Strong but Reversible Super Fatty Acid Adhesives with Adjustable On-Off Temperature

Reversible adhesion is highly desired for intelligent engineering, reassembling devices, and recycling resources. However, many reported reversible adhesives require solvent or pH stimuli to achieve adversity switches, which are very inconvenient for practical applications. So far, thermally responsive adhesives are reported to be very appealing in achieving facile reversible adhesion. However, the fixed on-off switching temperature limits their application in different scenarios. Herein, we report employing fatty acids and polyvinylpyrrolidone to construct supramolecular thermosetting adhesives. The adhesives can switch between solid and liquid states owing to phase transition, resulting in reversible adhesion with a robust strength of ∼4 MPa and a large on-off ratio of ∼40. Upon variation of the chain length of fatty acids, the super fatty acid adhesives can be designed to display reversible adhesion at the desired temperature. This study will open up new inspiration for developing high-performance reversible adhesives for sustainable development.