Superhydrophobic Antireflection Coating on Glass Using Grass-like Alumina and Fluoropolymer

This work presents a superhydrophobic antireflective (AR) coating on glass. The coating consists of a grass-like alumina layer capped with plasma-deposited fluoropolymer. The grass-like alumina is formed by hot water treatment of atomic layer-deposited alumina on glass, and the fluoropolymer is plasma-deposited from CHF₃. Excellent broadband AR performance is observed in the visible spectrum with an average transmission of 94.9% for single-sided coated glass, which is close to the maximum 95.3% possible for this glass. Extremely desirable contact angles are obtained with 5-7 min-long fluoropolymer treatments on grass-like alumina with 173° advancing and 160° receding contact angles. This type of multifunctional coating can be beneficial in a multitude of applications like self-cleaning AR coating for solar panels, windows in high-rise buildings, sensors, and aerospace applications as well as just utilizing the excellent water repellent behavior in applications where only superhydrophobicity is required.