Effect of solvent mixture on properties and performance of electro-active paper made with regenerated cellulose

Cellulose can be regenerated by dissolving cellulose fibers using LiCl/N,N-dimethylacetamide (DMAc) solvent system, and by curing the cellulose solution with deionized (DI) water. This regenerated cellulose has been discovered as a new smart material, termed as electro-active paper (EAPap). However, Li+ ions and DMAc solvent were partially entrapped in the cellulose matrix upon curing, resulting in negative effects on the surface morphology, mechanical properties and the bending actuator performance of EAPap. In the present study, we made an attempt to remove the ions and solvents by curing the regenerated cellulose films with DI water and isopropyl alcohol (IPA) solvent mixture. Characteristics of cellulose films with different solvent mixture ratios were investigated by SEM, TGA, AFM, ICP-MS and tensile test, and the durability of cellulose EAPap actuator was studied by measuring the bending displacement of the actuator. An optimum solvent mixture ratio was suggested, which showed an improvement in terms of the surface roughness, Young's modulus as well as the durability of cellulose EAPap actuator.