R2R-Based Continuous Production of Patterned and Multilayered Elastic Substrates with Liquid Metal Wiring for Stretchable Electronics

The roll-to-roll (R2R) process for fabricating elastic substrates is essential for the social implementation of next-generation stretchable devices with soft interfaces. In recent years, there is a growing demand for soft heterostructures with multiple monolithically patterned organic materials. However, a continuous processing technique for substrates with heterostructures patterned using highly stretchable wiring has not yet been developed. Conventional manufacturing methods for stretchable electronics lack production capacity. This study introduces an R2R-based method for the continuous production of multilayered substrates composed of various elastic materials, integrated with liquid metal (LM) wiring, suitable for stretchable electronics. Continuous fabrication of polymer films is achieved with pattern areas as small as 0.78 mm², using three different polymers varying in hardness. The R2R coating process, paired with liquid metal wiring dispensing printing, allows for the creation of lines as fine as 140 microns. This process supports the batch production of 15 stretchable hybrid devices at a time and enables the creation of large-area devices up to 400 cm². The fabrication technique developed herein holds promise for the future manufacturing of not only stretchable electronics but also cutting-edge soft electronics like smart packaging. This is expected to be a factor leading to the commercialization of stretchable electronics.