Formation of Superhydrophobic Alumina Coating Films with High Transparency on Polymer Substrates by the Sol-Gel Method

摘要

Transparent,superhydrophobic coating films have been prepared on polymer substrates at low temper- atures through the sol-gel method.Al_2O_3 gel films were prepared on poly (ethylene terephthalate) substrates from Al(O-sec-C_4H_9) chemically modified with ethyl acetoactate.A small roughness of about 20-50 nm was found to form on the surface of the Al_2O_3 gel films dried at room temperature and then immersed in hot water at 60 deg C.The electron differctio measurements have shown that this roughened surface consists of pseudobodhmite manocry stals.The coating of hydrolyzed fluoroalkyitrimethoxysilane on the Al_2O_3 gel films with the small roughness produced transparent,superhydrophobic films with contact angle for water larger than 150.