A Multilayer Strategy for Improving the Abrasion Resistance of Silica Nanoparticle-Based Motheye Antireflective Coatings on Glass

Motheye antireflective coatings (ARCs) are based on periodic or stochastic features with dimensions below the wavelength of visible light which can be used to produce a gradient index of refraction between air and the substrate. In this work, two silica nanoparticle-based motheye ARCs of similar optical performance, but different physical structures, were deposited on glass and characterized for mechanical behavior to provide insights into the mechanisms for abrasion resistance in these films. Optical and mechanical performances were evaluated in light of the mechanical properties and physical structure of the films using models for describing the mechanical behavior of the films. The results show that the three-layer coating was found to have better abrasion resistance than a simple single layer coating largely due to better crack nucleation resistance and scratch resistance. The simple single-layer film showed better crack propagation resistance than the three-layer film due to the existence of nanoparticles (NPs) throughout the cross section of the film. The three-layer film appears to have higher work of adhesion based on exhibiting better delamination and spallation resistance.