Electrically aligned cellulose film for electro-active paper and its piezoelectricity

Abstract

Electrically aligned regenerated cellulose films were fabricated and the effect ofapplied electric field was investigated for the piezoelectricity of electro-active paper(EAPap). The EAPap was fabricated by coating gold electrodes on both sides ofregenerated cellulose film. The cellulose film was prepared by dissolving cotton pulp inLiCl/N,N-dimethylacetamide solution followed by a cellulose chain regeneration process. Duringthe regeneration process an external electric field was applied in the direction ofmechanical stretching. Alignment of cellulose fiber chains was investigated as afunction of applied electric field. The material characteristics of the cellulosefilms were analyzed by using an x-ray diffractometer, a field emission scanningelectron microscope and a high voltage electron microscope. The application ofexternal electric fields was found to induce formation of nanofibers in the cellulose,resulting in an increase in the crystallinity index (CI) values. It was also foundthat samples with higher CI values showed higher in-plane piezoelectric constant,d31, values. The piezoelectricity of the current EAPap films was measured to be equivalent orbetter than that of ordinary PVDF films. Therefore, an external electric field applied to acellulose film along with a mechanical stretching during the regeneration process canenhance the piezoelectricity.