Multilayer assemblies of cellulose nanocrystal - polyvinyl alcohol films featuring excellent physical integrity and multi-functional properties

A simplistic approach to cellulose nanocrystals (CNCs) percolation at low concentrations with multifold increases in properties, through the development of multilayered film assemblies was employed. CNC networks combined with polyvinyl alcohol (PVOH) thin films were fabricated leading to multilayer assembly of randomly aligned CNC nanorod bundles, similar to those found in biological structures. Oxygen impermeable barrier property of the films was achieved. The optical clarity remained mostly pristine while exhibiting improved UV absorbance. These films can be applied towards shielding UV sensitive materials that require optical transparency. A 415 and 2300% increase in strength and modulus, respectively, were observed for multilayered film with 10 wt% CNC loading as compared to the baseline neat PVOH film. The multilayers and networks formed through strong hydrogen bonds and structural alignment of the CNCs make this strategy effective in achieving enhanced properties at low CNCs loadings, which can be applied to other polymer films with property limitations. (C) 2020 Elsevier Inc. All rights reserved.