Strong, transparent cellulose film as gas barrier constructed via water evaporation induced dense packing

A simple strategy of water evaporation induced dense packing is used to construct regenerate cellulose film (CF) with high strength and transparency. Cellulose solution was cast and exposed to atmosphere at room temperature to conduct water evaporation, and it was concentrated and undergoes a sol-gel transition to form a physically cross-linked network with high packing density. CFs were obtained after removing the residue solvent. The dense packing led to homogeneous structure and decreased pore size, as well as enhanced mechanical, optical and gas barrier property. The highest tensile strength reached 158.2 and 11.7 MPa in the dry and hydrogel state, respectively, stronger than regenerated cellulose films of same kind, while the visible light transmittance at 550 nm reached 89.94 and 95.05% in the dry and hydrogel state. O-2 and CO2 permeability at 40% relative humidity reached 1.37 x 10(-17) and 1.08 x 10(-17) cm(3) cm cm(-2) s(-1) Pa-1, respectively, lower than literatures in the same condition. Moreover, cellulose/silver nanocomposite was fabricated by taking advantage of the mechanical and optical property of CF, demonstrating a considerably low detection limit and high sensitivity as optical sensing platform. The present work supplies a simple pathway to improve the structure and property of regenerated cellulose materials, demonstrating great potentials.