Dielectric polarization enhancement of thermoplastic elastomers for sensing and energy harvesting applications.

Abstract

Nano-structured dielectric thermoplastic elastomers (DTEs) such as poly(styrene-co-ethylene-co-butylene-styrene) [SEBS] and poly(styrene-co-ethylene-co-butylene-styrene) –grafted- maleic anhydride[SEBS-g-MA] triblock co-polymers have been shown to have superior mechanical performances relative to conventional dielectric elastomers such as silicones because of their morphology; which comprises of continuous hard and soft block copolymers and physical cross-linking between same. However, historically their use in capacitive energy harvesting and sensing applications has been constrained by their relatively low dielectric permittivity. In this work, novel method for increasing the dielectric permittivity of DTE’s while maintaining their mechanical performance by using electrically active modifiers was evaluated. Preliminary results showed a 110% and 99% increase in the dielectric permittivity, and a 787% and 300% increase in the storage modulus, of SEBS and SEBS-g-MA respectively upon addition of 10% carbon black. The storage modulus will be decreased if the materials are pre-strained. These results also indicate that relative changes in the electrical properties of polymer-additive composites is polymer-additive compatibility dependent (i.e. 1.20% decrease in the dielectric permittivity of SEBS and a 32.72% increase in the dielectric permittivity of SEBS-g-MA was observed upon addition of 10% BaTiO3).