In-situ temperature-controllable shear flow device for neutron scattering measurement--an example of aligned bicellar mixtures.
We have designed and constructed a temperature-controllable shear flow cell for in-situ study on flow alignable systems. The device has been tested in the neutron diffraction and has the potential to be applied in the small angle neutron scattering configuration to characterize the nanostructures of the materials under flow. The required sample amount is as small as 1 ml. The shear rate on the sample is controlled by the flow rate produced by an external pump and can potentially vary from 0.11 to 3.8 × 10(5) s(-1). Both unidirectional and oscillational flows are achievable by the setting of the pump. The instrument is validated by using a lipid bicellar mixture, which yields non-alignable nanodisc-like bicelles at low T and shear-alignable membranes at high T. Using the shear cell, the bicellar membranes can be aligned at 31 °C under the flow with a shear rate of 11.11 s(-1). Multiple high-order Bragg peaks are observed and the full width at half maximum of the "rocking curve" around the Bragg's condition is found to be 3.5°-4.1°. It is noteworthy that a portion of the membranes remains aligned even after the flow stops. Detailed and comprehensive intensity correction for the rocking curve has been derived based on the finite rectangular sample geometry and the absorption of the neutrons as a function of sample angle [See supplementary material at http://dx.doi.org/10.1063/1.4908165 for the detailed derivation of the absorption correction]. The device offers a new capability to study the conformational or orientational anisotropy of the solvated macromolecules or aggregates induced by the hydrodynamic interaction in a flow field.
Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut 06269, USA.
Yan
Y
Xia
Polymer Program, Institute of Material Sciences, University of Connecticut, Storrs, Connecticut 06269, USA.
Ming
M
Li
Canadian Neutron Beam Centre, National Research Council Canada, Chalk River Laboratories, Chalk River, Ontario K0J 1J0, Canada.
Norbert
N
Kučerka
Canadian Neutron Beam Centre, National Research Council Canada, Chalk River Laboratories, Chalk River, Ontario K0J 1J0, Canada.
Shutao
S
Li
Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut 06269, USA.
Mu-Ping
MP
Nieh
D020404:Glycerophospholipids / Q000737:chemistry; D057446:Hydrodynamics; D055595:Mechanical Phenomena; D008823:Micelles; D033363:Neutron Diffraction / Q000295:instrumentation*; D013057:Spectrum Analysis; D013696:Temperature
D020404:Glycerophospholipids; D008823:Micelles