JP6142562B2 - Super water-repellent material manufacturing method and super water-repellent material - Google Patents

Description

  The present invention relates to a super water-repellent material provided with a film exhibiting super water repellency and a method for producing the same.

  Conventionally, water-repellent materials such as metal materials, ceramic materials, glass materials, resin materials, etc., are formed into a film to form not only water repellency but also antifouling properties, anti-fogging, etc. Functionality is added. The wettability of a solid surface depends not only on the chemical affinity of the surface but also on the geometric shape of the surface. Therefore, the formation of the water-repellent film is controlled not only by controlling the chemical properties of the surface but also by controlling the form such as providing a fine uneven structure or nanostructure. As a method for forming such a water-repellent film, the following are typically proposed and put into practical use (see, for example, Patent Document 1).

  (A) Decomposing organosilicon compounds such as tetramethylsilane (TMS), tetramethoxysilane (TMOS), and hexamethyldisiloxane (HMDSO) by generating plasma in a vacuum, and hydrophobic A technique for producing a water-repellent film by depositing particles having a methyl group on a substrate. (B) The surface of the base material is subjected to oxygen plasma treatment in a vacuum, thereby forming fine irregularities on the surface of the base material to make it hydrophilic, and then a self-organized unit consisting of an organosilicon compound having a hydrophobic functional group. A method of hydrophobizing by forming a molecular film (SAM film). (C) Hydrophobizing the surface of the substrate by irradiating it with vacuum ultraviolet light (VUV), and then forming a self-assembled monomolecular film (SAM film) made of an organosilicon compound having a hydrophobic functional group to make it hydrophobic Technique. (D) A method in which the surface of the substrate is hydrophilized by atmospheric pressure plasma treatment and then hydrophobized by forming a self-assembled monomolecular film (SAM film) made of an organosilicon compound having a hydrophobic functional group.

JP 2010-222703 A JP 2004-17591 A

  In the methods shown in the above (a) and (b), it is necessary to perform the hydration treatment in a vacuum chamber, so the size of the base material is limited and the equipment has to be expensive. It was. In addition, since all of the conventional methods shown in the above (a) to (d) express water repellency by hydrophobizing the surface of the base material and then hydrophobizing it, the work process is complicated and long. It was time consuming.

By the way, the inventors formed irregularities having a surface roughness in the range of 5 to 200 nm by dry etching on the surface of the polymer substrate, and then the film thickness was in the range of 1 to 150 nm by vapor phase method on the irregularities. It has been proposed to form a water-repellent layer that is an inner layer (see Patent Document 2). This water repellent layer is composed of an organic silicon material, an organic silicon fluoride material, or a polymer thereof, and has a hydrophobic group such as a methyl group in its molecular structure. For example, the contact angle with water is 70 degrees or more (for example, , About 140 degrees).
However, in such a water-repellent layer, so-called super-water-repellent property with a contact angle with water of 150 degrees or more has not been realized. Further, this water-repellent layer has low strength, and there remains a problem in the adhesion between the self-assembled monomolecular film constituting the water-repellent layer and the substrate.

  The present invention was created in view of the above problems, and a method for producing a super water-repellent material capable of forming a film that is transparent and exhibits super water repellency under an atmospheric pressure environment with high adhesion to the substrate, and An object of the present invention is to provide a super water repellent material in which a transparent super water repellent film is firmly bonded.

  In order to solve the above-described problems of the prior art, the present invention provides a method for producing a super water-repellent material. Such a production method includes generating ultrafine particle silica having an average particle diameter of 1 nm to 100 nm on the base material by generating plasma in an atmospheric pressure atmosphere into which the organosilicon compound is introduced with respect to the base material having a metallic surface. A particulate silica compound having an average particle size of 10 nm to 5000 nm is grown by depositing a compound and exposing the substrate on which the ultrafine silica compound is deposited to an atmosphere containing the organosilicon compound. And forming a film having a concavo-convex structure on the surface formed by bonding to each other.

  According to the study by the present inventors, the ultrafine silica compound obtained by thermally decomposing an organosilicon compound is randomly deposited on the substrate surface. Such disorderly deposition of ultrafine particles forms a large number of voids between which the liquid phase cannot enter. And the fine concavo-convex structure formed by such ultrafine particles and voids can express super water repellency of 150 degrees or more as it is. However, the ultrafine silica particles formed in this way are not firmly bonded to each other and can exist in an extremely unstable state. Therefore, the film strength and the adhesion between the film and the substrate are not fully satisfactory.

  In the production method of the present invention, the ultrafine silica compound is appropriately grown by supplying an organic silicon compound to the deposit of the ultrafine silica compound by a vapor phase method, and grown at the same time. A particulate silica compound is reliably bonded to form a film. In addition, such grain growth reduces the gap between adjacent granular silica compounds in a region close to the substrate, and can be a relatively dense and high-strength film. Furthermore, by using a material having a metallic surface as the base material, it is possible to realize a strong bond between the film-like body made of the granular silica compound and the base material. This makes it possible to produce a super water-repellent material having a super water-repellent film on the substrate with good adhesion.

Although not defined academically, the degree of water repellency is generally distinguished by the contact angle with water (a predetermined volume of water droplets) on the solid surface. That is, the water repellency is distinguished when the contact angle θ with water is 90 degrees or more and less than 120 degrees, the water repellency is 120 degrees or more and less than 150 degrees, and the water repellency is distinguished when the contact angle θ is 150 degrees or more. In this specification, “super water-repellent” refers to a state where the contact angle θ with water is 150 degrees or more.
The “ultrafine particle silica compound” and the “granular silica compound” are mainly composed of silica (SiO ₂ ), and the silica Si—O—Si network is terminated by an organic functional group, so that C, The compound is referred to as a “compound” in that it can contain different elements such as H and F.
Furthermore, “ultra-fine silica compound is deposited“ disordered ”represents a state in which no geometric order is observed in the deposition mode of the ultra-fine silica compound. For example, this does not prevent the deposition mechanism of the ultrafine silica compound from being based on chemical or thermodynamic order.

In a preferred embodiment of the production method disclosed herein, the substrate on which the ultrafine silica compound is deposited is exposed to an atmosphere containing the organosilicon compound at a temperature of 200 ° C. or higher.
In such a production method, thermal energy is applied during the growth of the ultrafine silica compound to promote grain growth, and it is possible to reliably bond the grains, for example, by forming a neck. Further, by heating to a temperature of 200 ° C. or higher, the crystallinity of the formed silica can be increased, and a film having high mechanical strength (for example, hardness) can be formed.

