, the film thickness in the peripheral part was 23 ± 3 μm (average film thickness 23 μm). Met.

  From these results, according to the present invention (Example 1), the resulting colloidal crystal film is derived from the shape of the mask in a simple process by simply changing the time of UV ozone treatment for the substrate using the mask. It was found that the pattern can be made uneven, and the color development of the colloidal crystal can be made different, and it was confirmed that a colloidal crystal film patterned with a desired design can be efficiently produced.

(Example 2)
A colloidal crystal film was produced using the colloidal dispersion obtained in Synthesis Example 1. That is, first, except that the time of UV ozone treatment for untreated black-coated steel sheets was changed from 10 minutes to 5 minutes and the time of UV ozone treatment after placing the mask was changed from 10 minutes to 15 minutes. A base material was prepared in the same manner as the base material preparation step employed in Example 1. The area of the substrate surface thus obtained where the mask was placed had a contact angle of 24 °, and the area where no mask was placed had a contact angle of 5 °. Next, a colloidal crystal film was produced in the same manner as in Example 1 except that the base material thus obtained was used and the set film thickness at the time of spray coating was 40 μm.

  In the colloidal crystal film thus obtained, the film portion formed on the area where the mask was not placed showed a uniform color, and when the substrate was viewed from directly above, it was red. On the other hand, the film portion formed on the area where the mask was placed was a film having a dull color such as being cloudy. Thus, in the obtained colloidal crystal film, it was confirmed that the pattern of a dolphin and a kingfisher was raised by the difference in coloring. Further, when the reflection spectrum of the outer region (peripheral part) of the dolphin pattern and kingfisher pattern of such a colloidal crystal film was measured in the same manner as in Example 1, a reflection peak exceeding 30% was confirmed. It was confirmed that a colloidal crystal film having a sufficiently high reflectance was obtained. On the other hand, in the region where the dolphin pattern and kingfisher pattern were formed, the reflection peak intensity in the reflection spectrum was less than 30%.

  Moreover, when the film thickness of the area | region where the dolphin pattern appeared and the area | region outside the kingfisher pattern was measured similarly to Example 1 (measurement point: 6 places), film thickness was 38 +/- 3micrometer (average film thickness) 38 μm). Similarly, when the film thickness of the region (peripheral part) where the pattern was formed was measured (measurement point: 10 points), the film thickness was 48 ± 3 μm (average film thickness 48 μm).

(Example 3)
A colloidal crystal film was produced using the colloidal dispersion obtained in Synthesis Example 1. That is, first, a hole is formed in a cardboard in the same shape as the mask shape shaped like a dolphin used in Example 1 and the shape of a mask shaped like a kingfisher used in Example 1, and a hole of dolphin shape and kingfisher shape A mask made of cardboard with an opening was prepared. Next, an untreated black-coated steel plate (initial contact angle 29 °) similar to that used in Test Example 1 was prepared, and after placing the mask on the black-coated steel plate, an optical surface treatment apparatus ( Using a special light source manufactured by Sen Special Light Source Co., Ltd., trade name “PL16-110”), the surface of the black-coated steel sheet and the lamp were subjected to UV ozone treatment for 10 minutes to irradiate UV in an oxygen atmosphere while maintaining a distance of 5 cm. Thereafter, the mask was removed, and UV ozone treatment was further applied for 10 minutes to prepare a substrate. After the UV ozone treatment, the contact angle with respect to the colloidal dispersion obtained in Synthesis Example 1 of the substrate was measured after 30 minutes. The contact angle was 5 ° in the region where the mask was not placed (the portion where the hole was opened). Next, a colloidal crystal film was produced in the same manner as in Example 1 except that the substrate thus obtained was used.

  In the colloidal crystal film thus obtained, when the substrate is viewed from directly above, there are portions where the coloration is slow in the shape of dolphins and kingfishers, and a region showing a uniform red coloration is formed in the periphery. The pattern of dolphins and kingfishers emerged due to the difference in color. In addition, when such a colloidal crystal film was observed from a slight angle, a color with a three-dimensional appearance was observed, in which the color was generally green and the dolphin and kingfisher-shaped parts were slightly sunk. . Further, in the same manner as in Example 1, when the reflection spectrum of the outer region (peripheral part) of the dolphin pattern and kingfisher pattern of such a colloidal crystal film was measured, a reflection peak intensity exceeding 30% was confirmed. It was confirmed that a colloidal crystal film having a sufficiently high reflectance was obtained. On the other hand, in the area where the dolphin pattern and kingfisher pattern were formed (the film part formed on the area of the base material where the mask hole was opened (contact angle is 5 °)), the reflection peak intensity was It was less than 30%.

