Interfacial adhesion effects of liquid metal printed electronics on general substrates: Mechanisms and applications

Printed electronics technology, characterized by its low cost, large-area compatibility, operational simplicity, and high-speed processing, has been extensively utilized in the fabrication of flexible electronic devices. Liquid metals, with their exceptional electrical conductivity and room-temperature fluidity, are considered ideal materials for the development of flexible and stretchable electronics. However, the adhesion mechanisms at the interface between liquid metals and substrates, a fundamental aspect of liquid metal-based printed electronics, have not been comprehensively explored in the existing literature. This review first introduces the fundamental properties of liquid metals and their adhesion mechanisms to various substrates, followed by a summary of printing technologies designed to enhance or reduce substrate adhesion. Additionally, techniques for printing on non-adhesive substrates through material modification, as well as methods for achieving detachment on adhesive substrates by controlling interfacial properties, are demonstrated. Finally, future research challenges and developmental trends in materials, methods, equipment, and applications are discussed. This review provides a comprehensive understanding of the interfacial adhesion effects between liquid metals and substrates, offering valuable insights for printing on a wide range of substrates, including plastics, silicones, paper, and even biological surfaces. (Figure presented.).