This paper presents an approach towards realising novel multifunctional polymer composites. A series of structural capacitor materials made from carbon fibre reinforced polymers have been developed, manufactured and tested. The capacitors were made using three thicknesses of DuPont Mylar A thermoplastic PET as dielectric separator employing carbon fibre/epoxy pre-pregs as structural electrodes. Plasma treatment was used as a route for improved epoxy/PET adhesion employing a number of treatment times, 5, 10, 15, 20 and 25s. The manufactured materials have been mechanically and electrically tested to evaluate their multifunctional efficiency. Plasma treatment have been shown to give some improvements to the interlaminate shear strength but not to any significant degree.