RU2450984C1 - Method of producing silicon dioxide-based thin nanostructured single-layer coatings via sol gel method in presence of inorganic acids and salts thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method of producing silicon dioxide-based thin nanostructured single-layer coatings involves a silicon tretraalkoxide sol gel process in the presence of an additive of hydrochloric acid and yttrium chloride, in the presence of which, after heating, a transparent silicon dioxide-based film having an antireflection effect is formed. A film-forming solution is prepared with the following ratio of components, wt %: tetraethoxysilane 4.37-5.81, yttrium chloride crystalline hydrate 6.65-8.67, hydrochloric acid - 0.01, 96 wt % ethyl alcohol being the balance. After maturation, the film-forming solution is deposited onto a glass substrate and subjected to thermal treatment in steps. The sample is heated in an air atmosphere at 500-700°C for one hour.

EFFECT: shorter time for obtaining an antireflection nanoporous coating.

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Description

The invention relates to thin-film interference coatings for the illumination of optical elements.

A known method of producing mesoporous mixed oxides of ZrO ₂ -SiO ₂ (article V. N. Viter "Sol-gel synthesis of mesoporous mixed oxides ZrO ₂ -SiO ₂ " // Journal of Applied Chemistry, 2010, V.83, Issue 2. C. 198-202) sol-gel method using zirconium oxochloride ZrOCl ₂ · 8H ₂ O and tetraethylorthosilicate Si (OEt) ₄ in an aqueous-ethanol medium in the presence of nitric acid. The calculated amount of ZrOCl ₂ · 8H ₂ O was dissolved in water, ethyl alcohol, Si (OEt) ₄ and HNO ₃ were added. The mixture was heated in a water bath at 60 ° C for 1-3 hours, the obtained gels were dried and annealed to obtain oxides. The disadvantage of this method is to obtain mesoporous oxide systems only in the form of xerogel powders, which limits the scope of their practical use.

A known method of producing thin antireflective coatings based on mesoporous silica sol-gel method (article B. B. Troitsky, V. N. Denisov, M. A. Novikov and others. "Obtaining thin antireflection coatings based on mesoporous silica sol-gel method in the presence of carbochain polymers, static copolymers // Journal of Applied Chemistry, 2008. V.81. Issue 8. P.1365-1369) with a low refractive index of 1.25-1.34 when using carbochain polymers and static copolymers. A film-forming solution was prepared on the basis of tetraethoxysilane, isopropyl alcohol, polyvinyl butyral or povivilin acetate and hydrochloric acid. Coatings were obtained on their glass substrates in the following mode: coated glasses were left at room temperature for 12 hours, then coated glasses were placed in a thermostat at 150 ° C and heated at a rate of 5 deg · min ^-1 to a temperature of 500 ° C, at this temperature was maintained for 5-6 hours. A disadvantage of the known method for producing a thin-film single-layer coating is a multi-stage mode of production and the length of time of receipt.

A known method of producing thin antireflection coatings based on mesoporous silica by the sol-gel method in the presence of ethylene oxide oligomers, propylene oxide oligomers (RF patent 2368576, publ. 09/27/2009, С03С 17/30), selected as a prototype.

The method for producing thin 50-150 nm single-layer antireflection coatings with a low refractive index of 1.23-1.26 based on mesoporous silica on silicate glass products with a transmission maximum of 98.7-99.0% in the visible region of the spectrum includes a sol -gel process of silicon tetraalkoxide in the presence of an organic additive in a concentration of 0.1-5.0 wt.%, preferably 1.0-3.5 wt.% to the weight of the sol, using the EISA technique, heating the sample with coatings in air at 300-600 ° C for several hours with the aim of thermal destruction of organic tion additive. As an organic additive, which determines the spontaneous micro-separation of inorganic and organic phases during the formation of a solid coating on glass, ethylene oxide oligomers and propylene oxide oligomers of various molecular weights are used.

