Superhydrophobic chitosan films via SiO2/PDMS coating for reducing liquid food residue

Superhydrophobic coatings have gained significant interest due to their ability to prevent liquid foods like juice and yogurt from adhering to the inner surfaces of containers, thus reducing waste. Superhydrophobic coatings limit its application due to its toxicity, degradability and other reasons. In this work, chitosan sodium phytate films were deposited on glass plates by layer-by-layer self-assembly (LBL), then SiO2 nanoparticles were introduced to construct micro/nano-structures, and finally, surface modification with polydimethylsiloxane (PDMS) was carried out to prepare superhydrophobic films. The surface of the superhydrophobic film had a micro/nano-scale structure similar to that of lotus leaves. The water contact angle (WCA) of superhydrophobic films reached 153°, and sliding contact angle (SA) was 5°. Owing to this unique structure, different liquid food droplets could roll off freely in a near spherical form on the chitosan phytate film surfaces, effectively reducing residue during container pouring. The outcomes of this study are expected to expand the potential applications of superhydrophobic chitosan films in liquid food anti-adhesion.