Preparation and properties of organic-inorganic modified SiO₂ thin films

Polydimethylsiloxane (PDMS), tetraethoxysilane (TEOS), ethyl alcohol (EtOH) and deionized water were main raw materials to prepare silicone-modified hybrid thin films using sol-gel method. The effect of the contents of H₂O and PDMS on thin films was studied. When the volume ratio of H₂O to TEOS is 0.5, the optimum quality of thin films is obtained. And the gelation time is affected slightly by H₂O content. Uniform thin films are obtained when the volume ratio of PDMS to TEOS is 0.2. Yet, the sol would be inactive in 6 d. Various properties of thin films were studied, including hardness, adhesive quality, hydrophobic property, corrosion protection property, and abrasion resistance. Test results show that the pencil hardness is generally 3-6 H, and adhesive quality achieves the highest standard of 0. When the sintering temperature is below 400 C, the contact angle is about 95 and hydrophobic films are obtained. The abrasion resistance of thin films is better than that of aluminum alloy when the sintering temperature is higher than 300 C. And the excellent corrosion protective effect is obtained by single-layer coating when the sintering temperature is higher than 400 C.