Fabrication of an E-Textile Bioelectrode Array With Screen-Printed Wiring and an Ionic Liquid Gel Toward Cutaneous Whole-Body Electromyography

Abstract

We propose an e-textile bioelectrode array that consists of screen-printed silver paste wiring, a thermoplastic polyurethane insulation layer, and ionic liquid gel-embedded knit textile pads for wearable whole-body medical and healthcare monitoring. The technical challenges in integrating bioelectrodes onto knit textile include forming an insulation layer on silver paste wiring and fixing an ionic liquid gel on the wiring since the screen-printed silver paste wiring is removed by the organic solvent in conventional insulation ink and the adhesive force between the wiring and ionic liquid gel is weak. Our proposed e-textile bioelectrode array structure includes a laser-patterned hot-melt urethane film thermally attached to silver paste wiring on a polyurethane film and fabric to avoid wiring disconnection. An ionic liquid gel is formed and fixed in the conductive polymer-coated knit textile pad, which is fixed to an electrode with a hot-melt urethane film to improve the adhesive force. A $6\times3$ bioelectrode array of 1 cm2 ionic liquid gel pads is fabricated for electromyography. The impedance between the electrode and skin is 1 $\text{k}\Omega $ at 1 kHz, which is the same as that of a medical electrode. The adhesive force of the ionic liquid gel to the wiring is improved to 10 N. Finally, the erector spinae muscles are measured with our e-textile bioelectrode array, and the distribution of the flexion relaxation phenomenon can be measured to investigate back pain, leading to a medical diagnosis for plastic surgery or other divisions and healthcare applications.

Keywords

• Bioelectrode
• conductive polymer
• electronic textile
• EMG
• health monitoring
• ionic liquid