纖維素奈米微晶定向薄片壓電性質之改進與評估

Abstract

An actuator is a mechanism for converting energy into motion. Piezoelectric actuators displace themselves when electric field is applied. Piezoelectric elements are lightweight and highly responsive, but the problem is that displacement is small with respect to changes in the electric field. Recently, high piezoelectric polymer materials have been developed and practically used as actuators. Biopolymer actuators are expected to expand their application in fields such as agricultural land and forest land utilizing biodegradability. Therefore, using nanocellulose with high crystallinity as a piezoelectric material was evaluated. The purpose of this thesis is to measure fundamental piezoelectric and inverse piezoelectric properties and to measure how these properties of cellulose nanocrystals, representative nanocellulose, are changed with blending cellulose nanofibers. In Chapter 5, Physical properties are compared based on the difference in the blending ratio between CNF and CNC. As the ratio of CNF increased, the tensile strength tended to increase. In Chapter 6, the piezoelectric coefficient of the CNF/CNC film and polyvinylidene difluoride (PVDF) film with high piezoelectricity were compared in the voltage generated by applying force and displacement by applied electric field. Although CNF/CNC films had much lower piezoelectric constants than that of the PVDF film; however, showed certain levels of piezoelectric constants, and no difference in piezoelectricity due to the difference in blending ratio of CNF/CNC was found. In Chapter 7, the piezoelectric coefficient was measured by using scanning probe microscope. The piezoelectric coefficient of the CNF/CNC film was influenced by the density rather than the blending ratio of CNF/CNC. In Chapter 8, CNF/CNC film is prepared by using electrospinning in order to control orientation.