In a preferred embodiment of the production method disclosed herein, the method further includes a step of forming a metal film on a base material to prepare a base material having the metallic surface, wherein the metal film is made of copper (Cu), It is composed of at least one metal selected from the group consisting of nickel (Ni), aluminum (Al), silicon (Si), silver (Ag), zinc (Zn) and iron (Fe) or an alloy thereof. It is said.
According to this structure, it can use as a base material which has a metallic surface of this invention by providing a metal film in the surface aiming at provision of super water repellency with respect to the base material which consists of arbitrary raw materials. That is, as a base material, if the surface is a metallic surface, it will not limit about the raw material of another site | part.

In a preferred embodiment of the manufacturing method disclosed herein, the metal film is formed to a thickness of 1 μm or less.
By forming the metal film with a thickness of 1 μm or less, typically about 10 nm to 500 nm, more preferably about 10 nm to 300 nm, the metal film is transparent (transparent to visible light, the same shall apply hereinafter). Can do. In addition, since the film | membrane which consists of said granular silica compound is essentially transparent, when a transparent material is used as a base material, the whole super-water-repellent material can be manufactured as a transparent thing, for example.

In a preferred embodiment of the production method disclosed herein, glass or a resin material is used as the base material.
The manufacturing method of the present invention does not require heat treatment at a high temperature (for example, about 350 ° C. or higher), for example. Therefore, for example, a super water-repellent material based on various materials that are altered or melted at a high temperature of about 350 ° C. or higher can be manufactured. Further, as described above, the entire super water-repellent material can be produced as a transparent material. From these characteristics, the production method of the present invention is preferable because the advantages can be exhibited to the maximum when a glass material or a resin material is used as the base material.
The invention disclosed herein also provides a super water-repellent material manufactured by any one of the manufacturing methods described above.

In order to solve the above problems from other aspects, the invention disclosed herein provides a super water-repellent material. Such a super-water-repellent material is a film having a concavo-convex structure on the surface, wherein a granular silica compound having an average particle size of 10 nm to 5000 nm formed by decomposing an organosilicon compound is bonded to a substrate having a metallic surface. It is characterized by being equipped.
Since the super-water-repellent material of the present invention is formed by the connection of the granular silica compound, in addition to the unevenness formed by the deposited state of the granular silica compound, the unevenness formed by the adjacent granular silica compound An extremely complicated uneven structure is formed. As a result, the surface area is significantly enlarged, the actual free surface energy is higher than that of the plane, and a wettable surface is formed more easily. Due to such shape characteristics, the super water-repellent material of the present invention can realize a surface with high water repellency.

As a preferred embodiment of the super water-repellent material, the contact angle of water on the surface of the film is 150 degrees or more.
Due to the extremely complicated concavo-convex structure as described above, the film made of the granular silica compound can exhibit extremely high water repellency, that is, super water repellency. Thus, for example, a transparent material exhibiting super water repellency is provided.

As a preferred embodiment of the super water-repellent material, a reaction layer formed by a reaction between the film and the metallic surface is formed at an interface between the film and the metallic surface. .
In such a super water-repellent material, the presence of this reaction layer chemically bonds the metal element constituting the metallic surface and the silicon constituting the granular silica compound. This provides a super water-repellent material in which a film made of a granular silica compound and a substrate surface are firmly bonded (fixed).

As a preferred embodiment of the super water-repellent material, a critical load when the film is peeled from the substrate based on a scratch test is 50 mN or more.
As described above, the super water-repellent material has a high film adhesion because the film made of the granular silica compound and the substrate surface are chemically bonded. For example, when a scratch test based on JIS R-3255 (a thin film adhesion test method using glass as a substrate) is used as an index, it is realized as having a high film adhesion with a critical load of 50 mN or more.

As a preferred embodiment of the super water-repellent material, the metallic surface has a thickness of 1 μm or less.
The metal film can be transparent when it has a thickness of 1 μm or less, typically about 10 nm to 500 nm, more preferably about 10 nm to 300 nm. In addition, since the film | membrane which consists of said granular silica compound is essentially transparent, when a transparent material is used as a base material, the whole super-water-repellent material can be implement | achieved as a transparent thing, for example.

As a preferred embodiment of the super water-repellent material, the base material is glass or resin, and the metallic surface is copper (Cu), nickel (Ni), aluminum (Al), silicon (Si), silver (Ag), zinc (Zn), and at least one metal selected from the group consisting of steel and alloys thereof.
Such a metallic surface is preferably constituted so as to contain a metal element that can be chemically bonded to silicon constituting a film made of a granular silica compound. Therefore, a water-repellent material excellent in mechanical properties such as film adhesion is provided by forming the metal surface from a metal containing the above metal element or an alloy thereof.

It is the figure which illustrated the scanning electron microscope (SEM) image which observed the (a) cross section and (b) surface of the base material with which the ultrafine particle silica compound was deposited. It is the figure which illustrated the scanning electron microscope (SEM) image which observed the (a) cross section and (b) surface of the super-water-repellent material produced by making vapor phase growth temperature 240 degreeC. It is the figure which illustrated the scanning electron microscope (SEM) image which observed the (a) cross section and (b) surface of the super-water-repellent material produced by making vapor phase growth temperature 260 degreeC. It is the figure which illustrated the scanning electron microscope (SEM) image which observed the (a) cross section and (b) surface of the super-water-repellent material produced by making vapor phase growth temperature 270 degreeC. It is the figure which illustrated the scanning electron microscope (SEM) image which observed the (a) cross section of the super-water-repellent material produced by making vapor phase growth temperature 290 degreeC, and (b) the principal part enlarged view. It is the figure which illustrated the Fourier-transform infrared-spectroscopy (FT-IR) spectrum of the film | membrane which consists of the granular silica compound formed on different conditions. It is the figure which illustrated the critical load by the scratch test of the film | membrane which consists of the granular silica compound formed on different conditions. It is the figure which illustrated the hardness of the film | membrane which consists of the granular silica compound which made the metallic surface of a base material Cu or Ni, and was formed on different conditions. It is the figure which illustrated the SEM image which observed the (a) surface and (b) cross section of the film | membrane which consists of the granular silica compound which formed the metallic surface of the base material as Al. It is the figure which illustrated the SEM image which observed the (a) surface and (b) cross section of the film | membrane which consists of a granular silica compound which formed the metallic surface of the base material as Ni. Example of SEM observation of the surface of a film made of a granular silica compound in which the metallic surface of the substrate is formed as (a) Zn, (b) Cu, (c) Al, (d) Ag, (e) Si FIG. (A) SEM image and (b) partial enlargement of the surface of a film made of granular silica compound, in which the metallic surface of the base material is SUS steel and vapor phase growth is performed at 250 ° C. for 1 hour. It is the figure which illustrated the figure. (A) SEM image and (b) partial enlargement of the surface of the film made of granular silica compound, in which the metallic surface of the base material was SUS steel and vapor phase growth was performed at 270 ° C. for 1 hour. It is the figure which illustrated the figure.

