Role of solvent on structure, viscoelasticity, and mechanical compressibility in nanocellulose-reinforced poly(vinyl alcohol) hydrogels

Cellulose nanocrystals (CNCs) reinforced polyvinyl alcohol (PVA)-based hydrogels with high water content and tunable mechanical properties that can be molded in to any desired shape are presented in this work. Freeze thawing of PVA-CNC solutions in a mixed solvent system of dimethyl sulfoxide and water enabled to produce a set of physically crosslinked hydrogels with tunable mechanical properties. It was observed that the composition of the solvent altered the mechanical properties and network structure in the hydrogel systems. Differential scanning calorimetry was used to understand the thermal events behind solvent effect on the properties of the hydrogel. Optical microscopy results suggest that these hydrogels possess a macroporous structure. Furthermore, dynamic viscoelastic analysis and axial compression tests have shown that the viscoelastic and mechanical compression properties of the hydrogels improved upon reinforcement with CNC. Overall, the hydrogel enjoys appealing properties as a synthetic biomaterial for soft tissue applications. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47044.