  Further, in the same manner as in Example 1, when the film thickness of the area where the dolphin pattern appeared and the area where the kingfisher pattern appeared were measured (measuring points: 6 points), the film thickness was 22 ± 3 μm (average film). The thickness was 22 μm). Similarly, when the film thickness of the region (peripheral part) where these patterns are not formed is measured (measurement point: 10 points), the film thickness of the peripheral part is 33 ± 3 μm (average film thickness 33 μm). there were.

Example 4
A resin substrate similar to that used in Test Example 2 was used instead of the black coated steel plate, the UV ozone treatment time for the untreated resin substrate was 3 minutes, and the UV ozone treatment time after placing the mask was 3 minutes. A substrate was prepared in the same manner as in Example 1 except that the minute was used. Thus, the area | region which put the mask of the surface of the base material obtained in this way was a contact angle of 18 degrees, respectively, and the area | region where the mask was not put was a contact angle of 5 degrees. Next, a colloidal crystal film was produced in the same manner as in Example 1 except that the substrate thus obtained was used.

  In the colloidal crystal film thus obtained, the film portion formed on the area where the mask was not placed showed a uniform color, and when the substrate was viewed from directly above, it was red. On the other hand, the film portion formed on the area where the mask was placed was a film having a dull color such as being cloudy. Thus, in the obtained colloidal crystal film, it was confirmed that the pattern of a dolphin and a kingfisher was raised by the difference in coloring. Further, in the same manner as in Example 1, the reflection spectrum of the region where the dolphin pattern and the kingfisher pattern of the colloidal crystal film appear (the film part formed on the region where the mask of the base material is placed) is obtained. When measured, a reflection peak exceeding 30% was confirmed, and it was confirmed that a colloidal crystal film having a sufficiently high reflectance was obtained. On the other hand, the reflection peak intensity was less than 30% in the outer region (peripheral portion) of the pattern.

  Moreover, when the film thickness of the area where the dolphin pattern appeared and the area where the kingfisher pattern appeared was measured in the same manner as in Example 1 (measurement points: 6 points), the film thickness was 34 ± 3 μm (average film). The thickness was 34 μm). Similarly, when the film thickness of the region (peripheral part) where these patterns are not formed is measured (measuring points: 10 points), the film thickness of the peripheral part is 23 ± 3 μm (average film thickness 23 μm). there were.

(Effect 5)
A colloidal crystal film was produced using the colloidal dispersion obtained in Synthesis Example 1. That is, first, an untreated black painted steel plate (initial contact angle 29 °) similar to that used in Test Example 1 was prepared, and an optical surface treatment apparatus (manufactured by Sen Special Light Source Co., Ltd.) was applied to the black coated steel plate. The product was contacted with the colloidal dispersion by applying a UV ozone treatment for 15 minutes in an oxygen atmosphere while maintaining a distance of 5 cm between the surface of the black-coated steel sheet and the lamp using a trade name “PL16-110”). A substrate having a surface with an angle of 5 ° was prepared. Next, a mask made of cardboard with holes in the shape of dolphins and kingfishers similar to the mask used in Example 3 is prepared, and the mask is placed on the substrate and impregnated with n-propyl alcohol. The mask mold part (the dolphin shape and the kingfisher-shaped hole part) on the surface of the substrate was wiped with a bencott. After the treatment with n-propyl alcohol, the contact angle with respect to the colloidal dispersion obtained in Synthesis Example 1 of the base material was measured after 30 minutes. The area where the mask was not wiped was 5 °, and the area where the mask was not placed (the area wiped with Bencott) was 24 °. Next, a colloidal crystal film was produced in the same manner as in Example 1 except that the substrate thus obtained was used.

