GEN-ERIC News

The glue is made up of polyelectrolytes, which are polymers that are electrically charged and can change their shape in response to their environment. A polyelectrolyte can either stretch out, when at one pH level, or roll into a ball at another pH. The researchers, led by Dr Mark Geoghegan in the Department of Physics and Astronomy at the University of Sheffield, showed that if oppositely charged polyelectrolytes are brought together in water they stick tightly. This was widely known, but until now the strength of this bond and the fact that the process can be reversed and repeated was a mystery. The study showed that the adhesion was nearly as strong as epoxy glue. Not only that, but when the water was made acidic, the two materials came apart. The separation of the two could also be reversed by immersing them again in water. The work is expected to have applications in nanotechnology where changes in pH levels can be used to control the not as yet invented nanoscale machines of the future. It is also thought it could aid in drug delivery.