Semidilute solution self-diffusion coefficient

The self-diffusion measurements on semidilute solutions do show that for molecular weight of the labeled chains identical to that of the unlabeled chains one recovers the reptative behaviour observed in the case of a frozen matrix above entangled regime exists for 1 < <)>/< > < 10, however, the self-diffusion coefficient in this regime is not of the Rouse type. 

Mutual and Self-Diffusion Coefficients in Semidilute Solutions 24... 

Furthermore, the concentration dependence of the apparent diffusion coefficient has been investigated. The determination of the hydrodynamic radius from the diffusion coefficient is valid only when pure self-diffusion is measured, that is, when the experiment is performed in the dilute concentration range. In the semidilute or concentrated regime, interactions between individual solute molecules have to be considered. Whether interactions... 

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