Enhancing Multifunctionality and Performance Indicators of Resistive‐Type Strain Sensors with Advanced Conductive Hydrogels

Abstract

Hydrogels are excellent options for strain sensors as they can stretch, endure mechanical stress, and possess multifunctional qualities. Resistive sensors are particularly promising among the diverse hydrogel strain sensors available. This is attributed to their dedicated focus on improving the indicators of strain‐sensing performance, simplicity of equipment, straightforward sensing mechanisms, and easy design of conductive hydrogels. Various approaches have been explored to create conductive hydrogels, including conductive fillers, conductive polymers, and ionic approaches. This review thoroughly explores diverse approaches for developing advanced conductive hydrogels for resistive‐type hydrogel strain sensors. The focus is particularly on their electrical conductivity and sensing performance indicators, distinguishing them as valuable resources for researchers in the field of strain sensors. First, diverse approaches for achieving electrical conductivity in hydrogels are introduced. The subsequent discussion delves into the multifunctionality of these conductivity approaches for hydrogels. In addition, it also scrutinizes recent applications of strain sensors. Overall, it offers comprehensive updates on the performance indicators such as sensitivity, working range and linearity, response and recovery times, and hysteresis of strain sensors using diverse approaches to conductive hydrogels. This study also includes the latest trends and future perspectives of resistive‐type hydrogel strain sensors.