Hereinafter, the super water-repellent material of the present invention and the production method thereof will be described. It should be noted that matters other than matters particularly mentioned in this specification (such as formation conditions of the structure of a deposited film of an ultrafine silica compound or a film made of a granular silica compound) and matters necessary for the implementation of the present invention (plasma The configuration of the generator, the conditions for forming the metal film, etc.) can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and the drawings and common general technical knowledge in the field.
The manufacturing method of the super water-repellent material disclosed here essentially includes the following steps.
(1) Plasma is generated in an atmospheric pressure atmosphere into which an organosilicon compound is introduced with respect to a substrate having a metallic surface. Thereby, an ultrafine silica compound having an average particle diameter of 10 nm to 2000 nm is deposited on the substrate.
(2) The ultrafine particle silica compound is grown by exposing the substrate on which the ultrafine particle silica compound is deposited to an atmosphere containing an organosilicon compound. As a result, a film having a concavo-convex structure is formed on the surface formed by bonding granular silica compounds having an average particle diameter of 10 nm to 5000 nm.

1. Deposition of ultrafine silica compound In the production method of the present invention, as described above, it is derived from an organosilicon compound having an average particle size of 10 nm to 2000 nm on a substrate by plasma treatment under atmospheric pressure using an organosilicon compound as a raw material. The ultrafine silica compound is deposited.
[Base material]
In the present invention, as a substrate provided with a superhydrophobic film made of a granular silica compound (hereinafter sometimes simply referred to as superhydrophobic film), a metallic surface is provided at a site where the superhydrophobic film is provided. If it is a material provided, there will be no restriction | limiting in particular in a raw material etc. For example, the base material itself may be made of a metal material. Alternatively, the substrate is mainly composed of a material other than a metal material, for example, a glass material, a ceramic material, a resin material, or a composite thereof, and at least a part of the surface is provided with a metallic surface made of the metal material. It may be. As the metallic surface in this case, typically, a metallic film can be considered. For example, a metallic film is formed on a base material (base material main body) to form a base material having a metallic surface. be able to.

  That is, a step of preparing a base material having a metallic surface by forming a metal film on the base body in advance may be included before the above step (1). The method for forming the metal film on the base body is not particularly limited. For example, it can be appropriately selected from various known film formation methods according to the characteristics of the material constituting the base body. it can. As such film formation methods, for example, representative examples include a liquid phase film formation method typified by a sol-gel method, a spin coating ability, a sputtering method, a vapor deposition method, an ion plating method, and the like. Examples thereof include a chemical vapor deposition method (CVD method) represented by a physical vapor deposition method (PVD method), a thermal chemical vapor deposition method, a plasma chemical vapor deposition method, and the like. Especially, in this invention, it is shown as a preferable example to employ | adopt PVD method which can form a metal film with sufficient adhesiveness with respect to raw materials other than a metal material.

Although there is no restriction | limiting in particular in the form of a metallic surface, For example, by making thickness into about 1 micrometer or less, typically about 10 nm-500 nm, More preferably, about 10 nm-300 nm, making this metal film transparent. it can. Therefore, it can be suitably used for a base body and a metal film, and for applications such as electronics-related materials, optical materials, packaging materials, and the like.
There is no restriction | limiting in particular as a material which comprises this metallic surface, It can be set as various metals or its alloy. For example, when the metal film is made of copper (Cu), nickel (Ni), aluminum (Al), silicon (Si), silver (Ag), zinc (Zn) and iron (Fe), or an alloy thereof, such metal This is preferable because it can react with the spherical silica compound formed into a film and can improve the adhesion of the film made of the spherical silica compound.

[Organic silicon compound]
In the present invention, the organosilicon compound contains an organic group in which a Si—O—Si bond (which may be a network) is terminated with at least one organic group by the action of various radicals generated by plasma. Various compounds capable of forming silica can be used without particular limitation. Such an organosilicon compound may be a material widely known as a raw material compound used for SiO ₂ film formation by a plasma CVD method or the like. Specific examples of the organosilicon compound include, for example, (a) at least one organic functional group such as methyl group or ethyl group in Si-O-Si network having Si or Si as the main skeleton element. Examples thereof include a directly bonded compound, and (b) a compound in which an alkoxy group such as a methoxy group or an ethoxy group is bonded to an Si—O—Si network having Si or Si as a main skeleton element. More specifically, for example, silanes such as tetramethylsilane: Si (CH ₃ ) ₄ , tetramethoxysilane: Si (OCH ₃ ) ₄ , tetraethoxysilane: Si (OC ₂ H ₅ ) ₄ , tetraisopropoxy _{silane: Si (i-OC 3 H} 7) 4 tetra-tertiary butoxy _{silane: Si (t-OC 4 H} 9) alkoxysilanes such as _4, diisopropoxy di _{acetoxysilane: Si (OC 3 H 7)} 2 ( Chains such as alkoxyacetoxysilanes such as OCOCH ₃ ) ₂ (DADBS), hexathimethyldisiloxane: Si ₂ C ₆ H ₁₈ O (HMDS), tetramethyldisiloxane: Si ₂ C ₄ H ₁₂ O (TMDS) polysiloxanes, _{octamethylcyclotetrasiloxane: Si 4 C 8 H 24 O} 2 (OMCTS), Te La _{tetramethylcyclotetrasiloxane: Si 4 C 4 H 16 O} 4 (TOMCATS) or a cyclic polysiloxane such as. Any one of these may be used alone, or two or more thereof may be mixed and used.

