Underwater "Smart Glue" Can Be Detached in Just Seven Seconds with the Press of a Button

Engineers at Michigan Technological University (MTU) have developed a "smart glue" prototype which can stick surfaces under water — then unstick them again on-demand, taking just seven seconds to switch between states.

Making a glue which works under water isn't too difficult, but making a "smart" glue gets tricker: The ability to glue two surfaces together then separate them on demand is extremely useful, but tricky — and previous efforts have concentrated on adjusting the acidity of the adhesive. This new approach, by contrast, uses electricity — making, effectively, a switch that can disable the glue's adhesion.

"A lot of people have been using catechol to mimic mussels and their adhesive proteins, but applying electricity to deactivate it is new,” explains Professor Bruce Lee. “It’s more convenient than using pH like what we were using before and it should be easier to integrate with electronic devices, which means detaching could be automated and could be as simple as pushing a button."

To test the approach, researcher Saleh Akram Bhuiyan used a titanium sphere with platinum electrodes. The smart glue was applied to the sphere; when a high enough voltage ran through the electrodes, the glue detached in just seven seconds.

"The novelty is application of the electricity and the short amount of time it takes to detach," says Bhuiyan. "What I find most unusual about the experiment is the color change. It starts white and when I apply the electricity and the material is deactivated, it oxidizes and turns a red color — and we really like to see that red color."

Currently, however, the process is one way; the team are now working on reversing the process, allowing the glue to become truly "smart" and be attached and detached at will with nothing more than the application of electricity.

The team's work has been published under closed-access terms in the Journal of the American Chemical Society.