Dynamics and structure in complex liquids under shear explored by neutron scattering.
It is well established that the structural order of macromolecules can be affected by the application of shear. For example, triblock copolymers in aqueous solutions are known to aggregate for high concentrations. For increasing temperature the polymer micelles crystallize and offer a model system for the investigation of percolation and crystallization. The crystalline phases rearrange under shear. We correlate the structural assemblages of polymer micelles to the microscopic dynamics of the polymer monomers as well as to the solvent molecules at rest and under shear. We find the monomer dynamics affected by the different arrangements of the polymer micelles in aqueous solutions. For pronounced structural ordering we report on the monomer diffusion to become anisotropic under shear, with the diffusive mode in the direction of the shear gradient being slowed down with respect to that in the direction of the flow.
Wolff
Max
M
Lehrstuhl fuer Kristallographie und Strukturphysik, Universitaet Erlangen-Nuernberg, 91054 Erlangen, Germany. v-wolff@ill.fr
Magerl
Andreas
A
Frick
Bernhard
B
Zabel
Hartmut
H