Electrochemical modification of silver coated multifilament for wearable ECG monitoring electrodes

This paper presents a method to fabricate textile structural electrodes from material preparation to electrode structure design and testing. Silver/Silver Chloride (Ag/AgCl) was assumed to be the best electrode material system for acquisition of biopotential signals. A/AgCl coating has been grown on silver (Ag) coated multifilament yarn to form Ag/AgCl combination using constant voltage electrolytic deposition in 0.9% w.t. sodium chloride bath. The AgCl thickness could be controlled by varying processing time (t) and voltage (V). Surface morphology of the treated fibres were studied by scanning electron microscopy (SEM) which revealed that AgCl grain size became bigger and denser as increased processing time and voltage. The impedance of the treated fibres were analyzed by electrochemical impedance spectroscopy (EIS) analysis from 0.1Hz to 1000Hz which shown that impedance also increased with processing time and voltage. The prepared Ag/AgCl multifilament yarn was fabricated into wearable electrode using embroidery technique. ECG testing confirmed that the electrodes made from treated fibre can acquire high quality signal.