Recent progress in low hysteresis gels: Strategies, applications, and challenges

Low hysteresis hydrogels refer to the hydrogels are capable of quickly returning to their original state after being subjected to external stress or deformation without obvious delay, which are widely used in fields that require frequent exposure to external forces or repeated folding because of their stable mechanical properties, excellent resilience, insensitivity to cracking and high fatigue resistance. The primary challenge in achieving low hysteresis lies in minimizing energy dissipation during cyclic loading and ensuring rapid stress transfer to prevent stress concentration. This paper focuses on strategies to reduce energy dissipation and provides a comprehensive review of the latest design mechanisms, including chain entanglement, phase separation, molecular structure design, and slidable cross-linking points. Furthermore, the paper explores the applications of low hysteresis hydrogels in flexible sensors, triboelectric nanogenerators (TENGs), human-computer interaction (HCI), and new energy batteries. Detailed explanations of the mechanisms for achieving low hysteresis are provided, along with a comprehensive summary of the mechanical and sensing properties of these hydrogels. The paper also discusses future development prospects and highlights the current limitations of low hysteresis hydrogels.