Electrostriction of a Polyurethane Elastomer-Based Polyester

Abstract

This paper is dealing with the electromechanical properties of a synthesized polyurethane elastomer film-based polyester. On the basis of the electrostatic-field induced strain, dielectric, and stress-strain measurements carried out under ambient conditions, the electromechanical parameters such as thickness strain, apparent electrostrictive coefficient, effective pressure, mechanical energy density, and Maxwell-effect contribution, were determined. Thickness strain versus the static electric field showed a quadratic dependence up to about 6.3 MV/m, which is consistent with an electrostrictive response. The maximum induced strain of 7% obtained at 16 MV/m is higher than those reported in the literature on unprestrained polyurethane film with noncompliant electrodes. Remarkable apparent electrostrictive coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(sim 7.75 10^-16 hboxm^2/hboxV^2)$</tex> and response time (600 ms) were found. Under the actual experimental conditions (rigid electrodes and maximum electrostatic field of 16 MV/m), the effective compressive pressure (0.9 MPa) and mechanical energy density (0.032 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$hboxJ/cm^3$</tex> ) values are quite noticeable. A small Maxwell-effect contribution of only 0.32% was found. The electromechanical parameters of this polyurethane elastomer indicate that this material is potentially useful for practical actuators and sensors.