• Mckee, Jason R.
• Majoinen, Johanna
• Walther, Andreas
• Kontturi, Eero
• Ikkala, Olli.
• Aseyev, Vladimir O.
• Malho, Jani Markus
• Ruokolainen, Janne

Abstract

Herein we report the synthesis of cellulose nanocrystals (CNCs) grafted with poly(acrylic acid) (PAA) chains of different lengths using Cu-mediated surface initiated-controlled radical polymn. (SI-CRP).First, poly(tert-butylacrylate) (PtBA) brushes were synthesized; then, subsequent acid hydrolysis was used to furnish PAA brushes tethered onto the CNC surfaces.The CNCs were chem. modified to create initiator moieties on the CNC surfaces using chem. vapor deposition (CVD) and continued in solvent phase in DMF.A d. of initiator groups of 4.6 bromine ester groups/nm2 on the CNC surface was reached, suggesting a dense functionalization and a promising starting point for the controlled/living radical polymn.The SI-CRP of tert-butylacrylate proceeded in a well-controlled manner with the aid of added sacrificial initiator, yielding polymer brushes with polydispersity values typically well below 1.12.We calcd. the polymer brush grafting d. to almost 0.3 chains/nm2, corresponding to high grafting densities and dense polymer brush formation on the nanocrystals.Successful rapid acid hydrolysis to remove the tert-Bu groups yielded pH-responsive PAA-polyelectrolyte brushes bound to the CNC surface.Individually dispersed rod-like nanoparticles with brushes of PtBA or PAA were clearly visualized by AFM and TEM imaging. [on SciFinder(R)]

Topics

• nanoparticle
• surface
• polymer
• phase
• atomic force microscopy
• transmission electron microscopy
• cellulose
• functionalization
• ester
• chemical vapor deposition
• polydispersity