How mobile individual polymers are reveals a lot about their macroscopic properties. Neutron researchers at Forschungszentrum Jülich have now found a much easier and more accurate way of investigating the often decisive lateral deflection of molecules. They use ring-shaped molecules as probes, which wrap themselves around the polymer chains and follow their lateral motion. Longitudinal motion, which can falsify the results, is not displayed. The method improves predictions, for example, of the flowability of polymer melts in plastic production. The findings have been published as the Editor’s Suggestion in Physical Review Letters and a viewpoint on it has also been posted on the American Physical Society’s Physics portal. (DOI: 10.1103/PhysRevLett.115.148302).