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 ^CyclicFP-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, ^CyclicFP-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, ^CyclicFP-fmoc achieves an unprecedented level of ductility despite being a small molecule. Detailed investigations using solid-state NMR and FT-IR revealed that ^CyclicFP-fmoc forms F-F interactions with the surface of PTFE.