ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.448969
