Preparation of hydrophobic antireflective SiO2 coating with deposition of PDMS from water-based SiO2-PEG sol

The classic sol-gel method for preparing antireflective coatings (ARCs) known for decades often employs an organic liquid as the solvent, so it is necessary to develop an environmental- friendly and feasible procedure for commercial ARC fabrication. Herein, self-cleaning ARCs were prepared from water-based silica hydrosols followed by a chemical vapor deposition process. The average transmittance rose remarkably after the dip-coating of silica hydrosols. Polyethylene glycols (PEGs) with molecular weights of 1000, 2000 and 4000 were adopted as template agents to lower the refractive index of the coatings and thus enhance the antireflective performance. The PEG1000-modified coating has the highest average transmittance of 96.44%. Field-emission scanning electron microscopy and atomic force microscopy showed the surface roughness increased with the rise of molecular weight of PEG and the coating from PEG1000 is relatively smooth. Water contact angle measurement and anti-smudge test showed the chemical vapor deposition endowed the ARCs with hydrophobicity and self-cleaning ability.