[Deposition of ultrafine silica compounds]
In the present invention, the organosilicon compound as the raw material is deposited on a substrate as a silica compound in the form of ultrafine particles having an average particle size of 10 nm to 2000 nm. For the deposition of such ultrafine particle silica, a plasma vapor deposition (CVD) method can be employed, and in particular, a thermal plasma CDV method capable of stably forming ultrafine oxide particles near atmospheric pressure is used. More preferred.
For example, to explain using thermal plasma as an example, the plasma generation conditions can be appropriately set according to, for example, the configuration of the plasma generation apparatus, the type of the organosilicon compound that is a raw material, and the like.
There are no particular limitations on the thermal plasma generator, and various plasma generators (typically, plasma film forming apparatuses) can be used. For example, since the introduction of the raw material can be performed relatively easily, a plasma apparatus for thermal spraying using a DC arc discharge between the electrodes can be suitably used. In addition, the thermal plasma can be generated by multiphase discharge, inductively coupled discharge, atmospheric pressure microwave heating discharge, or the like, in addition to the generation method using the DC arc discharge.

  In the thermal plasma CVD method, an ultrahigh temperature plasma is generated in an atmospheric pressure atmosphere containing the above-mentioned organosilicon compound, which is a raw material of ultrafine silica, as a gas phase (typically, vapor), thereby generating the organic plasma. Synthesis and deposition of ultrafine particles of a compound derived from a silicon compound can be performed. In the thermal plasma CVD method, it is known that the generation process of fine particles typically includes a uniform nucleation step in a plasma tail flame part and a subsequent nucleation step. Therefore, it is preferable that the organosilicon compound in a gas phase is introduced in the vicinity of the plasma tail flame portion. The above organosilicon compounds are mostly liquid or solid at normal temperature, but generally, a carrier gas is introduced into the raw material keeping the temperature constant by utilizing the property of high saturated vapor pressure. By bubbling, a sufficient amount of raw material for forming the ultrafine silica compound can be supplied as a gas at a stable flow rate.

The organosilicon compound introduced into the plasma (typically the tail flame) together with the carrier gas is decomposed into atoms or ions in the plasma, and the chemical reaction is mainly performed between the plasma-atmosphere boundary layer and the plasma-group. It can be considered that it is dominated by non-equilibrium reaction processes in the boundary layer between materials.
Thus, for example, the plasma atmosphere can be freely selected according to the composition of the organosilicon compound that is the raw material of the ultrafine silica compound. Specifically, for example, an inert atmosphere using argon, an oxidizing atmosphere using oxygen, a reducing atmosphere using hydrogen, and the like can be freely selected, so that a desired decomposition treatment can be performed on the organosilicon compound. it can. For example, when a reducing environment is required to form an ultrafine silica compound from an organosilicon compound, the type of carrier gas can be prepared so that the plasma becomes a reducing plasma. For example, the carrier gas can include hydrogen gas. In addition, for example, when an oxidizing environment is required for forming an ultrafine silica compound from an organosilicon compound, the type of carrier gas can be adjusted so that the plasma is in an oxidizing atmosphere. For example, the carrier gas can include oxygen gas.

The organosilicon compound introduced as described above can exist mainly as a chemical species having a relatively small mass number in plasma. For example, specifically, chemical species containing Si are in the form of atomic Si, SiO, SiH, SiCHx, etc., and chemical species not containing Si are S, O, HC, H ₂ , CHx, OH, H _It can exist in the form of ₂ O, CO, CO _{2 and the} like. Of these, H, O, H ₂ , CH, OH and CO have been confirmed to exist in the gas phase by plasma emission spectroscopy. In addition, clusters having a large mass number have been confirmed by mass spectrometry up to the dimer of the raw material molecules, but the spatial density is low and it is considered that the cluster is not at a level involved in film formation. Therefore, Si, SiHx, and SiOx are considered as candidates for the precursor of the ultrafine silica compound.
Although the precursor of the ultrafine silica compound is not essential, it can be deposited on the substrate relatively stably by controlling the temperature of the substrate. Examples of such a substrate temperature include a range of about 50 ° C to 150 ° C.

The organosilicon compound activated in this way forms nuclei of ultrafine silica in the gas phase by riding on a plasma stream (uniform nucleation step). In the production method of the present invention, after such nucleation is performed, before the nucleation progresses excessively, that is, before the transition to the nucleation growth step, ultrafine particles having an average particle size of 10 nm to 2000 nm are performed. The silica compound is deposited on the substrate. The particle diameter of the ultrafine silica compound can be controlled by conditions such as the amount of raw material (organosilicon compound) supplied, the distance between the raw material supply port and the base material, the base material temperature, and the like.
In this way, the ultrafine silica compound deposited on the substrate by the thermal plasma method is deposited in the form of a powder with a fine outline of the silica compound containing air (with voids) between the particles. . In addition, the ultrafine silica compound is deposited geometrically randomly, and a large number of fine voids are formed between the fine particles so that a liquid phase (for example, water droplets) cannot enter. The fine concavo-convex structure formed by such ultrafine particles and voids can exhibit a super water repellency of 150 degrees or more as it is. However, the ultrafine particle silica thus formed is not firmly bonded to each other, and the adhesion to the substrate is not sufficient. And such ultrafine silica compounds can be very active and unstable.

2. Therefore, in the present invention, the substrate on which the ultrafine silica compound is deposited as described above is exposed to an atmosphere (typically vapor) containing an organosilicon compound. As a result, the vapor of the organosilicon compound is brought into contact with the surface of the ultrafine silica compound, and they are integrated by Si—O—Si bonds to grow the ultrafine silica compound. Thereby, the ultrafine particle silica compound can be grown (typically, vapor phase growth) into a granular silica compound having an average particle diameter of 10 nm to 5000 nm.
The organosilicon compound used here can be the same as that used for forming the ultrafine silica compound. Moreover, the ultrafine particle silica compound can be efficiently grown into a granular silica compound by placing the base material on which the ultrafine particle silica compound is deposited and the organosilicon compound in the same sealed container.

  Here, in the granular silica compound, particles adjacent to each other in the course of growth form a neck and are bonded together, and they are integrated by Si—O—Si bonding. That is, an integral film is formed from the deposit of ultrafine silica compound. In addition, with such grain growth, the gap formed between the adjacent granular silica compounds is reduced particularly in the region close to the base material, and a relatively dense film is formed. Furthermore, the granular silica compound and the metallic surface are chemically bonded to each other at a portion where the film made of the granular silica compound and the metallic surface of the substrate are in contact with each other. That is, when the vapor of the organosilicon compound reaches the substrate, it undergoes decomposition and chemical reaction to grow the ultrafine silica compound while taking over the crystal information on the metallic surface. Thereby, the strong coupling | bonding of the film | membrane which consists of a granular silica compound, and a base material will also be implement | achieved. Examples of the metal that is easily chemically bonded to silicon (Si) include copper (Cu), nickel (Ni), aluminum (Al), silicon (Si), silver (Ag), and zinc (Zn). Is done. Since the metallic surface of the base material is composed of such a metal, the particulate silica compound and the metallic surface are more preferably chemically bonded.

