Chitosan/acrylic rosin-based superhydrophobic coatings inspired by Pickering emulsion template and lotus leaf surface...

The superhydrophobic coated papers have attracted much attention as the promising alternatives for disposable plastic packaging materials in food packaging fields. Despite recent visible progress in constructing superhydrophobic coated papers, it is still a challenge to realize superhydrophobicity, high oil-resistant behavior, biodegradability and recyclability at the same time in a coated paper. Herein, we have effectively constructed the superhydrophobic coated (PE&SP-CP) paper with the imitated lotus leaf surface structures by firstly dip-coating cellulose nanocrystals stabilized Pickering emulsion containing chitosan in water phase and acrylic rosin (AAR) in oil phase, and then spraying ethanol suspension of hydrophobic nano-silica (hSiO₂) and polydimethylsiloxane (PDMS). In this aspect, the micro-nano hierarchical surface of chitosan-based coating film consists of AAR microcapsules and hSiO₂ nanoparticles, as well as covered a hydrophobic PDMS polymer layer. And the prepared PE&SP-CP paper with surface superhydrophobicity demonstrates the highly water barrier performance with the water contact angle of 155.8° and water vapor permeability rate of 1.42 × 10^-10 gm^-1s^-1Pa^-1, the favorable oil repellency with the kit rating of 9/12, the clearly improved tensile strengths of 21.67 MPa. Interestingly, the PE&SP-CP paper also shows superior antifouling performance, self-cleaning ability, biodegradability of soil burial and recyclability. This work provides a universal approach for the effective construction of oil-resistant, self-cleaning, antifouling, recyclable, biodegradable superhydrophobic coated paper with the imitated lotus leaf surface structure, which has great potential application in the food packaging industry.