  In the colloidal crystal film thus obtained, when the substrate is viewed from directly above, there are portions where the coloration is slow in the shape of dolphins and kingfishers, and a region showing a uniform red coloration is formed in the periphery. It was confirmed that the pattern of dolphins and kingfishers emerged due to the difference in color. Moreover, when such a colloidal crystal film is observed from a slight angle, the whole color develops green, and the dolphin and kingfisher-shaped parts appear to have submerged slightly from the color of the color. A pattern with was observed. Further, in the obtained colloidal crystal film, when the reflection spectrum of the outer region (peripheral part) of the dolphin pattern and kingfisher pattern of such a colloidal crystal film was measured in the same manner as in Example 1, 30 The reflection peak intensity exceeding% was confirmed, and it was confirmed that a colloidal crystal film having a sufficiently high reflectance was obtained. On the other hand, the reflection peak intensity was less than 30% in a region where a dolphin pattern and a kingfisher pattern were formed (a film portion on a region wiped with a base material Bencot).

  Further, in the same manner as in Example 1, when the film thickness of the area where the dolphin pattern appeared and the area where the kingfisher pattern appeared were measured (measuring points: 6 points), the film thickness was 50 ± 3 μm (average film). The thickness was 50 μm). Similarly, when the film thickness of the region (peripheral part) where these patterns were not formed was measured (measuring points: 10 locations), the film thickness was 39 ± 3 μm (average film thickness 39 μm).

(Example 6)
A colloidal crystal film was produced using the colloidal dispersion obtained in Synthesis Example 1. That is, first, except that the time of UV ozone treatment for untreated black-coated steel sheet was changed from 10 minutes to 8 minutes and the time of UV ozone treatment after placing the mask was changed from 10 minutes to 5 minutes. A base material was prepared in the same manner as the base material preparation step employed in Example 1. The regions where the mask was placed on the surface of the substrate thus obtained had a contact angle of 12 °, and the regions where no mask was placed had a contact angle of 8 °. Next, a colloidal crystal film was produced in the same manner as in Example 1 except that the base material thus obtained was used and the set film thickness at the time of spray coating was changed to 50 μm.

  In the colloidal crystal film thus obtained, dolphin and kingfisher patterns were confirmed by their outlines. In addition, when the reflection spectrum of such a colloidal crystal film was measured in the same manner as in Example 1, a reflection peak was confirmed, and it was confirmed that a colloidal crystal was formed. The reflection peak intensity in the reflection spectrum was less than 30% in both the dolphin and kingfisher pattern portions (film portions formed on the region where the mask of the base material was placed) and the outer peripheral portions thereof.

  Further, in the same manner as in Example 1, when the film thickness of the area where the dolphin pattern appeared and the area where the kingfisher pattern appeared were measured (measuring points: 6 points), the film thickness was 50 ± 3 μm (average film). The thickness was 50 μm). Similarly, when the film thickness of the region (peripheral part) where these patterns were not formed was measured (measurement point: 10 points), the film thickness was 47 ± 3 μm (average film thickness 47 μm).

(Comparative Example 1)
A colloidal crystal film was produced using the colloidal dispersion obtained in Synthesis Example 1. That is, first, except that the time of UV ozone treatment for untreated black-coated steel sheet was changed from 10 minutes to 15 minutes and the time of UV ozone treatment after placing the mask was changed from 10 minutes to 5 minutes. A substrate was prepared in the same manner as in Example 1. The region on the surface of the substrate thus obtained where the mask was placed had a contact angle of 5 °, and the region where no mask was placed had a contact angle of 5 °. That is, the substrate thus obtained had a contact angle of 5 ° with respect to the colloidal dispersion in all regions of the surface. Next, a colloidal crystal film was produced in the same manner as in Example 1 except that the base material thus obtained was used and the set film thickness at the time of spray coating was 40 μm.

  The colloidal crystal film thus obtained showed a uniform structural color and did not show a mask pattern. Further, when the film thickness of the colloidal crystal film thus obtained was measured in the same manner as in Example 1, the film formed on the region where the substrate mask was placed was also covered with the substrate mask. The thickness of the film formed on the unplaced region was 37 ± 3 μm (average film thickness 37 μm). From these results, it was found that patterning cannot be performed when the difference between the first contact angle and the second contact angle is 0 ° even if the time of the UV ozone treatment is different.

