Emergent hybrid mesophases in ternary mixtures of cellulose nanocrystals - Pluronic micelles-water

Mixtures of nanometric rods and spherical micelles that are dominated by excluded volume (entropic) interactions tend to de-mix into sphere- and rod-rich mesophases. Here we report the observation of hybrid mesophases formed by mixtures of polymer-decorated sulfuric-acid-hydrolyzed cellulose nanocrystals (CNCs, rod-like particles), at high CNCs concentrations (7 wt%) where the native CNCs suspensions are at the bi-phasic (isotropic-chiral nematic) regime, and spherical micelles of the tri-block-copolymers Pluronic F127 (and F108) in aqueous suspension. The polymers adsorb onto the CNCs particles, and at F127 concentrations above (10–18 wt%) the macroscopic phases of the hybrid mixture are transformed into mesoscopic droplets with a nanostructure that differs from that of the CNCs or the native Pluronics, as indicated by small-angle X-ray scattering. The observed phases preserve the chiral nematic nature of the CNCs phases with a shortened pitch, suggesting that co-assembly of CNCs and self-assembling polymers may be used for engineering of emergent phases with emergent structures and properties.