Cellulose nanocrystals (CNCs) are "green", biocompatible and renewable nanoparticles which have intermediate hydrophilicity and favourable mechanical properties. Their interaction with water and solvents remains poorly understood but is of fundamental importance for nanoparticle coatings and cellulose-based materials. This work explores thin film swelling and CNC particle–particle interactions by investigating model cellulose films in aqueous solutions (with high and low concentrations of sodium chloride and calcium chloride) and organic solvents (methanol, acetonitrile, ethanol, acetone and isopropanol). CNC film thickness and solvent uptake were monitored continuously throughout swelling via surface plasmon resonance spectroscopy and kinetics of liquid uptake and diffusion were characterized. CNC films with different surface charge densities were evaluated to better understand the contribution of electrostatic double layer forces on film swelling. Solvents which possess significant hydrogen bonding and polar components were observed to interrupt cohesive interparticle interactions the most, however CNC films remained stable throughout the swelling measurements demonstrating that solvation in all tested media is insufficient to overcome van der Waals forces.<br/>

Swelling of cellulose nanocrystal thin films in solvents and aqueous solutions

251st National Meeting (2016)

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