Dielectric and Resistive Heating of Polymeric Media: Toward Remote Thermal Activation of Stimuli-Responsive Soft Materials.

Abstract

Stimuli-responsive soft materials are becoming increasingly important in a wide range of contemporary technologies, and methods by which to promote thermal stimulation remotely are of considerable interest for controllable device deployment, particularly in inaccessible environments such as outer space. Until now, remote thermal stimulation of responsive polymers has relied extensively on the use of nanocomposites wherein embedded nanoparticles/structures are selectively targeted for heating purposes. In this study, an alternative remote-heating mechanism demonstrates that the dielectric and resistive thermal losses introduced upon application of an alternating current generate sufficient heat to raise the temperature of a neat polyimide by over 70°C within ≈10s. Thermal imaging is used here to measure current-induced temperature changes of polymeric media, and a proposed analytical model yields predictions that compare reasonably well with experimental data, confirming that such remote heating is viable. Conditions permitting a shape-memory polymer possessing a melting transition and susceptible to dielectric actuation to achieve continuous electrostrain-temperature cycling are identified.