Phenomenological scaling laws for "semidilute'' macromolecule solutions from light scattering by optical probe particles
Phillies, George D. J. ; Ullmann, Gregory S. ; Ullmann, Kathleen ; Lin, Thy-Hou
College Park, Md. : American Institute of Physics (AIP)
Published 1985
College Park, Md. : American Institute of Physics (AIP)
Published 1985
| ISSN: |
1089-7690
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| Source: |
AIP Digital Archive
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| Topics: |
Physics
Chemistry and Pharmacology
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| Notes: |
Polymer solution dynamics may be inferred from light scattering spectra of dissolved optical probe particles. We compare a variety of probes in solutions of several polymers. In the "overlapping'' concentration/molecular weight regime, the Stokes–Einstein equation fails by up to a factor of 2, while the probe diffusion coefficient D follows a scaling law D/D0=exp(−aMγcνRδ) (c, M, and R are the polymer concentration, molecular weight, and the probe radius, respectively). Experimentally, γ=0.8±0.1, ν=0.6–1.0, and δ=−0.1 to 0, contrary to the theoretical predictions γ=0 and δ=1. With very high molecular-weight polymers, we observe a further "entangled'' regime, characterized by huge (104) failures of the Stokes–Einstein equation and the appearance of "fast'' modes in the scattering spectrum.
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| Type of Medium: |
Electronic Resource
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| URL: |