Cocrystal effect-driven ultrafast phase-transition ionogel for dynamically switchable adhesion interfaces

Abstract

Smart adhesion materials are paramount to the construction of dynamic adhesion interfaces in domains such as flexible electronics, soft robotics, and precision manufacturing. Research focuses on resolving the inherent contradiction between material adhesion and switchability. Herein, we report a poly(ionic liquid)/ionic liquid cocrystal ionogel that combines the advantages of polymer and small-molecule phase transitions, enabling rapid and repeated switching between strong-weak adhesion states while simultaneously converting adhesion changes into electrical signal feedback to the external environment. The study shows that the long alkyl chains in the two components form a cocrystal structure, with the crystallization-melting temperature precisely controlled by the alkyl chain length (−10 to 60 °C). The ultrafast phase transition (t1/2 < 1 ms) of the ionogels leads to significant changes in the viscoelastic/electrical behavior, thereby inducing switching in adhesion (peel strength >1000 N/m, switching ratio >120) and electrical properties (switching ratio: 10²−10³). Based on the adhesion-electrical coupling effect, we design a dual-mode smart capture patch with dynamically feedback-regulated adhesion to enable objects’ free pickup and release. This work provides a pathway for designing smart adhesive materials for dynamic adhesion interfaces.