Multiple crosslinked alkyl ketene dimer-based superhydrophobic coating for structurally robust waterproof cellulosic paper

Abstract

The instability of traditional superhydrophobic coating severely restricted the practical application of cellulosic paper in our daily life. Herein, a sort of novel structurally robust waterproof cellulosic paper was elaborately designed via the facile coating alkyl ketene dimer (AKD)/dodecyltrimethoxysilane (DTMS)/silica nanoparticle dispersion (SiO₂). Originating from the coupling reaction between DTMS and SiO₂ and the adsorption of DTMS on AKD emulsion latex, the growth direction of AKD was regulated and AKD/DTMS/SiO₂ coating layer was formed. The outermost SiO₂ with relatively dense structure effectively prevent the permeation of moisture into the inside of coating. During 20∼160 °C, the coated paper still remained highly superhydrophobic surface with water contact angle (WCA) >160°. Moreover, the inorganic SiO₂ layer endowed the superhydrophobic paper with satisfied chemical and mechanical stability. Various beverages (e.g. milk, yogurt, honey and other edible liquids) could not be adhered onto the surface of superhydrophobic paper, indicating the great potential application as packaging materials. Our findings not only provided a new perspective to design the structurally robust superhydrophobic coating, but also boosted the application of cellulosic fibers in food packaging to replace traditional plastic.