ISSN:
1435-1536
Keywords:
Shear gradient
;
Couette flow
;
Couette apparatus
;
small angle neutron scattering
;
polymer conformation
;
polymer dynamics
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The deformation of the overall conformation of polystyrene,M w =280000 g/ mole in dilute solution in a constant shear gradient has been investigated by small angle neutron scattering (SANS). The experiments were performed with a new Couette-type apparatus, consisting of two concentric quartz cylinders in which the outer one rotates and the solution is confined in the gap between both cylinders. The observation of the elastic coherent small angle scatterring intensity at a shear gradient ofG=400 s−1 has revealed a distinct anisotropy of the scattering pattern on the two dimensional detector, as estimated from equilibrium chain dynamics. After extrapolation to zero angle and zero concentration two different values for the overall size of the single macromolecule parallel and perpendicular to the flow-direction are deduced.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01458334
