Development of electromechanical properties of biocompatible gelatin as actuator application

Abstract

Nanowire-Polypyrrole/gelatin. MWNT/gelatin, and graphene/gelatin hydrogel composites were fabricated by the dispersion of Nano fillers into the gelatin aqueous solution followed by the solvent casting. The electromechanical properties, thermal properties and deflection of pure gelatin hydrogel and nanowire- polypyrrole/gelatin, MWNT/gelatin, and graphene/gelatin hydrogel composites were studied as functions of temperature, frequency, and electric field strength as an actuator. The 0.01, 0.1, 0.5. 1 vol% these hydrogel composites and pure gelatin hydrogel possess a higher storage modulus sensitivity values (∆Ǵ/Ǵo) at a higher applied electric field strength in which graphene/gelatin hydrogel composites exhibit the greatest (∆Ǵ/Ǵo suggesting that it is the most suitable candidate for actuator applications. Nevertheless, the stress relaxation behavior as an important property for actuator. Uncross linked and cross linked gelatin hydrogels were prepared by adding a glutaraldehyde solution into a gelatin solution followed by a casting method. Stress relaxation functions of the uncross linked and cross linked gelatin hydrogels were measured to study the effects of electric field strength and the crosslinking ratio. For the uncross linked. 3 vol% cross linked and 7 vol% cross linked gelatin hydrogels, the relaxation times decrease with increasing degrees of crosslinking and the applied electric field strengths. The experimental shift factors can be thus obtained from either the stress relaxation functions or the storage and loss moduli. Both approaches yield numerically the same shift factor values which successfully allow the time- electric field superposition of various related functions.