Novel polymeric elastomers for actuation

Abstract

Efficient actuators that are lightweight, high performance and compact are needed to support telerobotic requirements for future NASA missions. A new class of electrostrictive polymeric materials has been developed in our recent work. The materials are graft elastomers that exhibit not only large electric field-induced strain (4%) but also a relatively high mechanical modulus (560 MPa). Consequently, the materials offer high actuation output power for enhanced actuation performance. In addition to the promising electromechanical properties, the materials are readily processable by conventional methods. By combining this graft elastomer with a piezoelectric polymer, polyvinylidene fluoride (PVDF), an electrostrictive-piezoelectric multifunctional polymer blend system has also been developed. This multifunctional system exhibits a significantly high piezoelectric strain coefficient, d/sub 31/, of 12 pC/N while the electric field-induced strain is enhanced due to the combination of the mechanisms of electrostriction and piezoelectricity. Experimental results of the electric field-induced strain in the polymeric elastomers and the electrostrictive-piezoelectric polymer blend system are discussed. A prototype bending actuator using the materials is also presented.