JPH02101195A - Formation of thin film - Google Patents

Abstract

PURPOSE:To form a film on a substrate of a large area by a wet process with particles of a water insoluble inorg. material by dispersing the inorg. material in a micelle soln. of a surfactant which is charged by electrolysis to form colloid and by carrying out electrolysis in the micelle soln. to electrolyze the micelle. CONSTITUTION:A surfactant which forms micelle easily because of the low critical micelle concn. and is charged by electrolysis is dissolved to the critical micelle concn. or above to prepare a soln., particles of an inorg. material are dispersed in the soln. and a supporting electrolyte such as NaCl or Na2SO4 is added. Electrodes are then immersed in the soln. and electrolysis is carried out at higher electrolytic potential of the surfactant used. In the case of PEQ having +0.2V oxidation potential to a satd. calomel electrode(SCE), the deposition of the dispersed particles is initiated by impressing >+0.2V potential. The inorg. material incapable of being wet-formed into a film by the conventional technique can be wet-formed into a film.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves forming a film of water-insoluble inorganic particles by an electrochemical method, and forming a film of water-insoluble inorganic material particles on an electrode to improve its adhesion. (Regarding the method of forming.

[Prior Art] Conventionally, there has been no method for forming a film of water-insoluble inorganic particles on an electrode in an aqueous solution except for the plating method. The metals that can be formed into films are limited by the Metsuki method, and it is impossible to form films of inorganic compounds.

For this reason, as a method for forming inorganic films, so-called dry film formation such as sputtering and vaporization 7Fr t CVD + pyrosol method has only become popular recently.
Saji et al. (J
,A,m,Ohem,Soc, ,1095
881 (1987), Ohem, Lett, 893 (
198B)) reports on the electrolytic method of Kamicel, but only reports on some azo and phthalocyanine pigments.

As a result of intensive research, we have discovered that it is possible to form films of inorganic particles by applying the micelle electrolysis method described above, and therefore we hereby patent this invention [Problem to be solved by the invention] As described above. With conventional techniques, it has not been possible to form a film of an inorganic material by a wet method, except for metal film formation by a plating method. For this reason, there has been a problem in that dry methods such as sputtering, vapor deposition, OVD, and pyrosol must be relied upon for film formation of other inorganic materials. For example, methods such as sputtering, evaporation, and some OVD require a vacuum setup θm, which poses problems such as expensive equipment and difficulty in forming a film on a large substrate. Further, some CVD methods, pyrosol methods, etc., have problems such as being limited in the materials that can be used to form the film, since the substrate is heated to a temperature of several hundred degrees Celsius or higher to form a film.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and its purpose is to provide a method for forming inorganic particles onto a large-area substrate using a wet method at low temperatures.

[Means for Solving the Problems] The present invention involves dispersing a water-insoluble inorganic substance into a colloid in a micelle solution of a surfactant that has the property of being charged by electrolysis, and performing electrolysis in the core micelle solution to form micelles. Den JIP
(As a surfactant that forms a film of inorganic particles on the electrode by It is sufficient that the particles collapsing due to repulsion between the micelles and the particles trapped in the micelles are deposited on the electrode. There are surfactants having a metallocene group, and commercially available ones include ferrocenyl pgo, which incorporates ferrocene.

This surfactant is dissolved in water to a concentration higher than the critical micelle concentration, and inorganic particles are dispersed therein.

The surface of the inorganic material particles must be hydrophobic because the inorganic material particles enter a stable dispersion state by being incorporated into micelles in an aqueous solution.

If the material is hydrophilic, it is necessary to coat the surface with a hydrophobic polymer film or to make the surface hydrophobic using an organic metal compound.

In addition, as supporting electrolytes, Na0t, Na, 5o4Li
Any electrolyte such as Br or Li□S04 may be used.

Next, the electrode is immersed in this solution and electrolysis is performed, and the electrolytic potential only needs to be higher than the oxidation or reduction potential of the surfactant used. For example, since the oxidation potential of ferrocenyl PIG is 10.2 V with respect to a saturated calomel electrode (SOE), precipitation of dispersed particles begins when a higher potential is applied.

This will be explained in detail below using examples.

[Example] (Example 1) As a surfactant, ferrocenyl PEG (manufactured by Isotope Kagaku Co., Ltd.) having a metallocene group into which Fe was introduced was used. A 4 mM aqueous solution of ferrocenyl PEG was prepared, and LiBr was adjusted to a concentration of 0.1 M/l as a supporting electrolyte.

Carbon powder with a particle size of 0.05 μm was added to this solution as an inorganic material for 15 minutes. i' and dispersed using an ultrasonic homogenizer.

Next, a platinum plate as a counter electrode, a saturated calomel electrode (SOE) as a reference electrode, and a glass with ITO as a sample electrode were immersed in this dispersion solution, and the electrolytic potential was set to SOE+ 0.5.
Electrolysis was carried out at V for 1 hour. Through these operations, a carbon film was formed on the ITo.

(Example 2) The same aqueous solution of ferrocenyl PEG as in Example 1 was prepared, and silica sol 157, which had been subjected to a hydrophobic treatment as an inorganic material, was added to this solution and dispersed with an ultrasonic homogenizer.

Next, a platinum plate as a counter electrode, a saturated calomel electrode (SCE) as a reference electrode, and a glass with ITo as a sample electrode were immersed in this dispersion solution, and the electrolytic potential was +0.5 with respect to SOE.
Electrolysis was carried out for 1 hour at ■. By these operations, S i 02
A film was formed on ITO [Effect of the invention] As can be seen from the above examples, it has become possible to form a film of an inorganic material, which was impossible to form using a wet method using the conventional technology. As a result, it is now possible to easily and inexpensively form a film over a large area, which was previously considered difficult to do using dry film formation methods.

that's all

Claims (1)

[Claims] A water-insoluble inorganic substance is dispersed into a colloid in a micelle solution of a surfactant that has the property of being charged by electrolysis, and electrolysis is performed in the micelle solution. By electrolyzing the micelles, a film of inorganic particles is formed on the electrode. A thin film forming method characterized by forming.