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Electrostrictive response in polyurethane films containing lithium ionic impurities

I. DIACONU1,* , D. DOROHOI2

Affiliation

  1. Medical Bioengineering Dept. of University of Medicine and Pharmacy, Iasi, Romania
  2. Faculty of Physics, Al.I. Cuza Univesity, Iasi, Romania

Abstract

The influence of the added lithium ions on the electromechanical response in the unelectroded films of polyurethane based on poly(caprolactone)diol, 1,4-butane diol and isofuran diisocyanate under static electric field was investigated. Longitudinal strain, stress-strain and dielectric measurements were carried out on films with various thicknesses under ambient conditions. On the basis of these measurements the electromechanical parameters such as thickness strain, apparent electrostrictive coefficient, effective pressure, mechanical energy density, response time and Maxwell effect contribution were determined. Induced strain depended quadratically on the electric field, which is consistent with an electrostrictive response. The induced strain increases with film thickness tending to reach a plateau for higher values. As compared to the original samples (no added ions), the added lithium ions enhance the strain response only in films thicker than about 50 μm. The electromechanical parameters are improved in the same thickness domain. The results show that addition of lithium ions can improve the actuation performances of the polyurethane investigated..

Keywords

Polyurethane elastomer, Electrostatic thickness strain, Electromechanical parameters, Lithium ions.

Submitted at: Nov. 2, 2006
Accepted at: April 15, 2007

Citation

I. DIACONU, D. DOROHOI, Electrostrictive response in polyurethane films containing lithium ionic impurities, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 4, pp. 990-993 (2007)