A chemical process that could produce lighter, stronger plastics has been developed by Edinburgh University scientists working in conjunction with researchers at Finland’s Jyväskylä University. The team has managed to tie molecules at the nanoscale into complex knots that could give materials increased versatility. Success has been achieved in tying a molecule into a pentafoil knot — the most complex knot yet made with a molecule. The team is optimistic that the pentafoil knots will mimic the characteristics of the complex knots found in proteins and DNA, which help make certain substances elastic. Being able to produce materials with a set number of well-defined knots could provide scientists with greater control when they are designing new materials. The researchers used a technique known as self-assembly, which produced a chemical reaction in which atoms were chemically programmed to spontaneously wrap themselves into the desired knot.
The Edinburgh team is the first to produce a knot with five crossing points. Until now, only scientists have created the simplest type of knot, the trefoil, with three crossing points. The process is easy to replicate by following the recipe discovered using the special chemical building blocks developed. Knots and entanglements in molecules are responsible for the elastic properties of rubber and plastics. So by being able to design molecules with particular knotted structures we may be able to make materials and plastics with improved elastic or shock-absorbing properties.