Innovating flexible touch panels: Advanced conductive hydrogels for next-generation interfaces

Flexible touch panels are becoming increasingly vital in the evolution of human-machine interfaces, intelligent robotics, and wearable technology. Conductive hydrogels, with their unique combination of flexibility, transparency, and biocompatibility, are emerging as essential components for next-generation flexible touch panels. Various conductive hydrogel systems based on polymers such as polyvinyl alcohol, polyacrylamide, and polyacrylic acid have been developed, enabling diverse device structures like sandwich, array, and woven configurations. This review offers a comprehensive overview of hydrogel-based flexible touch panels, focusing on their distinctive properties, diverse working principles, and wide-ranging applications. It explores the integration of conductive hydrogels in various mechanisms, including capacitive, resistive, and triboelectric touch panels, emphasizing their role in enhancing device functionality. Additionally, the review addresses critical challenges, such as material stability, durability, and sensitivity, while providing insights into potential innovations and future research directions. By covering both current developments and emerging trends, this review aims to advance the understanding and evolution of this rapidly growing field.