Small-Molecule Adhesives with Strong and Ductile Adhesion to PTFE, Yet Allowing Easy Wipe-Off Removal

Tough adhesion, combining high levels of both adhesive strength and ductility, is important for a wide range of everyday applications, but achieving it remains challenging because of the strength–ductility trade-off. Currently, only a few polymer adhesives provide tough adhesion by addressing this trade-off. In contrast, small-molecule adhesives offer advantages such as easy removability and recyclability; however, none have been reported to achieve tough adhesion because they cannot form entangled networks necessary for the emergence of ductility. Here, we report fluoro-crown ether phosphates such as Cyclic FP-fmoc as the first small-molecule adhesives that enable highly strong and ductile adhesion to a broad range of materials. Yet, they are readily removable by washing with ethanol. Notably, Cyclic FP-fmoc exhibits tough adhesion to polytetrafluoroethylene (PTFE), whose surface is highly inert and difficult to bond. By integrating multiple dynamic interactions, including F–F, hydrogen bonding, and π–π stacking interactions, Cyclic FP-fmoc achieves an unprecedented level of ductility despite being a small molecule. Detailed investigations using solid-state NMR and FT-IR revealed that Cyclic FP-fmoc forms F–F interactions with the surface of PTFE.