Performance evaluation of bending actuators made from electrostrictive graft elastomers

Recently a new class of electrostrictive polymers, called electrostrictive graft elastomers, was developed at NASA Langley Research Center. In this work, the output force of a bending actuator made from electrostrictive graft elastomer was measured and modeled to understand the dependence of performance on device configuration. This understanding should lead to better actuator design and fabrication. The prototype bending actuator is 47 gm thick and 8 mm wide. The output bending force at the tip was measured as a function of applied voltage and the distance from the tip to the holding stage. The output force at 2.1 kV increases from 124 muN at a length of 33.5 min to 662 muN at 7 mm. According to a small displacement, 5-layer, strength-of-materials model, the output bending force of the actuator varies inversely with its length and directly with the square of the applied voltage. Consequently, the output bending force can be about 5 mN when the length of the actuator is reduced to 1 mm for application to micro-electromechanical (MEMS) devices. The experimental results will be presented and a method for enhancing the performance will also be discussed.