This research feature had rather a troubled gestation period. We started by preparing 3D models of the polyelectrolyte chains – shown right. These were animated to bring them together so that we could show salt formation between the poly(amine) and the poly(acid) at the interface. Unfortunately it was not at all clear what was going on, so we went back to the drawing board…
The final feature uses a single still graphic to show how the different polymers can attract each other at neutral pH, whilst having no affinity in either acid or base. We then illustrated this by re-producing one of the experiments described in the paper – which results in the two surfaces popping apart when they are immersed in acid.
Switchable adhesion is potentially very useful. Most things are made out of more than one material, and this makes recycling very difficult. Traditional glues are OK, but they usually require heat or organic solvents to break them up. This simple demonstration of a glue that stops being sticky in acidified water shows that this can be done easily, and in an environmentally friendly manner.
For the complete story see: Nanofolio research – switchable adhesion.