Flexible dry electrode based on carbon nanotube/polymer hybrid micropillars for biopotential recording

A novel flexible dry electrode based on carbon nanotube (CNT) and polydimethylsiloxane (PDMS) is proposed for recording biopotentials. Because the homogeneous dispersion of CNTs in PDMS is challenge due to the high viscosity of PDMS and aggregation of CNTs, a novel process is developed through addition of an organic solvent to disentangle CNTs and reduce the viscosity of PDMS. The electrical performance of the composite of CNTs and PDMS as the function of CNT concentration was characterized. The optimized 10 wt% MWCNTs is dispersed in PDMS as the material of flexible dry electrode. In order to apply for long-term, wearable biopotential recording devices, the flexible dry electrode with micropillar array is designed and fabricated by MEMS process. The testing result shows that the skin-electrode contact impedance of the flexible mciropillar electrode is lower an order magnitude than that of the flexible flat electrode without micropillar array structures. Moreover, the contact impedance of this fabricated electrode was stable during two-day continuous testing, which indicates the flexible dry electrode is suitable for long-term measurement. In order to investigate the effect of motion artifact on the ECG signal, ECG signals are recording under two statuses of resting and walking. The ECG signals measured by the fabricated micropillar electrode were good fidelity, and did not degrade because of the motion. (C) 2015 Published by Elsevier B.V.