Surface and Interface Chemistry in Flexible Electronics

Flexible electronics is an emerging research hotspot, which involves chemistry, physics, materials, etc.. As an interdisciplinary topic, flexible electronics have been used in various fields, such as wearable devices, bio-medical applications, artificial intelligence. The fabrication of flexible devices requires the integration of different materials including flexible substrates, conductive materials, and functional components. Their integration is limited by their surface properties and interfacial interactions, their function and reliability are also influenced by the stability of their interfacial bindings. Thus surface and interface treatments, including chemical treatments, are important for fabrication and functionalization of flexible electronic devices. In this review, the application of surface/interface chemistry in flexible electronics will be cataloged into 3 types. Firstly, electrochemical reactions on surface, which are the bases for flexible chemical sensors and can be used to control the loading/release of chemicals on device surfaces. Secondly, surface modification, which can improve the processability of materials by varying their surface properties, and endow the devices with specific properties, functions, or protections. Lastly, interfacial connections, which link different materials and layers through covalent bonding or chemical process assisted physical entanglement, to improve the stability of the whole device. Summary and examples for each type will be given, followed by discussion of existing problems, possible future developments, and application potentials.