Self-assembled molecular knot paves way for next-gen materials
Image credit: University of Manchester
Manchester University scientists have created what they call the tightest knot ever made, paving the way for next-generation extremely strong materials.
The knot is essentially a single molecular strand containing 192 atoms arranged in a closed loop with eight crossings and a total length of 20 nanometres.
The researchers believe that the achievement, described in the latest issue of the journal Science, will enable further enhancing the properties of the current generation of supermaterials.
“For example, bullet-proof vests and body armour are made of kevlar, a plastic that consists of rigid molecular rods aligned in a parallel structure – however, interweaving polymer strands have the potential to create much tougher, lighter and more flexible materials in the same way that weaving threads does in our everyday world,” explained Professor David Leigh from the University of Manchester’s School of Chemistry, who led the team.
“Some polymers, such as spider silk, can be twice as strong as steel so braiding polymer strands may lead to new generations of light, super-strong and flexible materials for fabrication and construction.”
The knot, the single most complex woven molecule artificially made, was created using a self-assembling technique in which molecular strands are woven around metal ions, forming crossing points in the right places similarly to knitting. The ends of the strands were then fused together by a chemical catalyst to close the loop and form the complete knot.
The knot is formed around a single chloride atom and contains iron ions and atoms of oxygen, nitrogen and carbon.
The ability to create different types of molecular knots will allow the scientists to probe how knotting affects strength and elasticity of materials which will enable them to weave polymer strands to generate new types of materials.