Preparation of octyltrimethoxysilane modified SiO2 hydrophobic antireflective coating

Abstract

The standard SiO2 sol was prepared by sol-gel process using tetraethylorthosilicate (TEOS) as precursor and ammonia as catalyst. Octyltrimethoxysilane (OTMS) was added into the standard SiO2 sols before and after refluxing to obtain different organosilane modified silica sols, respectively. Silica antireflective (AR) coatings were then prepared from different SiO2 sols by dip-coating method. The optical and structural properties of the AR coatings were characterized by Fourier transform infrared spectroscopy, liquid-state 29Si NMR, UV-Vis-NIR spectrometer, atomic force microscope and water contact angle measurement. The results show that the AR coating prepared from OTMS modified before refluxing has the best moisture-resistant performance. The coated glass substrate obtains a high peak transmittance of 99.7%, with water contact angle of 120°. After been placed in a humid environment for 4 w, the transmittance of SiO2 coatings modified before refluxing is decreased only by 0.23%.