Enhancing the Performance of Stretchable Conductors for E-Textiles by Controlled Ink Permeation

Delivery of electronic functionality to the human body using e-textiles is important for realizing the future of wearable electronics. Printing is a promising process for large scale manufacturing of e-textile since it enables arbitrary patterns using a simple and inexpensive process. However, conductive inks printed atop of textile are vulnerable to cracking because of the deformable and porous structure of textiles. The authors develop a mechanically and electrically robust wiring by controlling ink permeation in the structure of textile. This is done by adjusting the ink's solvent. The use of butyl carbitol acetate, with its low vapor pressure and boiling point, enables deep permeation into the textile. The sheet resistance is initially 0.06 Ω sq^-1 , and the resistance increasing only 70 times after stretching to 450% strain. Finally, a four-channel electromyogram (EMG) monitoring garment is demonstrated to show the potential of a large-scale e-textile device for health care and sports.