Starch-Based Conductive Hydrogels for Wearable Sensors: Preparation Methods, Conductive Structures, and Key Performance Enhancement Strategies

Starch is the most abundant natural polymer and plays a crucial role in the development of hydrogel materials. Starch-based conductive hydrogels have been widely applied in wearable sensors owing to their excellent electrical conductivity and biocompatibility. This review summarizes the recent advances in starch-based conductive hydrogels for wearable sensor applications. It outlines the relationships between the fundamental structure of starch and the resulting material structures and properties and clarifies the preparation strategies for starch-based conductive hydrogels. Then, the conductive structures of hydrogels are classified into three main categories: ionic conduction, electronic conduction, and ion-electron synergistic conduction. Within these categories, several subtypes of conductive network architectures are discussed in detail, including single-network, semi-interpenetrating network, interpenetrating network, and multiple-network structures. The review also covers key performance enhancement strategies required for starch-based hydrogels used in wearable sensors, including antiswelling capability, mechanical performance, self-healing ability, adhesion, environmental responsiveness, biocompatibility, and environmental durability. Overall, the current challenges in this field are analyzed, and potential future research directions are proposed to advance the development of starch-based conductive hydrogels for wearable sensor applications.