“This is a ‘one-pot’ glue and is water-based, so it does not emit organic solvent vapors and does not require a hardener, unlike some glues,” says Bassam Aljohani, a Ph.D. student in the school of engineering who is working on the R&D project. “It is also as strong as other water-based glues.

“The glue is made in the same way as a paint, but silver particles are added rather than pigments, and this gives the formulation its electrical properties,” explains Aljohani. “Other conducting glues exist, and many of these also include silver for optimal conductivity, but none can easily be debonded.”

According to Aljohani, reversible adhesive will help address challenges associated with electronic waste. “Electrically conductive adhesives have been around for a long time, and making them reversible provides the solution to a very real problem that urgently needs addressing,” he points out. “Being reversible, our glue [makes it possible to recover and reuse] silver, which is important to keep costs down and the environment clean.”

The adhesive is based on current industrial manufacturing processes used for making paint. And, because it’s developed from cheap materials, it can be scaled up easily.

“It is water-based, so it does not have the volatile organic solvents used in many commercial glues,” claims Aljohani. “But, unlike other water-based adhesives, exposure to humid environments does not cause bond failure. The glue works very well on metal surfaces; it also sticks to other surfaces, such as plastics and printed circuit boards.”

“The electronics industry relies on permanent joining methods, including screws, which can make automated recycling more difficult,” adds Ama Asiedu-Asante, Ph.D., an electrical engineer who worked on the project. “There is now increasing recognition that water-based formulations can support more sustainable electronics, and this [breakthrough] demonstrates how they can deliver both performance and reversibility.”