Bio-Inspired Adhesive with Reset-On Demand, Reuse-Many (RORM) Modes

摘要

Development of tough, reusable adhesives is important, but remains a majorchallenge, especially in water. A tough reusable adhesive that resets entirely toits virgin condition when needed is reported using caffeic acid. Here, caffeicacid is employed as adhesive moiety to achieve such the functions due to itsdual characteristics: an adhesive moiety from mussel-inspired catechol and aphoto-reversible crosslink from cinnamic acid. Adhesion involves a two-stepprocess. First, the caffeic acid-functionalized polymer is applied to theadherend, followed by UV irradiation (peak wavelength of light-emitting diode, _P: 365 nm) to form a durable pre-applied adhesive (PAA) layer throughcrosslinking among the caffeic acid moieties. Second, thermal activation ofthe PAA layer ensures repeated adhesion to a variety of adherends(Reuse-Many mode). The cyclic dimer of the caffeic acid moiety isde-crosslinked by UV irradiation at _P: 254 nm. This allows the completeremoval of the adhesive residues from the adherends when the adhesive is nolonger needed (Reset-On demand mode). Furthermore, using magneticnanoparticles, the caffeic acid-functionalized polymer can be activatedremotely under water by magnetic induction heating. This study paves theway for the rational design of bio-inspired adhesives that outperform natureusing plant-derived raw materials.