In the above growth process, in order to promote vaporization (generation of vapor) of the organosilicon compound, the organosilicon compound may be heated alone or in a sealed container. Although such heating is not an essential requirement, it can promote vapor phase growth by heating, and can strengthen the bond between particles due to the formation of the neck, film adhesion and mechanical strength Can be increased. Furthermore, the crystallinity of the particulate silica compound constituting the film can be increased, and the film strength can be further improved. Such heating can be appropriately performed according to the type of the organosilicon compound to be used, the material constituting the substrate, and the like. For example, specifically, it is preferable that the inside of the sealed container be at a temperature of 200 ° C. or higher (for example, 200 ° C. or higher and lower than 240 ° C.) because vaporization of the organosilicon compound can be effectively promoted. Further, for example, it is preferable to set the temperature in the sealed container to 240 ° C. or higher (for example, 240 ° C. or higher and lower than 260 ° C.) because the vapor phase growth of the ultrafine silica compound can be effectively promoted. In addition, for example, by setting the inside of the sealed container to a temperature of 260 ° C. or higher (for example, 260 ° C. or higher and lower than 300 ° C.), the adhesiveness of the film made of the granular silica compound can be rapidly increased. Further, it is more preferable that the inside of the sealed container is set to a temperature of 300 ° C. or higher (for example, 300 ° C. or higher and lower than 350 ° C.) because the hardness of the film made of the granular silica compound can be effectively increased. However, for example, heating above 350 ° C. is not particularly necessary, and for example, heating at a relatively low temperature of 350 ° C. or less may be preferable.
This makes it possible to produce a super water-repellent material having a super water-repellent film on the substrate with good adhesion.

  By the growth of the ultrafine silica compound described above, a film is formed by combining granular silica compounds having an average particle diameter of 10 nm to 5000 nm. The size of the granular silica compound can vary depending on the temperature conditions during vapor phase growth, the metal species constituting the metallic surface of the substrate and its crystallinity (crystal plane), the vapor phase growth time, and the like. The surface state of the film thus formed has a shape substantially similar to the deposition state of the ultrafine silica compound, and maintains a very complicated uneven structure with few flat portions.

  Although it is difficult to express its form appropriately, in general, the flat surface is disturbed in the process in which the ultrafine silica compound is preferentially deposited upward, and partial deposition occurs in the disordered portion. As it progresses, small protrusions grow. Further, the surface of the projection is disturbed, and further minute projections grow from the projection. However, since the ultrafine silica compound having a large surface energy (particularly the ultrafine silica compound at the tip) can also be deposited in the left-right direction (can be a bond between ultrafine silica compounds), for example, FIG. It is considered that a complicated uneven structure as shown is formed. In the vapor phase growth of the ultrafine silica compound, the growth proceeds by the deposition of the gaseous molecular organosilicon compound on the surface of the ultrafine silica compound in the same manner as above, and a granular silica compound is formed. . As a result, for example, a super water-repellent film that maintains the complicated shape as shown in FIG. 2B is formed. In this vapor phase growth stage, for example, the surface energy of the particles is increased by the atmospheric temperature, and bonding and integration of the granular silica compounds, surface flattening, and the like can occur. Further, the protrusions that are locally accumulated may be inclined obliquely or laterally, and may take a more complicated form.

For example, when the maximum thickness of the film is about 100 μm, the minimum thickness can be about 20 μm to 50 μm. In other words, the protrusions constituting the unevenness can have various heights in the range of about 50 μm to 80 μm. The space formed between the protrusions as a whole tends to expand as the thickness from the base material increases, but the particle size of the granular silica compound increases in the direction from which the thickness from the base material increases. There may be a narrowing portion with larger dimensions.
Such a shape is seemingly disordered and can exhibit self-affinity, although no perfectly fractal ordering is observed. And the water repellency with respect to water can show the super water repellency of 150 degree | times or more. That is, even after vapor phase growth, super water repellency of 150 degrees or more is maintained. That is, a super water-repellent material in which a transparent super water-repellent film is firmly bonded is provided.

  As described above, the super water-repellent material of the present invention and the manufacturing method thereof have been described based on the preferred embodiments. However, the configuration and the manufacturing method of the super water-repellent material are not limited to this example, and the mode is appropriately changed. Can be done. For example, the metallic surface to be formed on the substrate does not necessarily have to be formed by means of vacuum vapor deposition. For example, after forming a concavo-convex structure on the surface of the substrate, various types of low-pressure film methods such as plasma CVD are used. You may form by the film-forming method. Also, a device for generating thermal plasma can be suitably generated by, for example, a three-phase AC arc discharge type plasma torch. Needless to say, the conditions for generating the thermal plasma can be appropriately adjusted according to the conditions of the plasma generator, the organic silica compound, the base material, etc. that are actually used.

As described above, the method for producing a super water-repellent material of the present invention is understood to be a technique that can form a super water-repellent film on an arbitrary base material with good adhesion and at a relatively low temperature (for example, 350 ° C. or lower). be able to. Thereby, for example, a transparent super water-repellent film can be formed on an arbitrary substrate with good adhesion.
Next, examples relating to the present invention will be described, and the present invention will be described in more detail. However, it is not intended that the present invention be limited to that shown in such examples.

[Embodiment 1]
Using a glass substrate as a base material, a super water-repellent film was formed on the substrate by the following procedure to obtain a super water-repellent material.
1. Preparation of substrate In order to remove organic substances adhering to the surface of the glass substrate, the glass substrate and ethanol were placed in a beaker and washed with an ultrasonic cleaner for about 30 minutes. After the glass substrate taken out from ethanol was dried, the glass substrate and acetone were further put into a beaker and washed with an ultrasonic cleaner for about 30 minutes.

