This title appears in the Scientific Report :
2008
Please use the identifier:
http://dx.doi.org/10.1088/0953-8984/20/40/404207 in citations.
Please use the identifier: http://hdl.handle.net/2128/4685 in citations.
Dynamic response of block copolymer wormlike micelles to shear flow
Dynamic response of block copolymer wormlike micelles to shear flow
The linear and nonlinear dynamic response to an oscillatory shear flow of giant wormlike micelles consisting of Pb-Peo block copolymers is studied by means of Fourier transform rheology. Experiments are performed in the vicinity of the isotropic-nematic phase transition concentration, where the loca...
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Personal Name(s): | Lonetti, B. |
---|---|
Kohlbrecher, J. / Willner, L. / Dhont, J. K. G. / Lettinga, M. P. | |
Contributing Institute: |
JCNS; JCNS Streumethoden; IFF-4 Weiche Materie; IFF-7 Neutronenstreuung; IFF-5 |
Published in: | Journal of physics / Condensed matter, 20 (2008) S. 404207 |
Imprint: |
Bristol
IOP Publ.
2008
|
Physical Description: |
404207 |
DOI: |
10.1088/0953-8984/20/40/404207 |
Document Type: |
Journal Article |
Research Program: |
Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) Kondensierte Materie |
Series Title: |
Journal of Physics: Condensed Matter
20 |
Subject (ZB): | |
Link: |
Get full text OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://hdl.handle.net/2128/4685 in citations.
The linear and nonlinear dynamic response to an oscillatory shear flow of giant wormlike micelles consisting of Pb-Peo block copolymers is studied by means of Fourier transform rheology. Experiments are performed in the vicinity of the isotropic-nematic phase transition concentration, where the location of isotropic-nematic phase transition lines is determined independently. Strong shear-thinning behaviour is observed due to critical slowing down of orientational diffusion as a result of the vicinity of the isotropic-nematic spinodal. This severe shear-thinning behaviour is shown to result in gradient shear banding. Time-resolved small-angle neutron scattering experiments are used to obtain an insight into the microscopic phenomena that underlie the observed rheological response. An equation of motion for the order parameter tensor and an expression of the stress tensor in terms of the order parameter tensor are used to interpret the experimental data, both in the linear and nonlinear regimes. Scaling of the dynamic behaviour of the orientational order parameter and the stress is found when critical slowing down due to the vicinity of the isotropic-nematic spinodal is accounted for. |