Nanocellulose-based superhydrophobic coating with acid resistance and fluorescence

A nanocellulose-based multiple-functional coating was fabricated with excellent superhydrophobicity, abrasion resistance, acid resistance and fluorescence. The fluorescent cellulose nanofibril (FCNF) prepared by grafting 5-(4,6-dichlorotriazinyl) aminofluorescein (DTAF) onto CNF was used to construct the 2–8 μm microparticles with many gullies by spray drying, which were hydrophobically modified by MTMS. A superhydrophobic coating was formed by combining the MTMS-modified microparticles and polydimethylsilane (PDMS), and coated on filter paper and wood block. The coated paper and the wood block had the water contact angles (WCA) 156.6° and 162° with sliding angle <10°. The coating layers remain superhydrophobic after being immersed in hydrochloric acid solution of pH 1, 4, and 0.1 M NaCl solution for 4 h. In addition, the obtained coating possessed excellent friction resistance, which remained the WCA of 150.8° after 50 frictions with 200 g weight. The good folding and crimping resistance, self-cleaning and acid corrosion resistance properties were reported as well. Interestingly, this fluorescent superhydrophobic coating is promising to be implemented as outer building materials to prevent acid corrosion, luminous decorative materials and anti-counterfeiting materials.