Dynamics of a Polymer Solution

Dynamics refers to the property that involves the time t. The scattering law 5(Q, ) and the intensity 7(Q, t) are related to the correlation function G(r, f) in the following equations (a Fourier transform pair)  

For a simple liquid, the intensity 7(Q, f) can be described in terms of a self-diffusion coefficient D (see Chapter 11) by 

The self-diffusion coefficient is used to describe the center-of-mass motion for a simple liquid. It can also be used in connection with the Rouse-Zimm model to describe the behavior of a long chain. The determination of diffusion coefficient D 

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H. Yanase, P. Moldenaers, V. Abetz, J. van Egmond, G. G. Fuller, and J. Mewis, Structure and dynamics of a polymer solution subject to flow-induced phase separation, Rheol. Acta, 30, 89 (1991). 

Chu et al. have studied the structure and dynamics of a polymer solution composed of PS(polystyrene), PMMA(poly(methyl methacrylate)), TOL(toluene), and CNA(a-chloronaphthalene). According to the photocount intensity-intensity time correlation function measurements of the PMMA probe in the PS/MS(mixed solvent) isorefractive matrix, one surprising feature was that at least two dominant characteristic modes appeared even at small scattering angles. While the slow mode could be identified with the translational motion of the center of mass of the PMMA probe chain, it remained unconfirmed that the fast mode might be related to a coupling of PMMA motion with the cooperative motion of the isorefractive PS/MS(matrix). 

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