(Comparative Example 2)
A colloidal crystal film was produced using the colloidal dispersion obtained in Synthesis Example 1. That is, first, only a 15-minute UV ozone treatment was applied to an untreated black-coated steel sheet. The black-coated steel sheet treated with UV ozone in this way had a contact angle of 5 ° with respect to the colloidal dispersion in all areas of the surface. Next, a fluorine coating agent (trade name “G-600”, manufactured by Shin-Showa Co., Ltd.) is partially applied thinly to the black painted steel plate with a cotton swab and allowed to dry naturally for about 30 minutes. Got. Thus, after apply | coating a fluorine coating agent, when 30 minutes passed, the contact angle with respect to the said colloid dispersion liquid of the area | region which applied the fluorine coating agent was measured, and the contact angle was 65 degrees. In addition, the contact angle in other regions remained at 5 °. Next, a colloidal crystal film was produced in the same manner as in Example 1 except that the base material thus obtained was used and the set film thickness at the time of spray coating was 40 μm.

  In the colloidal crystal film thus obtained, the portion where the fluorine coating agent was not applied showed a uniform color and was red when the substrate was viewed from directly above, but the fluorine coating agent was applied. In the region, dome-shaped lumps having a diameter of 1 mm or less gathered in the form of droplets, and it was confirmed that a continuous film was not formed. From these results, it was found that when a substrate having a region with a contact angle of 65 ° with respect to the colloidal dispersion was used, the colloidal dispersion did not sufficiently wet and spread, and a continuous film could not be formed.

  From the above results, regions having different contact angles with respect to the colloidal dispersion are partially formed in the range of 0 ° to 40 °, and the difference in contact angles between the regions having different contact angles is 4 ° or more. By using the base material and the colloid dispersion liquid, the colloid dispersion liquid is applied to the base material, and the dispersion medium is cured (polymerized), thereby forming irregularities according to the shapes of the regions having different contact angles. It was confirmed that the colloidal crystal film thus obtained can be obtained, and the colloidal crystal film can be patterned. Further, from the results shown in Examples 1 to 5, it was found that in the obtained colloidal crystal film, the peak intensity of the reflection spectrum is different between the concave portion and the convex portion. Furthermore, when the intensity | strength of the reflection spectrum of at least one area | region is 30% or more from the result shown in Examples 1-6 (Examples 1-5), color development becomes better in the area | region, and it is more designable. It was also found to be a rich colloidal crystal film.

  As described above, according to the present invention, there is provided a method for producing a patterned colloidal crystal film, which can efficiently and reliably produce a colloidal crystal film whose surface is patterned in an arbitrary design. It becomes possible. Such a method for producing a patterned colloidal crystal according to the present invention is particularly useful as a method for producing a structural color material because it can provide a colloidal crystal film having excellent design.

Claims (5)

A dispersion medium component containing at least one selected from the group consisting of a monomer and a polymer, an average particle diameter in the range of 0.01 to 10 μm, and the following formula (1):
[Monodispersity (unit:%)] = ([standard deviation of particle size] / [average particle size]) × 100 (1)
And a colloidal dispersion in which the colloidal particles are dispersed in the dispersion medium component in a three-dimensional regular array state having a reflection peak in a reflection spectrum. The process of preparing
Preparing a substrate having a first contact angle with a surface in the range of 0 ° to 40 ° with respect to the colloidal dispersion;
A surface treatment for changing a contact angle of the partial region of the surface of the base material to the colloidal dispersion in a range of 0 ° to 40 ° is applied to the base material, and the partial region after the surface treatment is applied. A region having a second contact angle at which an angle difference from the first contact angle is 4 ° or more;
Applying the colloidal dispersion to the substrate after the surface treatment to form a coating film;
The dispersion medium component in the coating film is polymerized to fix the colloidal crystals with the polymer, and irregularities are formed according to the shape of the region having the first contact angle and the region having the second contact angle. Obtaining a colloidal crystal film,
A method for producing a patterned colloidal crystal film, comprising:   The one of the first and second contact angles is in a range of 0 ° to 6 °, and the other angle is in a range of more than 6 ° and 40 ° or less. A method for producing the patterned colloidal crystal film as described.   3. The patterned colloid according to claim 1, wherein the colloidal crystal film has a region having an average film thickness in a range of 25 to 45 μm and a region having an average film thickness outside the range. A method for producing a crystal film. The colloidal dispersion liquid has a viscosity of 10 to 100 mPa · s measured at a shear rate of 1000 S ⁻¹ under a temperature condition of 25 ° C. ± 0.1 ° C. 5. The manufacturing method of the patterned colloidal crystal film as described in any one of Claims.   The patterning according to any one of claims 1 to 4, wherein in the step of forming the coating film, the colloidal dispersion is applied to the substrate after the surface treatment by spray coating. A method for producing a colloidal crystal film.