Green hydrophilic capsules from CNC-stabilized Pickering emulsion polymerization: morphology control and sponge-like behavior

International audiencePickering inverse emulsions of hydroxyl oligoethylene glycol methacrylate were stabilized in isopropyl myristate, a bio-friendly oil, using surface-modified cellulose nanocrystals (CNCs) as stabilizing particles. The emulsions were further polymerized by whether free or controlled radical polymerization (ATRP) taking advantage of the bromoisobutyrate functions grafted on the CNC surface. Suspension polymerization of the emulsion led to full beads or empty capsules morphologies depending on the initiation locus. Thickness of the CNC shell surrounding the polymerized emulsions could be tuned by modulating the aggregation state of the CNCs after their surface modification. An increase from 6 to 40 CNC layers helped improve the compression moduli of the beads from a dozen to hundreds of kPa