Method of tunning wettability of titanium dioxide layers against water

Abstract

The present invention relates to a method of tunning wettability of titanium dioxide layers against water by nanostructuring the titanium dioxide layers to increase a hydrophilicity of the titanium dioxide layers, and also coating the nanostructured titanium dioxide layers with silane layers to increase a hydrophobicity of the titanium dioxide layers. The method of tunning wettability of titanium dioxide layers against water according to the present invention comprises: (a) step of forming titanium dioxide layer on a substrate; (b) step of forming silica particle layers on the upper part of the titanium dioxide layer; (c) step of etching a surface of the laminate prepared in step (b); and (d) step of removing the silica particle layer etched and remained in the step (c).

What is claimed is: 
     
         1 . A method for forming a nanostructured titanium dioxide layer, the method comprising:
 (a) step of forming a titanium dioxide layer on a substrate;   (b) step of forming a number of particle layers on the upper part of the titanium dioxide layer as an etching mask;   (c) step of etching a surface of the titanium dioxide layer as an etching mask to form a nanostructure on the surface of the titanium dioxide layer by the etching; and   (d) step of removing the residual particle layer.   
     
     
         2 . The method for forming a nanostructured titanium dioxide layer according to  claim 1 , wherein the particle layer is a silica particle. 
     
     
         3 . The method for forming a nanostructured titanium dioxide layer according to  claim 2 , wherein the titanium dioxide layer in the step (a) is formed by a sol-gel method, sputtering method or thermooxidation method. 
     
     
         4 . The method for forming a nanostructured titanium dioxide layer according to  claim 2 , wherein the silica particle layer in the step (b) is formed by Langmuir-Blodgett process. 
     
     
         5 . The method for forming a nanostructured titanium dioxide layer according to  claim 4 , wherein the surface pressure of the silica particle layer in the Langmuir-Blodgett process is 10˜12 mN/m. 
     
     
         6 . The method for forming a nanostructured titanium dioxide layer according to  claim 4 , wherein the silica particle layer is a self-assembling monolayer. 
     
     
         7 . The method for forming a nanostructured titanium dioxide layer according to  claim 2 , wherein the etching in the step (c) is conducted by ICP etching method or reaction-ion etching method. 
     
     
         8 . The method for forming a nanostructured titanium dioxide layer according to  claim 7 , wherein the etching is conducted for 10-40 sec. 
     
     
         9 . The method for forming a nanostructured titanium dioxide layer according to  claim 2 , wherein after conducting the step (d) a silane layer is formed on the surface of the nanostructured titanium dioxide layer to increase the hydrophobicity. 
     
     
         10 . The method for forming a nanostructured titanium dioxide layer according to  claim 9 , wherein the silane layer is consisted of one or more of silane being selected from the group consisting of 1H,1H,2H,2H-perfluorooctylchlorosilane, octadecyltrichlorosilane, (tridecanfluoro-1,1,2,2-tetrahydrooctyl)-1-trichlorosilane, 3,3,3-trifluoropropyl-trichlorosilane, and dodecyltrichlorosilane. 
     
     
         11 . In a structure that a control of wettability against water is possible, the structure comprising:
 a substrate; and   a titanium dioxide layer formed on the substrate, wherein the titanium dioxide layer has a surface on which a number of nanostructures in a cone shape is formed.   
     
     
         12 . The structure according to  claim 11 , further comprising a silane layer that is coated on the upper part of the titanium dioxide layer.