Hydrophobic ionogel with Mitigated sea-island structure: Exhibiting ultrahigh adhesion via cellulose-mediated energy...

Hydrophobic ionogels function as functional underwater materials, since their energy dissipation capability is crucial for ensuring structural stability. However, hydrogen bond-based energy dissipation mechanism is susceptible to water molecule interference, and conventional cellulose blend results in limited dissipative capacity. This study introduces a cellulose composite strategy to develop hydrophobic ionogel with a mitigated sea-island structure. Specifically, a novel composite interface was formed by incorporating alkylated cellulose with a high substitution degree (DS = 2.88) into the polymer matrix. The resulting structure enlarged the effective interfacial area, thereby strengthening interfacial friction and enhancing energy dissipation. Consequently, the hydrophobic ionogel exhibited ultrahigh adhesion, showing an interfacial toughness of 1.06 kJ/m² upon debonding from stainless steel. Remarkably, it retained a high interfacial toughness of 0.68 kJ/m² even for underwater adhesion. Furthermore, the ionogel demonstrated strong adhesion to substrates with different polarities, excellent reusability, remarkable acid/alkali resistance, and rapid wettability. Based on its excellent conductivity, it was used for underwater motion sensing, vital sign monitoring, and intelligent adhesion. These advances provide new insights for incorporating cellulose-mediated energy dissipation mechanisms in ionogels.