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Univ. Paris-Saclay
Nanoscale to Microscale Structural Analysis with Neutrons
Judith Houston
Mercredi 04/11/2020, 15:00-16:01

The interactions and assembly behaviour of a product’s components in the nano-range, such as the colloidal building blocks in milk, or the polymer chains in plastic thin film coverings, determine not only the structure of the material at the nanoscale, but also directly influence that materials’ structure, rheology and functional properties at the macroscopic scale. Therefore, when designing new products, such as food, drug formulations or packaging, it is increasingly important to understand the relationship between the structural and functional properties of that material’s constituent components.

Small-angle neutron scattering (SANS) is an ideal technique to help us unravel complex soft matter structures on the 1-500 nm scale. The specific properties of neutrons, such as their capability to distinguish light elements and their isotopes (e.g. 1H (hydrogen) and 2H (deuterium)), or their negligible absorption, make them particularly useful in the field of soft matter. Firstly, by selectively deuterating components of a complex material, we can create contrast in an otherwise homogenous system without altering its physico-chemical properties. Such components can then be rendered effectively invisible in the measured scattering data when combined with judicious selection of the solvent. Therefore, this method of contrast-variation enables full structural characterisation of not only the global structure, but also its constituent components and their interaction, which cannot be obtained by light or x-ray scattering. In addition, the comparatively weak interaction between neutrons and matter, enables them to penetrate most materials. As a result, we can design relatively complex sample environments for in situstudies with neutrons. This has powerful implications for studying the evolution of nanoscale structures in industrial processes, without the need for overly simplified model set-ups. Finally, their non-invasive nature makes neutron perfect to study bio-relevant material without radiation damage.

This talk will include numerous examples from the literature aiming to highlight the versatility of neutron scattering for industrial applications, from understanding the structure of food or packaging to demonstrating the flexibility of neutrons to study processing techniques.


Contact : Alain MENELLE



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