High-strength, transparent and superhydrophobic nanocellulose/nanochitin membranes fabricated via crosslinking of nanofibers and coating F-SiO2 suspensions

In this study, nanocellulose/nanochitin membranes were prepared by suction filtrating 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized cellulose nanofiber (TOCNF)/partially deacetylated α-chitin nanofiber (α-DECHN) mixed suspensions. The result shows that, with a 1:1 ratio of nanocellulose to nanochitin, the tensile strength of the obtained composite membrane reaches 115.7 MPa and its light transmittance is 77.6 %. Heptadecafluoro-1,1,2,2-tetrahydrodecyl dimethylchlorosilane (HFTD) modified nano SiO2 (F-SiO2), was utilized to construct rough micro/nanostructures on the surfaces of the composite membranes by screen printing, forming high-strength, transparent and superhydrophobic nanocellulose/nanochitin membranes. Atomic force microscope (AFM) images reveal that nanocellulose and nanochitin, with the width between 5 nm and 20 nm and the length between 400 nm and 1.1 μm, are crosslinked with each other. The superhydrophobic nanocellulose/nanochitin composite membranes functionalized with a 2.0 wt% F-SiO2 suspension has a few clusters on its surface. The contact angle of this membrane is 150.1°, and its light transmittance is 70.4 %.