Preparation of Food Grade Superhydrophobic Coatings Based on Attapulgite Nanorods

The superhydrophobic coating is a promising strategy to avoid liquid foods adhesion on the packages and thus significantly reduce their waste and environmental pollution. However, food-grade superhydrophobic coatings are yet limited, especially those with excellent performances. Herein, we report the preparation of food-grade superhydrophobic coatings by the combination of attapulgite (APT) natural nanorods, stearic acid (STA), and hydroxypropyl distarch phosphate (HDP) adhesive. First, a stock suspension was prepared by an esterification reaction between APT and STA. Then, the edible HDP primer and the STA@APT suspension were sequentially spray-coated onto substrates to form the HDP/STA@APT superhydrophobic coatings. The influences of the STA and APT concentrations on the wettability and morphology of the coatings were studied. Due to the hierarchical structure and low surface energy of the coatings assembled by APT and STA, the coatings show excellent static and dynamic superhydrophobicity and self-cleaning performance. In addition, the coatings exhibit good environmental stability and excellent antiadhesive properties toward various liquid foods and are also applicable to various frequently used food packing materials. Thus, we believe that superhydrophobic coatings have a broad application prospect for food packing.