Omnidirectional Antireflective Coatings Fabricated via Freeze Casting of Chitin Nanofibers

Introducing nanopores into antireflective coatings can further enhance their antireflective capacity. Antireflective coatings based on chitin nanofibers (ChNFs) and methyltrimethoxysilan were first fabricated via freezing casting. Effects of the moisture content and freeze temperature on the refractive index and antireflective capacity were investigated. Refractive index of the coating reached 1.28, and the transmittance gain of a glass slide with the coating was up to 6.2% at wavelength of 550 nm. The results of this study demonstrate that freeze casting is a feasible and efficient way to fabricate ChNF antireflective coatings with lower refractive indexes on large size substrates at low cost.