Amorphous cellulose thin films

Amorphous cellulose thin films with thicknesses of 8-100 nm and sub-nanometer roughness have been fabricated by spin-casting from molecular solutions of cellulose in mixtures of ionic liquids and organic solvents. Combining X-ray, optical and scanning probe measurements, cellulose films have been found to be fully amorphous, and their mass densities are comparable to that of the bulk amorphous cellulose. Full amorphization of cellulose films is achieved through sequential removal of solvents, successive diffusion of ionic liquid molecules out of cellulose films, and simultaneous formation of hydrogen bonding among cellulose chains. [GRAPHICS] .