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Proceedings Paper

Application of probe diffusion models to sphere diffusion in a rod/sphere composite liquid
Author(s): Mark A. Tracy; Robert Pecora
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Paper Abstract

Five composite liquid solutions (CL1-5) were prepared consisting of silica spheres and the rigid rod polymer poly(γ-benzyl α,L-glutamate) (PBLG) in the polar organic solvent dimethylformamide. The sizes of the macromolecular components in each solution were chosen such that the sphere radius/rod length ratio decreased from CL1 to CL5. The sphere diffusion constants in the composite liquids were measured as a function of the rod concentration by dynamic light scattering. Microviscosities (ημ ) as low as 1/2 of the solution viscosity (η) were found. The sphere diffusion constant data was fit to a stretched exponential of the form D/Do equals exp(-αcv) which is predicted by several models for the diffusion of spheres in polymer solutions. From these fits, we conclude (1) the stretched exponential fit is worst if ημ < η, (2) models predicting a stretched exponential offer no explanation for ημ < η, and (3) the experimentally determined values for v compare well to other experimental data but not to theoretical predictions.

Paper Details

Date Published: 21 July 1993
PDF: 12 pages
Proc. SPIE 1884, Static and Dynamic Light Scattering in Medicine and Biology, (21 July 1993); doi: 10.1117/12.148373
Show Author Affiliations
Mark A. Tracy, Enzytech, Inc. (United States)
Robert Pecora, Stanford Univ. (United States)


Published in SPIE Proceedings Vol. 1884:
Static and Dynamic Light Scattering in Medicine and Biology
Ralph J. Nossal; Robert Pecora; Alexander V. Priezzhev, Editor(s)

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