Materials scientists are on the hunt for an adhesive that binds strongly to diverse surfaces and can be easily removed and reused. Conventional polymers like epoxies achieve high strength through rigid, cross-linked networks, but they are brittle and prone to sudden, catastrophic failure under stress. Conversely, adhesives used in tapes offer ductility but lack the strength for heavy-duty bonding.
Small-molecule glues utilize noncovalent bonds for adhesion, allowing the glues to be removed easily and to leave pristine surfaces behind. But they too lack tough adhesion, which is achieved when a material has both high ductility and high adhesive strength.
Now researchers have developed a small-molecule glue that not only bonds strongly to nonstick surfaces but is easily removed with ethanol (J. Am. Chem. Soc. 2026, DOI: 10.1021/jacs.6c07886). “It combines adhesive strength and ductility together with easy washability, which is needed for recycling the adhesive as well as reusing the adhered objects,” Takuzo Aida, a polymer chemist at the University of Tokyo, says in an email.
The white crystalline adhesive, synthesized by Aida’s team, is a fluoro-crown ether phosphate called CyclicFP-fmoc. To test its adhesive strength, researchers first glued two untreated polytetrafluoroethylene (PTFE) plates by sandwiching molten CyclicFP-fmoc between them and letting it cool at room temperature for 10 min. The plates, glued to each other by a tiny contact patch of just 7 cm2, were able to hoist an 8 kg weight and registered a staggering 1.3 ± 0.1 MPa on lap-shear tensile tests, eclipsing the 0.1–0.7 MPa limits of commercial epoxies, acrylics, and silicones.
CyclicFP-fmoc binds to Teflon via strong, interfacial fluorine-fluorine (F–F) interactions, solid-state NMR spectroscopy confirmed. Meanwhile, the glue molecules hold on to each other inside the adhesive layer via hydrogen bonding between urethane units and π-π stacking of the fluorenyl rings.
Remarkably, a simple ethanol wash completely stripped CyclicFP-fmoc from the target PTFE plates, leaving no trace behind. The recovered adhesive proved repeatedly reusable, reliably maintaining its adhesive strength of ~1.2 ± 0.1 MPa across multiple cycles.
Two polytetrafluoroethylene plates joined with a new glue, called CyclicFP-fmoc, are able to lift 8 kg of weight. Credit:
Kohei Kikkawa
“Since ethanol is the main component of hand sanitizer, we believe it is possible to de-bond and recycle the adhesive by using hand sanitizer as a substitute in certain real-world situations,” Aida says. He explains that due to the noncovalent bonds, recycling the adhesive simply involves a breaking of those bonds, yielding the original monomer, which can be reused with no loss of adhesive strength. “In general, this can’t be achieved by using polymer adhesives,” he adds.
Mechanical engineer Alban Sauret and bioengineer Phillip Messersmith, who were not involved in the study, both stress that it is imperative to study this molecule’s environmental fate and impact before pressing it into service.
Sauret, at the University of Maryland, found the adhesive’s combination of strength, ductility, and ethanol removability “quite unusual.” “The removable and recyclable nature of the adhesive is promising, as we would reuse fluoropolymer parts instead of discarding them,” he says. He finds it likely to be a member of the family of per- and polyfluoroalkyl substances (PFAS) based on its fluorinated structure, “but whether it behaves like a problematic ‘forever chemical’ is a separate question.”
Messersmith, at the University of California, Berkeley, notes that existing polymer adhesives “complicate recycling efforts . . . by making it hard or impossible to separate materials in a recycling stream.” If this new adhesive is not an environmentally harmful compound, he says, “the approach could allow for easy separation and recycling of adhesively bonded materials in the future.”
