K. Tadanaga et al., Preparation of super-water-repellent alumina coating film with high transparency on poly(ethylene terephthalate) by the sol-gel method, CHEM LETT, (8), 2000, pp. 864-865
Al2O3 gel films were prepared on poly(ethylene terephthalate) substrates fr
om Al(O-sec-C4H9)(3) chemically modified with ethyl acetoacetate. A small r
oughness of about 20-50 nm was found to form on the Al2O3 gel films dried a
t room temperature and then immersed in hot water at 60 degrees C. When hyd
rolyzed fluoroalkyltrimethoxysilane was coated on the Al2O3 films, transpar
ent thin films with contact angle for water to be more than 150 degrees wer
e obtained.