Sol-gel based antireflective coatings with superhydrophobicity and exceptionally low refractive indices built from trimethylsilanized hollow silica nanoparticles

Abstract

We reported the preparation of antireflective (AR) coatings with superhydrophobicity and ultralow refractive indices (as low as 1.08) at room temperature from sols containing hexamethyldisilazane (HMDS)-functionalized hollow silica nanoparticles (HSNs) via a sol-gel process. The prepared sols were suitable for large area processing with ease of coating and being directly applicable without requiring any post-treatment. The water contact angles (WCAs) of the resulted coatings increased from 15° to 156° with the increase of HMDS content, which afforded the coatings superior water repellency properties. Besides this, HMDS-functionalized HSNs-based layer produced a fair antireflection effect consisting of more than a 4% increase in optical transmittance. These multifunctional coatings may find potential applications in fields of electronics, and optical devices.