Silicone-based Carbon Black Composite for Epidermal Electrodes

Abstract: A method of synthesizing silicone-based composite consisting of carbon black (CB) as a conductive ller in Polydimethylsiloxane (PDMS) was developed. The aim was to nd a cost eective and easier method to fabricate stretchable, epidermal and conductive electrodes in striving for inexpensive real-time health monitoring. In this work, instead of expensive additive materials for enhancement of PDMS conductivity, CB powder, at lower cost was used. To optimize the electrophysiological properties of the electrodes, limited amount of silver (Ag) and silver chloride (AgCl) particles were added. The electrical characteristic of the electrodes and their stretchability was studied. Since fabrication and characterization did not require clean room enviroment, the developed method was less costly and less time consuming. Samples were made of six dierent ller concentrations in three sets, which in total were 18 samples, in order to obtain better statistics. Resistance of all samples was measured and resistivity values were calculated. Tensile test were performed on all samples. The result showed that all samples had elongation of over 50 %, which is feasible for stretchable, epidermal patches. Samples with ller concentration of 10 wt% CB + 5 wt% Ag/AgCl and 10 wt% CB + 8 wt% Ag/AgCl showed resistivity of Wcm range. The electrodes were conductive, soft, stretchable and biocompatible. They fulll the requirements of epidermal patches for health monitoring.