Recent advances in telemedicine and personalized healthcare have motivated a wave of new developments in wearable technologies targeting continuous monitoring of biosignals. The common limitations of wearables for continuous monitoring are the durability, flexibility and breathability of their biopotential electrodes interfacing the body. Our studies tackle these challenges by proposing flexible, breathable, and washable dry textile electrodes made of electroactive fibers. In this thesis, we developed conductive elastomeric filament (CEF) fibers through melt spinning. Using an industrial scale knitting machine, CEF fibers were directly knitted into dry textile electrodes. Underwear and headband garments with integrated textile electrodes were knitted and electrocardiograms (ECGs) were acquired using the underwear garment and electrooculograms (EOGs) were acquired using the headband. ECG and EOG recordings with textile electrodes were found to have comparable fidelity to that of the gold standard gel electrodes. CEF electrodes were continued to acquire high-fidelity ECGs and EOGs after 30 wash and dry cycles. Smart underwear garments were also used to perform continuous ECG measurements in 5 participants over 24-hour of unrestricted daily activities. Results demonstrated the success of these garments in performing high fidelity continuous ECG monitoring.

We also developed novel multifunctional electroactive fibers with various cross-sectional geometries for electrophysiological applications. Different fiber materials with cross-sectional geometry of round, ribbon, and trilobal were coated using poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:​ PSS) biocompatible conductive ink through a continuous roll-to-roll coating technique. Physico-chemical interactions between the fiber substrates and PEDOT:​PSS ink were calculated based on the Owens, Wendt, Rabel and Kaelble (OWRK) method. Coated fibers were knitted into 3D textile electrodes using an industrial knitting machine. The electrochemical impedance spectroscopy, skin-electrode impedance, and ECG signals of the knitted electrodes after repetitive wash cycles were used as criteria to study the electrode’s performance for biomedical applications. The results showed that factors such as capillary force, cross-section of the filaments, and type of polymer materials affect the adhesion properties of the conductive ink to the fiber substrates.

Collectively, the results of our studies present novel dry textile electrodes as a promising scalable solution to the challenges of wearable technologies for long-term continuous electrophysiological monitoring applications.