The origins of electromechanical response in polyurethane elastomers

Electric-field-induced strains of polyurethane elastomers have been measured. The mechanical constrains and flexure motion of the samples which can cause large experimental error were excluded from the measured strain signals. The longitudinal and transverse strain coefficients are evaluated as functions of frequency. The dielectric and elastic properties and their temperature and frequency dependencies have also been studied. The experimental results show that strain larger than 2% can be obtained and that the sample processing conditions can affect the strain level. The contributions from Maxwell stress effect and electrostriction to the strain responses are examined. The results suggest that Maxwell stress effect plays an important role in electromechanical response of the materials