双性イオンマイクロゲル強化ヒドロゲル：電気化学用途向け低ヒステリシス・高靭性

Hydrogels are widely used in flexible sensors and energy devices due to their excellent flexibility, conductivity, and biocompatibility. However, achieving a hydrogel design that simultaneously offers high toughness, low hysteresis, and outstanding electrochemical performance remains a significant challenge. Herein, zwitterionic microgels with a special chemical design were synthesized from monomer 3-(1-(4-vinylbenzyl)-1H-benzo[d]imidazol-3-ium-3-yl)propane-1-sulfonate (VBIPS), which were further incorporated into a highly entangled polyacrylamide (PAM) network to fabricate a tough, low-hysteresis hydrogel. The penetrated pVBIPS microgels acted as cross-linking domains, promoting toughness through efficient stress transmission and crack resistance with restricted energy dissipation. The obtained PAM/pVBIPS hydrogel showed high toughness (1450.8 kJ/m³) with no significant degradation in mechanics after loading 100 cycles at 100% strain. Besides, due to the zwitterionic nature of pVBIPS domains, the PAM/pVBIPS-ZnSO₄ hydrogel showed good conductivity (52.9 mS cm^-1) and exhibited excellent sensitivity (GF = 4.48) when applied as a strain sensor. Additionally, it demonstrates good electrochemical stability when applied in a zinc-ion hybrid capacitor, retaining ∼92.23% capacitance after 24 h in static conditions. These results collectively highlight the pivotal role of zwitterionic microgels in reinforcing the mechanical integrity and electrochemical functionality of the conventional PAM hydrogels.