Scientists discover a reversible super-glue inspired by snail mucus

Snails secrete a mucous membrane that acts like a superglue, allowing them to adhere to rough surfaces like rocks.

Inspired by this aspect of snail biology, scientists at the University of Pennsylvania, Lehigh University and the Korea Institute of Science and Technology have created a glue-like material that is "inherently reversible" . In other words, it can easily be taken off.

Adhesives are everywhere – in everyday life and in industrial applications. Achieving both strong adherence and reversibility (or the ability to reverse membership) is a challenge. According to Anand Jagota, professor and founding chairman of the bioengineering department of Lehigh University, this is especially true for hydrogels containing 90% water.

He says that adhesives generally belong to one of two classes: strong but irreversible, like superglues, or reversible and reusable but weak.

The team managed to overcome these limitations. They reported their findings in an article published today in Proceedings of the National Academy of Sciences called "superglues intrinsically reversible via a shape adaptation inspired by the snail epiphragm".

"We describe a reversible adhesive-based hydrogel adhesive by combining the advantages of liquid and dry adhesives into a single material," says Jagota.

The team reports that, once hydrated, the softened gel that they created fits in a manner consistent with the target's surface by low energy deformation, which is then blocked during the drying of the target. similar way to the action of the epiphragm of snails. An epiphragm is a temporary structure created by snails and molluscs. Made of dried mucus, it retains moisture during periods of inactivity and allows snails to adhere to surfaces, like rocks.

Scientists have shown that a super strong reversible adhesion can be obtained from an unstructured material when the shape matching criterion is fulfilled, with minimal residual strain energy stored in the system. According to the researchers, the new material can be applied to flat or rough target surfaces.

"We demonstrate that, in this system, the strength of adhesion is based on the intrinsic properties of the material, particularly near the surface, and not on a structure close to the surface, which allows for reversibility and setting. on the scale for practical applications, "says Shu Yang, professor of materials science. and engineering and chemical and biomolecular engineering at the University of Pennsylvania and lead author.