The disadvantages of this method is the length of the process for producing thin antireflection coatings due to the use of an organic additive, which takes several hours to decompose thermally.

The objective of the present invention is to develop a method for producing thin nanostructured single-layer coatings based on silicon dioxide by the sol-gel method in the presence of inorganic acids and their salts in order to reduce the time to obtain antireflection nanoporous coating.

The problem is solved in that the method for producing thin nanostructured single-layer coatings based on silicon dioxide by the sol-gel method in the presence of inorganic acids and their salts includes the sol-gel process of silicon tetraalkoxide (tetraethoxysilane) in the presence of an additive in the presence of which in the sol-gel process with subsequent heating of the coated sample forms a transparent film of silicon dioxide with an antireflection effect, but unlike the prototype, the sample is heated in an atmosphere of air at 5 00-700 ° C for one hour, hydrochloric acid, yttrium chloride are used as additives in the following ratio of components, wt.%:

Tetraethoxysilane - 4.37-5.81

Yttrium chloride crystalline hydrate - 6.65-8.67

Hydrochloric acid - 0.01

96% wt. ethyl alcohol - the rest.

Examples of specific embodiments of the invention are given below.

Example 1

To prepare 100 ml of a film-forming solution, it is necessary to take 8.67 g of crystalline hydrate of yttrium chloride and dissolve it in 70 ml of 96 wt.% Ethanol, then add 4.10 ml of tetraethoxysilane with a density of 0.94 g / cm ³ , then add 0.01 ml of hydrochloric acid with a density of 1.19 g / cm ³ and bring to a volume of 100 ml with ethyl alcohol. After the solution has matured for 24 h, POR is applied to the glass substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 700 ° C for 1 h, and a thin film of mesoporous silicon dioxide with a thickness of 75 nm is obtained with a low refractive index of 1.26 due to the antireflection effect.

Example 2

To prepare 100 ml of a film-forming solution, it is necessary to take 7.12 g of crystalline hydrate of yttrium chloride and dissolve it in 70 ml of 96 wt.% Ethanol, then add 4.80 ml of tetraethoxysilane with a density of 0.94 g / cm ³ , then add 0.01 ml of hydrochloric acid with a density of 1.19 g / cm ³ and bring to a volume of 100 ml with ethyl alcohol. After the solution has matured for 24 h, POR is applied to the glass substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 700 ° C for 1 h, and a thin film of 55 mesoporous silicon dioxide is obtained nm with a low refractive index of 1.25 due to the antireflection effect.

Example 3

To prepare 100 ml of a film-forming solution, it is necessary to take 6.65 g of crystalline hydrate of yttrium chloride and dissolve it in 70 ml of 96 wt.% Ethanol, then add 5.46 ml of tetraethoxysilane with a density of 0.94 g / cm ³ , then add 0.01 ml of hydrochloric acid with a density of 1.19 g / cm ³ and bring to a volume of 100 ml with ethyl alcohol. After the solution has matured for 24 h, POR is applied to the glass substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 700 ° C for 1 h, and a thin film of the composition of mesoporous silicon dioxide with a thickness of 95 nm is obtained with a low refractive index of 1.25 due to the antireflection effect.

Claims (1)

A method for producing thin nanostructured single-layer coatings based on silicon dioxide by the sol-gel method in the presence of inorganic acids and their salts, comprising the sol-gel process of silicon tetraalkoxide in the presence of an additive, in the presence of which a transparent film forms in the sol-gel process, followed by heating the coated sample based on silicon dioxide with an antireflection effect, characterized in that the heating of the sample is carried out in an atmosphere of air at 500-700 ° C for one hour, as an additive Brine acid, yttrium chloride at the following component ratio, wt.%:
Tetraethoxysilane 4.37-5.81 Yttrium chloride crystalline hydrate 6.65-8.67 Hydrochloric acid 0.01 96 wt.% Ethyl alcohol Rest