Self-cleaning hydrophobic nanocoating on glass: A scalable manufacturing process

Abstract

A method of forming a self-cleaning hydrophobic nanocoating (SCHN) on glass substrates utilizing a scalable manufacturing process is described. The process initiates with roughening of planar glass surfaces using diamond micro-/nano-particle abrasives, which creates microscopic tortuous grooves. After cleaning the substrates, the roughened surface is vapor deposited with trichloro (1H,1H,2H,2H-perfluorooctyl)silane (TCPFOS) under enclosure with controlled humidity. TCPFOS chemically binds with the substrate via covalent linkage. Due to the greatly reduced surface tension between water and the self-cleaning surface, the water droplet slides down leaving no trail (sliding angle of 14° for 0.1 mL water droplet). Due to the reduced adhesion of dirt to the self-cleaning surface, the dirt particles are washed away by sliding or rolling water droplets. The SCHN shows a negligible change in transmission as compared to the original glass substrate. The coating is resistant to multiple environmental factors including abrasion cycles, acid rain (pH = 3), saline exposure (10% w/v), alkali solution (pH 11, NaOH), and extreme temperature cycling (−10 to 60 °C).