Preparation of spherical microparticles composed of cellulose nanofiber and cellulose diacetate via Pickering emulsion templating

Cellulose nanofiber (CNF) derived from woody bioresources is a fascinating natural nanomaterial. In this work, spherical microparticles were fabricated by using TEMPO-oxidized CNF (TOCNF) and cellulose diacetate (CDA) via Pickering emulsion templating. The CDA-dissolved organic solvents were emulsified stably with TOCNF, followed by removing the solvents to form microspheres with core-shell structures, where the CDA cores were covered with the TOCNF shells. The prepared spherical microparticles possessed an average diameter and sphericity index of 6.4 μm and 0.96, respectively. The zeta-potential value was approximately -48 mV, indicating the stable colloidal system in water. The CDA/TOCNF microparticles were stained with toluidine blue dye for negatively-charged TOCNF. Besides, furry nanofiber-like morphology was observed on the particle surface by scanning electron microscopy. Wood-derived CDA/TOCNF microspheres are a promising alternative to fossil resource-derived, non-biodegradable microbeads in cosmetic applications.