Highly stretchable and conductive polymer material made from poly (3,4-ethylenedioxythiophene) and polyurethane elastomers

A highly elastic and stretchable conductive polymer material resulted from blending the conductive polymer poly(3,4-ethylenedioxythiophene).p-tosylate and an aliphatic polyurethane elastomer. The blend inherited advantageous properties from its constituents, namely high conductivity of 120 S cm(-1) from its conductive polymer component, and elastomeric mechanical properties resembling those of the polyurethane, including good adhesion to various substrates. Stretching of the blend material by up to 50 % resulted in increased conductivity, while subsequent relaxation to the unstretched state caused a decrease of conductivity compared to the pristine blend. These initial changes in conductivity were reproducible on further cycling between 50 % stretching and the unstretched state for at least 10 cycles. Stretching beyond 50 % resulted in decreasing conductivity of the blend but with substantial conductivity remaining even when stretched by 200 %. Optical, mechanical, and thermal properties of the blend, as well as high resolution electron microscopy of bulk cross-sections, suggest that the system is a single phase and not two separate phases. Ageing experiments indicate that the material retains substantial conductivity for at least a few years at room temperature.