Open AccessImpedance analysis of ZnO nanowire coated dry EEG electrodes
Author(s) -
Jiamin Wu,
Wenyan Jia,
Changhao Xu,
Di Gao,
Mingui Sun
Publication year - 2017
Publication title -
journal of biomedical engineering and informatics
Language(s) - English
Resource type - Journals
eISSN - 2377-939X
pISSN - 2377-9381
DOI - 10.5430/jbei.v3n1p44
Subject(s) - electrode , materials science , dielectric spectroscopy , electrical impedance , constant phase element , electrolyte , equivalent circuit , nanowire , composite material , electrochemistry , reference electrode , analytical chemistry (journal) , optoelectronics , voltage , chemistry , electrical engineering , chromatography , engineering
The electrochemical impedance of a novel dry electroencephalogram (EEG) electrode after surface modification (i.e., sputtered with gold, coated with ZnO nanowires) is investigated in this study. To avoid the discomfort caused by repetitive testing on human, a skin-mimic sandwich structure, comprised of a highly porous polyester fabric membrane and two thin silicone films, is fabricated as a test bed. Electrochemical impedance spectroscopy (EIS) measurements are conducted to further understand the properties of the electrode-electrolyte interface when the electrode is installed on this test bed. An equivalent circuit model with a constant phase element (CPE) is used to fit the EIS data. Our results show that the modeled EIS data are in good agreement with the experimental data. It has also been found that the charge transfer resistance decreases from 349 Ω cm2 for the bare electrode to 256 Ω cm2 for the gold-coated electrode and further decreases to 167 Ω cm2 for the gold coated short ZnO nanowire electrode. The lower impedance value will definitely help improve the signal when such electrode is used to record electrophysiological data.