The Use of Scattering Data in the Study of the Molecular Organisation of Polymers in the Non-Crystalline State

• Main Authors: Thomas Gkourmpis, Geoffrey R. Mitchell
• Format: Article
• Language: English
• Published: MDPI AG 2020-12-01
• Series: Polymers
• Subjects: polymer melt; polymer glass; conformational analysis; chain segment packing; neutron scattering
• Online Access: https://www.mdpi.com/2073-4360/12/12/2917

Scattering data for polymers in the non-crystalline state, i.e., the glassy state or the molten state, may appear to contain little information. In this work, we review recent developments in the use of scattering data to evaluate in a quantitative manner the molecular organization of such polymer systems. The focus is on the local structure of chain segments, on the details of the chain conformation and on the imprint the inherent chemical connectivity has on this structure. We show the value of tightly coupling the scattering data to atomistic-level computer models. We show how quantitative information about the details of the chain conformation can be obtained directly using a model built from definitions of relatively few parameters. We show how scattering data may be supplemented with data from specific deuteration sites and used to obtain information hidden in the data. Finally, we show how we can exploit the reverse Monte Carlo approach to use the data to drive the convergence of the scattering calculated from a 3d atomistic-level model with the experimental data. We highlight the importance of the quality of the scattering data and the value in using broad Q scattering data obtained using neutrons. We illustrate these various methods with results drawn from a diverse range of polymers.