Metal-Free and Carbon-Free Flexible Self-Supporting Thin Film Electrodes

Abstract

Conductive polymers are promising for application in the medical and sport sectors, e.g. for thin wearable health monitoring systems. While many today’s electrodes contain either carbon or metals as electrically conductive filler materials, product design manufacturing has an increasing interest in the development of metal free and carbon free, purely polymer based electrode materials. While conducting polymers have generally rather low electrical conductivities compared to metals or carbon, they offer broad options for industrial processing, as well as for dedicated adjustments of final product properties and design aspect, such as colour, water repellence, or mechanical flexibility in addition to their electrical properties. The development of electrically conducting polymer blends, based on conductive polymers is thus timely and of high importance for the design of new attractive flexible electrodes. We have developed material formulation and processing techniques for the fabrication of self-supporting thin film electrodes based on polyaniline (PANI) and polyvinylidene fluoride (PVDF) blends. Electrical four-point probing was used to evaluate the electrode conductivity for different processing and fabrication techniques. Optical microscopy and atomic force microscopy measurements corroborate the observed electrical conductivity obtained even at low PANI concentrations revealing the nanoscale material distribution within the blends. Our self-supporting thin film electrodes are flexible, smooth, and water repellent and were furthermore successfully tested under bending and upon storage over a period of several months. This opens new perspectives for the design of metal free and carbon free flexible electrodes for medical, health, and sports applications.