Electrophoresis measurement, macroscopic

In this chapter the formalism of nonequilibrium thermodynamics, is reviewed. This formalism is then applied to the theory of isothermal diffusion and electrophoresis. It is shown that this theory is important in determining the relations between the transport coefficients measured by light scattering and those measured by classical macroscopic techniques. Since much of this material is covered in other chapters, this chapter is very brief. Our presentation closely follows that of Katchalsky and Curran (1965). Other books that can be consulted are those of DeGroot and Mazur (1962) and Prigogine (1955). 

At fixed polymer concentration, p/fio decreases with increasing matrix molecular weight. Rodbard and Chrambach found that p is not independent of M, consistent with many other results on probe electrophoresis and sedimentation. Nonlinear (in E) mobility behavior was observed, namely the probe mobility increased at larger applied fields. The nonlinearity was more pronounced at larger polymer concentrations. The dependence of p upon E could be said to be shear thinning, but if so the relevant shear rate (for example, involving a thin layer around each probe) must be quite large, because direct measurement at lower shear rates found no dependence of the macroscopic on /c. 

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