2. Formation of Metallic Surface In this embodiment, a copper (Cu) film as a metallic surface was formed on a glass substrate by employing a vacuum vapor deposition method that can be applied with a metal thin film relatively easily. That is, the glass substrate cleaned as described above is placed in a vacuum chamber, and the inside of the chamber is evacuated to 1 × 10 ⁻³ Torr with a rotary pump in a state where a Cu piece is placed on a plate-like filament, and further diffused The pressure was reduced to 1 × 10 ⁻⁵ Torr with a pump. Next, by energizing the filament, Cu was dissolved, and the generated Cu vapor was deposited on the glass substrate to form a Cu film. The Cu film was formed to a thickness of about 1 μm by opening and closing a shutter provided between the filament and the substrate. The glass substrate on which the Cu film was formed was stored in a drying container containing a silica desiccant.

3. Formation of Ultrafine Silica Compound A glass substrate on which a Cu film was formed was placed in a thermal spraying plasma generator shown in FIG. The glass substrate was placed 120 mm away from the plasma injection port so that the substrate temperature was about 100 ° C. In addition, a source gas to be described later was provided with an introduction port at a position where the distance from the substrate was 10 mm between the plasma injection port and the substrate.
First, the substrate was irradiated with plasma generated by applying a voltage of 24.8 V and a current of 25 A between plasma generating electrodes while supplying Ar gas as a carrier gas at a flow rate of 6 L / min for 5 minutes. Next, the substrate was irradiated with plasma generated by switching the carrier gas to Ar gas added with 1% H ₂ gas for 5 minutes. Then, TMCTS vaporized by injecting Ar gas into liquid 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) at a flow rate of 0.4 L / min and bubbling was used as a raw material gas, and 6 L / The substrate was irradiated with plasma generated while being introduced together with Ar gas for 7 minutes. Thereby, the ultrafine silica compound was deposited on the surface of the Cu film on the glass substrate.

Here, the glass substrate on which the ultrafine silica compound obtained above was deposited was broken, and the fracture surface and the surface were observed with a scanning electron microscope (SEM). The results are shown as FIG. 1 (a) fracture surface and (b) surface.
As shown in FIG. 1A, it was confirmed that ultrafine silica particles having a particle size of about several tens of .mu.m to several 0.1 .mu.m were deposited on the glass substrate. These ultrafine particles have a clear outline, nuclei of ultrafine particles are formed in the gas phase, and are synthesized as powder particles before the nucleus growth proceeds. You can see how it is gently deposited (with voids). The ultrafine silica compound was deposited randomly, and extremely complex and fine irregularities were formed on the outermost surface. In this case, the approximate deposition height (thickness) of the ultrafine silica compound was about 50 μm.

4). Growth of ultrafine silica compound The glass substrate on which the ultrafine silica compound obtained above is deposited and TMCTS placed in a glass container are sealed in a sealable stainless steel container and heated in an electric furnace. After heating to four temperatures of 5 ° C / min, (A) 240 ° C, (B) 260 ° C, (C) 270 ° C and (D) 290 ° C and holding at each temperature for 3 hours, The power was turned off and the furnace was cooled to room temperature. The glass substrates thus obtained were used as samples (A) to (D), respectively.
Samples (A) to (D) were fractured, and the fracture surface and the surface were observed with a scanning electron microscope (SEM). The results are shown in FIGS. 2A to 2D. For samples (A) to (C), (a) fracture surface and (b) surface observation results, and for sample (D), (a) fracture surface observation results and partially enlarged view (b) )showed that.

  As can be seen from the comparison of FIGS. 2A to 2D, it was confirmed that the particle size of the ultrafine silica compound increased and the deposition height (thickness) increased as the temperature of the heat treatment increased. For example, as shown in FIGS. 2D (a) and (b), the particle diameter of the ultrafine silica compound is increased to about several μm, and the average film thickness is increased to about 30 μm to 100 μm. I found out. It was also confirmed that each ultrafine silica compound was bonded to the surrounding silica by forming a neck, and the voids observed between the ultrafine silica compounds were reduced as a whole. Moreover, although the space formed between the particles tends to expand as the thickness from the substrate increases as a whole, for example, as shown in FIG. 2A (a), the space is parallel to the substrate. It was observed that there was a spreading part. It was also confirmed that as the thickness from the substrate increases, there may be many portions that narrow with a size larger than the particle size of the granular silica compound.

  Note that TMCTS used as a silica source has a boiling point of about 130 ° C., is easily vaporized, and is easily polymerized. From these facts, it was found that the ultrafine silica compound was grown by further exposing the ultrafine silica compound formed by the previous plasma thermal reduction treatment to the vapor of TMCTS. Since ultrafine silica is very active and unstable, it tends to become stable. Therefore, it is considered that, by applying thermal energy, the particles grow easily and grow under random deposition conditions to form bonds between the particles.

  Note that the Cu film provided on the glass substrate also tends to be active and stable. Therefore, as shown in FIG. 2D (b), it was confirmed that the ultrafine silica compound was in close contact with the Cu film.

[Evaluation]
[FT-IR analysis]
Among the samples prepared as described above, samples (B) to (D) in which the temperature when growing the ultrafine silica compound was (B) 260 ° C., (C) 270 ° C. and (D) 290 ° C. Then, Fourier transform infrared spectroscopy (FT-IR) was performed on the sample (X) on which the ultrafine silica compound was not grown, and the chemical bonding state in the deposit of the ultrafine silica compound was analyzed. For the measurement of the FT-IR spectrum, Fourier transform infrared absorption spectroscopy (FT-IR; manufactured by Shimadzu Corporation, FTIR8400S, control software; IRPreset-21) was performed. The results are shown in FIG.
Samples (B) to (D), which were not vapor-phase-grown, that is, vapor-phase-grown compared with sample (X) comprising ultrafine silica compound formed only by plasma thermal reduction coating, It was confirmed that the peak intensity attributed to each bond of CH _X- , Si-CH ₃ , Si-O-Si, Si-OH and Si-CH ₃ increased as the temperature during growth increased. . In addition, since the peak of Si—O—Si increased as the temperature during vapor phase growth increased, it was found that the crystallinity of the ultrafine particle silica compound was improved. Moreover, since the peak of Si—CH ₃ was remarkably increased as the temperature during vapor phase growth was higher, it was shown that the water repellency was also improved.

