Functional cellulose nanocrystals containing cationic and thermo-responsive polymer brushes

Cationic and thermo-responsive polymer brushes were grafted from the surface of cellulose nanocrystals. Di (ethylene glycol) methyl ether methacrylate (MEO(2)MA) and poly(oligoethylene glycol) methyl ether acrylate (OEGMA300) and (2-methacryloyloxyethyl) trimethylammonium chloride (DMC) were grafted from cellulose nanocrystals (CNCs) via free radical polymerization. The CNC-g-POEGMA (CP) possessed a tunable lower critical solution temperature (LCST) of about 50 degrees C, and cloud point measurements confirmed that the LCST of the nanoparticles could be manipulated within the range of 40-47 degrees C by adjusting the DMC content. The salt effect was also investigated, and the results revealed a typical salting-out effect for the CNC-g-POEGMA after the introduction of KCl. On the other hand, the CNC-g-POEGMA-g-DMC (CPD) copolymers displayed two salt -re-sponsive characteristics; polyelectrolyte effect at lower salt concentrations, followed by the salting-out effect at higher salt concentrations, which is dependent on the DMC content.