Impedance analysis of ZnO nanowire coated dry EEG electrodes

Abstract

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 cm 2 for the bare electrode to 256 Ω cm 2 for the gold-coated electrode and further decreases to 167 Ω cm 2 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.

The Status of Textile-Based Dry EEG Electrodes

“…It is important to avoid uncomfortable cables, electrodes, lights, buttons, and sounds as this disturbs the patient and family, even more so in the long run. This was confirmed by a recent survey evaluating the desires of patients, which revealed a strong preference for a seizure detection device with little interference with daily activities [42]. Using textile electrodes, therefore, overcomes the related issues and would fill the gap of existing metal electrodes.…”

“…[11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47]…”

Dry Electroencephalography Textrode for Brain Activity Monitoring

“…Uncomfortable cables, electrodes, lights, buttons, and sounds should be avoided as this disturbs the patient and family, even more so in the long term. This was confirmed by a recent survey evaluating patients' desires that revealed a strong preference for a seizure detection device that had little interference with daily activities [2]. The use of textile electrodes could overcome the problems associated with metal-based dry electrodes like structural rigidity and weight and would fill the gap.…”

Physicochemical Studies on Nafion® Modified ZnO Interlayers for Enhanced Electron Transport in the Inverted Polymer Solar Cells

“…The obtained plot for each device exhibited a compressed semicircular plot with no proper distinction between the high and low‐frequency regions. Based on the graphical trend and previous reports, we fitted the data with a simple double Randle's circuit (Figure (d)). Here, R 1 denotes the total series resistance of the cell and (R 2 ‐Q) belongs to charge transfer and double layer capacitive elements in the ETL interface.…”

“…While it is easier to use for R&D purposes, PEDOT:PSS films have some well documented practical limitations because of its acidic nature that severely affects the life expectancy of OPVs . A non‐exhaustive observation revealed that the fabricated cells performed convincingly up to 2 weeks.…”