Cellulose Nanocrystals in Spherical Titania-Sol Microdroplet: From Dynamic Self-Assembly to Nanostructured TiO x /C Microsphere Synthesis

The study and control of cellulose nanocrystals (CNCs) self-assembly in spherical confinement remains a challenging and unexplored area. It is difficult to directly observe the self-organization of CNCs in such geometry. Herein, a dynamic observation of the self-organization process of CNCs in confined titania-sol microdroplet is reported. The isotropic-to-cholesteric transition undergoes nucleation, coalescence, and migration of tactoids through two coalescence mechanisms, namely, “head-to-tail” and “side-to-side” types. The solubility and self-organization of CNCs in titania-sol enable a successful transfer of the chiral (Ch) nematic structure into hybrid TiO x /C microspheres. TiO x /C microspheres show higher photocatalytic H 2 generation compared to TiO 2 -P25. This work adds to the understanding of self-assembly process of CNCs in spherical geometry and provides a fresh avenue to design nanostructured photoactive microspheres with unique Ch nematic structures.