Printed Stretchable Interconnects for Smart Garments: Design, Fabrication, and Characterization

This paper explores stretchability and fatigue life of inexpensive printed stretchable interconnects for smart garments. Multilayer stretchable interconnects are created on a knit fabric by screen printing of Ag/AgCl conductive inks on thermoplastic polyurethane film (TPU). Heat lamination of this layer onto a knit fabric and its protective encapsulation with a second TPU layer yields a multilayer stretchable interconnect structure. Design and optimization of the printed meandering interconnects are performed experimentally. The effect of processing steps, area of substrate, and encapsulation layers on the electro-mechanical properties of the stretchable interconnects are investigated. Washing endurance of the printed lines is also explored. The meandering stretchable printed line demonstrates stretchability of over 100% strain and fatigue life of 1000 cycles at 20% strain. Washing endurance of 100 cycles is reported. This paper presents an inexpensive method of realization of electronics integration on textiles by maintaining textile comfort and wearability.