Printed textile-based electronic devices

Abstract

Printed textile-based electronic devices are reviewed. The primary printing techniques utilized are screen and inkjet printing. Conductive tracks can be achieved by means of directly printing on the textile or via an interface priming layer which is first printed to smooth the textile. Conductive tracks can be used to fabricate simple electronic tracks for use as interconnects in a printed circuit board and a fabric antenna or for biopotential monitoring. Combining a dielectric and a conductive layer allows the formation of capacitors on textiles. Force sensing can be achieved by means of printed resistors or piezoelectric materials. Printed resistors can also be used to produce a heater. Energy harvesting on fabric can be achieved by means of printed semiconductor layers based on thermoelectric harvesting and solar cells. Color variation on fabric can be achieved by printed chromic layers which change color in response to heat (thermochromic) or electrical stimulus (electrochromic). Light emission can be achieved by printed electroluminescent layers. Sacrificial layer technology allows the formation of three-dimensional structures on fabrics such as cantilevers which can be used for motion sensing. Devices must be sufficiently robust to be suitable for daily use in particular in respect of bending, abrasion, and washing. The durability to bending can be tested by flexing the printed conductive layer around a mandrel. Abrasion durability is evaluated by rubbing the printed conductive textile against a 100 % wool textile with a specific force loading. Wash durability is the most critical function for everyday wearable electronics. Encapsulation, either by lamination or printing, is an effective method to improve the washing durability.