[Water repellency evaluation]
The contact angle of water was measured for the above samples (X) and (B) to (D). The contact angle is measured by using a contact angle measuring device (Kyowa Interface Science Co., Ltd., CA-Z), dropping a predetermined volume of pure water on the sample surface, and using a CCD camera after a certain period of time. The method of obtaining the contact angle by observing the water droplet shape was adopted.
As a result, it was confirmed that all samples had a water contact angle of 150 degrees or more and exhibited super water repellency. That is, even when the vapor phase growth temperature was raised to nearly 300 ° C., the contact angle was maintained at 150 ° or more. In addition, the water droplet dripped on the sample surface for the measurement was bounced without getting wet and became a substantially spherical shape, and it was observed that the sample surface was rolled by moving the sample slightly. From the situation at that time, it was predicted that the contact angle of water exceeded 150 degrees for samples (B) to (D).

[Scratch test]
In order to evaluate the film adhesion strength between the glass substrate and the deposited film of the ultrafine silica compound formed on the glass substrate, according to JIS R-3255 (Method for Adhesion Test of Thin Film Using Glass as Substrate) A scratch test was conducted using a scratch tester.
The sample used for this scratch test was prepared under the following conditions. That is, first, in the above “3. Formation of ultrafine silica compound”, the glass substrate is placed 120 mm away from the plasma injection port, and the plasma generated while supplying TMCTS and Ar gas is (1) 11 minutes and ( 2) Irradiated in two ways for 12 minutes. Next, the vapor phase growth temperature in “4. Growth of ultrafine silica compound” is changed between room temperature (25 ° C.) and a temperature of 200 ° C. or higher with respect to such a substrate. The conditions were the same as above. The scratch test conditions were as follows.

Diamond indenter tip shape: R = 10.0 μm
Load load speed: 54.13 mN / mm
Stage speed: 9.8 μm / sec
Stage angle: 3deg
FIG. 4 shows the critical load measured by such a test when the super water-repellent film starts to peel off from the glass substrate. In the figure, Δ indicates the critical load of a sample prepared by irradiating with plasma for 11 minutes, and ○ indicates the critical load of a sample prepared by irradiating with plasma for 12 minutes.
As is clear from FIG. 4, it was confirmed that the critical load rapidly increased when the temperature during vapor phase growth exceeded about 200 ° C. This is because the ultrafine silica compound grows, the silica and the Cu film on the surface of the substrate form a compound and binds firmly, and the crystallinity of the deposited film of the ultrafine silica compound by the formation of such a compound. In addition, it is considered that the adhesion with the substrate is greatly improved.

[Embodiment 2]
<Cu film>
The vapor phase growth temperature in “4. Vapor phase growth of ultrafine silica compound” in the first embodiment is 265 ° C., 280 ° C., 300 ° C., 330 ° C. and 350 ° C., and other conditions are the same as in the first embodiment. Then, a Cu film was formed on a glass substrate, deposition of an ultrafine silica compound by plasma thermal reduction, and vapor phase growth of silica were performed to form a deposited film (superhydrophobic film) made of ultrafine silica compound. In addition, when the vapor phase growth temperature was set to 350 ° C., a deposited film (super water-repellent film) made of an ultrafine silica compound was formed even under the condition that the holding time at such temperature was reduced from 3 hours to 1 hour. .

<Ni film>
A nickel (Ni) film was produced as a metallic surface to be formed on the glass substrate. That is, in “2. Formation of metallic surface” in Embodiment 1 above, Ni pieces were placed on the plate filaments instead of Cu pieces, and thereafter a metallic surface made of a Ni film was similarly formed. Thereafter, the vapor phase growth temperature in “4. Vapor phase growth of ultrafine silica compound” is set to 330 ° C. and 350 ° C., and the other conditions are the same as in the first embodiment. Water film) was formed. When the vapor phase growth temperature was 350 ° C., a deposited film (super water-repellent film) made of an ultrafine silica compound was formed even under the condition that the holding time at such temperature was shortened to 1 hour.

[Film hardness]
As described above, for the deposited film of ultrafine silica compound formed on the glass substrate, the film hardness was measured by the nanoindentation (indentation) method in order to evaluate the relationship between the film forming conditions and the film hardness. . For the measurement of film hardness, a nanoindenter (TI900-D, manufactured by Heiditron Co., Ltd.) was used. From the displacement and unloading curve when a triangular pyramid-type indenter was pushed into the sample surface with an initial contact load of 0.03 mN. The Meyer hardness pm (GPa) was calculated. The results are shown in FIG.
As shown in FIG. 5, it was confirmed that the film hardness of the deposited film of the ultrafine silica compound can be significantly increased by increasing the vapor phase growth temperature of the ultrafine silica compound. It was also confirmed that the film hardness could be increased by increasing the vapor phase growth time. In particular, it was confirmed that the film hardness can be remarkably increased by setting the vapor phase growth temperature to about 260 ° C. or higher.
In addition, when the metallic surface of the substrate is changed from a Cu film to a Ni film, or when the vapor phase growth time is changed, deposition of the resulting ultrafine silica compound is performed as compared with the case where the growth temperature is changed. No significant difference was observed in the film hardness of the film.

[Embodiment 3]
<Al film>
An aluminum (Al) film was produced as a metallic surface to be formed on the glass substrate. That is, in “2. Formation of metallic surface” in the first embodiment, an Al piece was placed on the plate filament instead of the Cu piece, and thereafter a metallic surface made of an Al film was formed in the same manner. Thereafter, the vapor phase growth temperature in “4. Vapor phase growth of ultrafine silica compound” is set to 265 ° C., and the other conditions are the same as in the first embodiment, and a deposited film (superhydrophobic film) made of ultrafine silica compound Formed.
The sample thus obtained was broken, and the surface and fracture surface were observed by SEM. As a result, an SEM image near the center of the surface is shown in FIG. 6A, and an SEM image of the cross section is shown in FIG.
As shown in FIG. 6, when the metallic surface is an Al film, the growth of ultrafine silica compound, bonding with the substrate (formation of Si—Al compound), 150, as in the case of the Cu film, It was confirmed that a deposited film of ultrafine silica compound having a water contact angle of more than 1 degree was obtained.

[Embodiment 4]
<Ni film>
In the present embodiment, a nickel (Ni) film is employed as the metallic surface formed on the glass substrate in “2. Formation of metallic surface” in Embodiment 1, and “4. Vapor phase growth of ultrafine silica compound”. The vapor deposition temperature in was set at 350 ° C., and other conditions were the same as in Embodiment 1, and a deposited film (super water-repellent film) made of an ultrafine silica compound was formed. When the vapor phase growth temperature was 350 ° C., a deposited film (super water-repellent film) made of an ultrafine silica compound was formed even under the condition that the holding time at such temperature was shortened to 1 hour.
The sample thus obtained was broken, and the surface and fracture surface were observed by SEM. As a result, the SEM image near the center of the surface is shown in FIG. 7A, and the SEM image of the cross section is shown in FIG. 7B.

