Molecular nodes for the materials of the future

29 January 2019 | Written by La redazione

A research group from the universities of Bologna and Manchester has succeeded in comparing the characteristics of nano-nodes made on molecular chains of different lengths. The recently published study paves the way for the rise of a new generation of lighter, stronger and more flexible materials

Climbers and sailors know this well: when it comes to knots, length, tension and hold are factors that make a significant difference. Chemists, who often deal with similar but much smaller plots at the molecular level, know this just as well. However, if it is easy to compare and evaluate different nodes in the macroscopic world, when the dimensions become nanometric, things become much more complicated.

A research group of the University of Bologna and the University of Manchester for the first time managed to compare the characteristics of nano-nodes made on molecular chains of different lengths. The study, published on PNAS, promises to be the basis for future technological applications from which new, lighter, more resistant and more flexible materials can be created.

The nanometric nodes. The nodes, or interweaving at the molecular level, are a phenomenon commonly observed in nature: inspired by these natural structures, scientists have been able to develop strategies to realize artificial nano-nodes, intertwining molecules obtained by chemical synthesis and joining their ends. “These molecular nodes present an architecture that shows different analogies with macroscopic knots”, explains Professor Matteo Calvaresi, who coordinated the research group of the University of Bologna. “But if in everyday life it is easy enough to realize how the different length of a knot can affect its hold and its macrosopic properties, when it comes to nano-knots making the same evaluations is not so immediate”. The study. If to date it was not possible to compare, at a molecular level, nodes of different sizes, lengths and holdings, the study presented by the researchers from Bologna and Manchester offers a solution: scientists have been able to knot three molecular chains in the same way of three different lengths: 20, 23 and 26 nanometers. Thus, three nodes were born with the same shape but linked to molecular threads of different sizes, which the researchers were able to compare, highlighting their different characteristics. “This work - confirms Matteo Calvaresi - is of fundamental importance for the design of knotted molecular materials: the discovery of the properties that regulate nano-nodes will allow in the future to weave molecules in such a way as to generate on demand a new generation of lighter, more resistant and more flexible materials.