Smart Hydrogel Tactile Sensors and Systems: A Comprehensive Review

ABSTRACT The rise of wearable electronics and intelligent robotics has created an urgent demand for tactile sensors that are soft, biocompatible, and responsive. Hydrogels, with high water content and mechanical compliance such as biological tissues, provide a unique platform for constructing next‐generation tactile sensors that mimic human skin’s sensory functions. This paper surveys recent progress in smart hydrogel tactile sensors and systems from fundamental concepts to practical applications. Beyond molecular structural design and material selection, we focus on the discussion and summary of the key sensing mechanisms, including triboelectric, piezoresistive, piezoelectric, piezoionic, and piezocapacitive modes. We also discuss material innovations such as ionic hydrogels, dual‐conductive networks, zwitterionic matrices, and nanocomposite reinforcement, highlighting strategies to improve sensitivity, durability, and multifunctionality. Finally, the challenges and possible future directions for smart hydrogel tactile systems are outlined.