  As shown in FIG. 7A, the ultrafine particle silica compound deposition film obtained is slightly different from the ultrafine silica compound deposition films obtained in Embodiments 1 to 3, and vapor phase growth is attempted at a high temperature. Nevertheless, the silica grain growth did not progress so much, rather it was close to the porous state formed by plasma thermal reduction. As can be seen from the cross-sectional image in FIG. 7 (b), in the deposited film of ultrafine silica compound, columnar silica particles grown to a thickness of about 2 μm were seen in a region close to the substrate, and the surface contained air. It was observed that the silica particles were deposited as softly. Further, it was found that the substrate was formed with a mixed layer of Si—Ni. However, it was confirmed that such a deposited film exhibits super water repellency with a water contact angle of 150 degrees or more. Further, as shown in FIG. 5, it was confirmed that the hardness was increased by heating by the vapor phase method.

[Embodiment 5]
In this embodiment, after depositing an ultrafine silica compound by plasma thermal reduction on a metallic surface composed of (a) Zn, (b) Cu, (c) Al, (d) Ag, and (e) Si, The ultrafine particle silica compound was vapor-phase grown to form a deposited film of the ultrafine silica compound.
Vapor phase growth was carried out under two conditions: (1) heating at 250 ° C. for 1 hour and (2) heating at 270 ° C. for 1 hour.
The obtained sample was fractured, the fractured surface was observed by SEM, and the results of observing the surface are shown in FIGS. As shown in FIGS. 8A to 8E, even when the metal species on the metallic surface was changed, it was confirmed that a film having a complicated concavo-convex structure formed of the granular silica compound was formed. Moreover, it was confirmed that each metal and silica reacted to form a compound between the metallic surface and the deposited film.
In addition, the physical properties of the obtained deposited film of the granular silica compound were all the same as those in the first embodiment, and it was confirmed that both super water repellency and high film adhesion were compatible.

[Embodiment 6]
In this embodiment, after depositing an ultrafine silica compound on a metallic surface made of SUS steel by plasma thermal reduction, the ultrafine silica compound was vapor-phase grown to form a deposited film of the ultrafine silica compound.
Vapor phase growth is performed under two conditions: (1) heating at 250 ° C. for 1 hour and (2) heating at 270 ° C. for 1 hour. Samples (1) and (2) are Obtained.
The obtained sample (1) was broken and the fractured surface was observed by SEM. The results are shown in FIG. 9A and the sample (2) is shown in FIG. 9B. As can be seen from these figures, a granular silica compound having a diameter of 1 to 2 μm is bonded to the sample (1), and a granular silica compound having a diameter of approximately 1 to 4 μm is bonded to the sample (2) at the neck. Accumulation was confirmed. As a result of the scratch test for each sample, a critical load of 77 mN was obtained for sample (1) and a critical load of 125 mN was obtained for sample (2). Moreover, about the water repellency, all the samples were 150 degree | times or more.
Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The invention disclosed herein can include various modifications and alterations of the specific examples described above.

Claims (11)

By depositing an ultrafine particle silica compound having an average particle size of 10 nm to 2000 nm on the substrate by generating plasma in an atmospheric pressure atmosphere into which the organosilicon compound is introduced with respect to the substrate having a metallic surface. ,
The ultrafine particle silica compound is grown by exposing the substrate on which the ultrafine particle silica compound is deposited to an atmosphere containing the organosilicon compound at a temperature of 200 ° C. or higher, and a granular silica compound having an average particle size of 10 nm to 5000 nm is obtained. A method for producing a super water-repellent material, comprising forming a film having a concavo-convex structure on surfaces bonded to each other. Further, the method includes a step of forming a metal film on a base material to prepare a base material having the metallic surface,
The metal film is at least one selected from the group consisting of copper (Cu), nickel (Ni), aluminum (Al), silicon (Si), silver (Ag), zinc (Zn), and iron (Fe). They comprise a metal or an alloy thereof, method for manufacturing the super water-repellent material of claim 1. The method for producing a super water-repellent material according to claim 2 , wherein the metal film is formed to a thickness of 1 μm or less. The method for producing a super water-repellent material according to any one of claims 1 to 3 , wherein glass or a resin material is used as the substrate. A substrate having a metallic surface;
Provided on the substrate, the average particle size becomes bonded particulate silica compound of 10nm~5000nm each other, and a film having an uneven structure on the surface,
The concavo-convex structure has protrusions formed by depositing the granular silica compound in a direction perpendicular to the surface of the substrate, and the granular silica compound is deposited in a direction parallel to and / or oblique to the surface of the substrate. A super-water-repellent material , comprising : The super water-repellent material according to claim 5 , wherein a contact angle of water on the surface of the film is 150 degrees or more. The super water-repellent material according to claim 5 or 6 , wherein a reaction layer formed by a reaction between the film and the metallic surface is formed at an interface between the film and the metallic surface. The super-water-repellent material according to claim 5 , wherein the metallic surface has a thickness of 1 μm or less. The superhydrophobic material according to any one of claims 5 to 8 , wherein a critical load when the film is peeled from the substrate based on a scratch test is 50 mN or more. The substrate is glass or resin,
The metallic surface is at least one selected from the group consisting of copper (Cu), nickel (Ni), aluminum (Al), silicon (Si), silver (Ag), zinc (Zn) and iron (Fe). The super water-repellent material according to any one of claims 5 to 9 , wherein the super water-repellent material is made of any of the above metals or alloys thereof. A super water-repellent material in which a granular silica compound having an average particle size of 10 nm to 5000 nm is bonded to each other on a base material having a metallic surface, and a film having a concavo-convex structure is provided on the surface,
The membrane is
Depositing an ultrafine silica compound having an average particle size of 10 nm to 2000 nm on the substrate by generating plasma in an atmospheric pressure atmosphere in which an organosilicon compound is introduced to the substrate;
The ultrafine particle silica compound is grown by exposing the substrate on which the ultrafine particle silica compound is deposited to an atmosphere containing the organosilicon compound at a temperature of 200 ° C. or higher, and a granular silica compound having an average particle size of 10 nm to 5000 nm is obtained. Forming a film having a concavo-convex structure on surfaces bonded to each other;
Super water-repellent material manufactured by