Functionalised carbon nanotubes loaded polyurethane dielectric elastomer for transduction.

Dielectric elastomers, thanks to their particular dielectric and mechanical properties, have recently been the focus of several works regarding electromechanical transduction. Silicones, polyurethanes and acrylic elastomers are, in fact, the main representatives of electronic polymers for transduction among the broad class of electro-active polymers. In order to be employed as materials for actuation, however, they have to show high dielectric constant, low elastic modulus and, possibly, restrained dielectric and mechanical losses, so to maintain high dielectric strengths and allow large deformations. In this work, for the first time, a study on the effects of loading of an elastomeric polyurethane with covalent functionalized carbon nanotubes (FCNTs), is presented. The obtained composites have been dielectrically, mechanically and electromechanically characterized and the properties observed have been compared with those showed by composites containing the same fractions of pristine carbon nanotubes as filler. The values of actuation strains showed by some of the prepared systems drive to the conclusion that an effective increase in the electromechanical performance is possible by using FCNTs as filler and open the way for future investigations.