Instrumentation for measuring light, X-ray and neutron scatering during deformation and flow
| When |
May 09, 2023
from 11:00 to 12:00 |
|---|---|
| Where | Salle des thèses |
| Attendees |
Christopher Garvey |
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The ability to probe structure during deformation and flow with both spatial and temporal resolution enables insight into the molecular mechanisms which are associated with the response of the material. Scattering techniques provide important statistical and non-destructive perspectives on structure and dynamics over the volume of a sample illuminated by the probing radiation. Measurements can be made in a range of different flows/shear situations determined by the ability to define the interaction with the probe radiations. In simple flows, structure may evolve in response to the flow, or adopt a steady-state configuration. Each case, where structure changes over time, or where a steady state configuration is adopted, requires slightly different considerations in terms of scattering data acquisition. In the case of transitory states, modern detector electronics allow data acquisition to be synchronized with the deformation, and structural information may be enhanced by the multiple sampling of the same steady perturbed state. Different experimental approaches are described with an emphasis on data quality and analysis. Specific examples are given with an emphasis on small-angle scattering:
1. Molecular configurations in response to polymer melts to extensional flow (Fig. 1). [1]
2. Distribution and orientation of red blood cells in Couete [2] and drug delivery platelets in channel flow.[3]
3. Colloidal gelation in Couete flow.[4]
[1] K. Mortensen, A.L. Borger, J.J.K. Kirkensgaard, C.J. Garvey, K. Almdal, A. Dorokhin, Q. Huang, O. Hassager, Structural Studies of Three-Arm Star Block Copolymers Exposed to Extreme Stretch Suggests a Persistent Polymer Tube, Physical Review Letters, 120 (2018).
[2] C. Garvey, R. Knot, E. Drabarek, P. Kuchel, Shear-induced alignment of self-associated hemoglobin in human erythrocytes: small angle neutron scattering studies, European Biophysics Journal With Biophysics Letters, 33 (2004) 589-595.
[3] J.T. Lovegrove, R. Raveendran, P. Spicer, S. Förster, C.J. Garvey, M.H. Stenzel, Margination of 2D Platelet Microparticles in Blood, ACS Macro Letters, (2023) 344-349.
[4] L. de Campo, C.J. Garvey, C.D. Muzny, C. Rehm, H.J.M. Hanley, Micron-scale restructuring of gelling silica subjected to shear, Journal of Colloid and Interface Science, 533 (2019) 136-143