Preparation of chitin nanofibers through esterification and partial deacetylation followed ultrasonic treatment and their application for antireflective coating

Chitin nanofibers (ChNFs) are emerging as a very attractive material due to their biocompatibility, renewability, and excellent mechanical properties. ChNFs have broad applications in various fields. In this paper, ChNFs were prepared from commercially available chitin power through a dual modification of esterification with maleic anhydride followed partial deacetylation and subsequent ultrasonic treatment. Meanwhile, potential application of the ChNFs in antireflective coatings was explored. It was found that, as the deacetylation reaction time increased, the ChNFs became finer and more uniform. The ChNFs were positively charged under acidic conditions and negatively charged under basic conditions. At pH of 3.5, the ChNFs were dispersed well in water and the ChNF suspension showed excellent stability. The ChNF coatings fabricated by casting the ChNF suspensions with pH of 3.5 on glass substrate possessed antireflective capacity and yielded a 3 % transmission gain in the wavelength range of 390–800 nm compared to the uncoated glass.