In Situ Formation of Autodispersing Cellulose Nanoparticles with Extreme Uniformity

Autodispersing cellulose nanospheres with a uniform diameter of 20 nm were prepared via self-assembly of cellulose chains with controlled molar masses in an ionic liquid. To obtain nanospheres, cellulose was dissolved in 1-butyl-3-methylimidazolium chloride and then precipitated in deionized water. During dissolution, positive charges were induced at the reducing ends of cellulose by the reaction with the imidazolium. The reaction was more active when the molar mass was smaller than 100 kg·mol^-1. As the molar mass decreased, the surface charge originating from the imidazolium increased, resulting in a stable dispersion in aqueous media. The increase of the surface charge also improved the crystallinity and the uniformity of the size dramatically.