Supramolecular adhesive materials based on urea assembly

Supramolecular adhesive materials (SAMs) have garnered significant research interest owing to the outstanding attributes offered by dynamic bonds, including self-healability, stimulus responsiveness, and reversible adhesion. Urea groups with adjustable hydrogen bond strength, directional assembly ability, readily synthesized and amenable to scale-up, represent crucial dynamic bond constituents; this review provides a comprehensive summary of SAMs based on urea assembly. Meanwhile, a comprehensive overview of SAMs' structures, prop-erties, and applications is also provided. SAMs are categorized into four distinct types following the quantity of urea-based assembly sites: one assembly site, two assembly sites, three assembly sites, and multi-assembly sites. Deduced out urea-based assembly promotes molecular weight and cross-linking points increase, which are the main factors for improving the performance of SAMs. The SAMs' limitations, challenges, and prospective di-rections are also briefly outlined.