Physicochemical properties of cellulose nanocrystals treated by photo-initiated chemical vapour deposition (PICVD)

Cellulose nanocrystals (CNCs) are novel nanomaterials produced by the pulp and paper industry. The surface properties of CNCs are key factors for their dispersion in solvents. These polar materials disperse readily in water, but not in organic solvents. The ability to disperse into typically non-polar organic matrices is an indispensable requirement to exploit the growing market for nanocomposite materials. We present an innovative approach for modifying the surface of CNCs through scalable, gas-phase photo-initiated chemical vapour deposition (PICVD). Using syngas as a treatment precursor, we demonstrate the effectiveness of this technique to render the surface of the CNCs compatible with mildly polar and non-polar solvents, evidenced by contact angle measurements. Further proof of this successful modification is given through dispersion assays, showing for example the ability to disperse treated CNC in toluene (whereas untreated samples do not disperse). Suspensions in organic solvents remain stable in excess of two weeks. Chemical characterization through XPS and FTIR confirms the presence of an oxygen-containing coating on the CNC surface.

Mots clés

PICVD; photochemistry; cellulose nanocrystals; contact angle; FTIR; TEM; XPS