Unique relaxation mechanism behind case of negative thermal expansion

 A layer of three molecular chains organised into repeating near-ball shapes

Source: © Weiqun Shi/Chinese Academy of Sciences

New mechanism is ‘totally different’ from well-known hinging model

 Researchers in China have revealed a new relaxation-related mechanism in a material with negative thermal expansion (NTE). The group introduced organic linkers into the skeleton of a metal–organic rotaxane network to construct a flexible NTE material, which they envision will aid the design of other types of metal–organic materials with controllable thermal responsive behaviour.