Seafood with a difference
There’s nothing more delicious than a steaming plate of mussels, particularly if it is accompanied by a bowl of fries. And living in Argyll there are plenty of mussels. But there is more to these humble bivalves than meets the eye.
Mussels live in colonies on rocks in intertidal zones, and anyone who has ever tried to collect them will know that they are stuck fast and are quite difficult to prize off. This is because mussels firmly anchor themselves to the rough, wet rock surfaces.
The threads that secure them are called byssal threads, which prevent them from being swept away by buffeting tides and waves. These threads form the beard of the mussel that needs to be removed before cooking.
The outer layer of a byssal thread contains iron and a substance called catechol, which bond together to give the threads a unique set of properties – they are tough, they can stretch without breaking and can reconfigure the molecular bonds when broken.
Inspired by the properties of byssal threads, scientists have now come up with a new plastic material that combines strength, elasticity and toughness. Its key component is the iron-catechol bond, called a ‘sacrificial bond’ because it breaks when forcefully hit or stretched, and in doing so it dissipates energy and allows the whole structure to stay intact. Once the stress is passed the bonds can reform making the material reusable.
The addition of iron-catechol bonds makes the resulting plastic stiffer, stronger and tougher than iron-free plastics, being over 700 times as stretchy and almost 60 times as strong. Scientists predict many uses for this new material including lifting, packing and anchoring heavy objects, and, more experimentally, its incorpo- ration into robot joints and perhaps in the longer term being used to repair damaged human joints and tendons.