Deformable conductors for human-machine interface

Soft electronic systems are emerging that are heralded to bring revolution and a frontier for the interactions between human beings and machines. Interactive interfaces enable integrated bidirectional functionalities of sensing the external stimulus and providing interactive response to the users. Human body is considerably soft and stretchable; this characteristic puts forward the need for good mechanical conformabilities for the interfacing electronic devices. As a vital and indispensable component in electronic systems, soft and deformable conductor is of great importance to establish the enabling technologies. Significant progresses have been developed with new strategies and materials being exploited to improve the performance of elastic conductors. In this article, we review the latest advances in deformable conductors and their applications to enable soft electronic devices for human machine interfaces. We first focus on the important characteristics of the deformable conductors in their stretchability, conductivity, and transparency. Representative soft electronic systems that are categorized into receptive devices and responsive devices are then reviewed.