Dilute solution flow birefringence

B. H. Zimm. Dynamics of polymer molecules in dilute solutions Viscoelasticity, flow birefringence and dielectric loss. J Chem Phys 24 269-219, 1956. 

Zimm, BH, Dynamics of Polymer Molecules in Dilute Solution Viscoelasticity, Flow Birefringence and Dielectric Loss, Journal of Chemical Physics 24, 269, 1956. 

In this respect, another insufficiency of Lodge s treatment is more serious, viz. the lack of specification of the relaxation times, which occur in his equations. In this connection, it is hoped that the present paper can contribute to a proper valuation of the ideas of Bueche (13), Ferry (14), and Peticolas (13). These authors adapted the dilute solution theory of Rouse (16) by introducing effective parameters, viz. an effective friction factor or an effective friction coefficient. The advantage of such a treatment is evident The set of relaxation times, explicitly given for the normal modes of motion of separate molecules in dilute solution, is also used for concentrated systems after the application of some modification. Experimental evidence for the validity of this procedure can, in principle, be obtained by comparing dynamic measurements, as obtained on dilute and concentrated systems. In the present report, flow birefringence measurements are used for the same purpose. 

When eqs. (2.24) or (2.24a) are applied to dilute solutions some additional assumptions should be stated explicitely. First of all, it is assumed that the contributions of the solvent to shear stress and flow birefringence are independent of the solute concentration and equal to the shear stress and flow birefringence of the pure solvent, as measured at the corresponding shear rate. This assumption becomes more and more incorrect when the solute concentration is increased. However, this is of minor importance as, in general, with increasing concentration the said contributions of the solvent become very small when compared with the effects of the whole solution. Second, it is assumed that the solvent effect can simply be subtracted from the whole effect. In this way, instead of eq. (1.5) one obtains ... 

Pokrovskii VN, Kokorin YuK (1987) The theory of oscillating birefringence of solutions of linear polymers. Dilute and concentrated systems. Polym Sci USSR 29 2385-2393 Pokrovskii VN, Kruchinin NP (1980) On the non-linear behaviour of linear polymer flow. 

Zimm, B. H. (1956). Dynamics of molecules in dilute solution viscoelasticity, flow birefringence and dielectric loss. /. Chem. Phys. 24 269-278. 

Figure 3.17 Birefringence as a function of the eigenvalue of the velocity gradient tensor, G, for planar flows generated in a four-roll mill, for dilute solutions of polystyrenes of three different molecular weights in polychlorinated biphenyl solvent. Here G is the strain rate and a the flow type parameter. For planar extension, a — 1 and G = is the extension rate for simple shear, a = 0 and G = y is the shear rate. The different symbols correspond to a values of 1.0 (0)> 0.8 (A), 0.5 (-1-), and 0.25 (diamonds). The curves are theoretical predictions from the FENE dumbbell model, including conformation-dependent drag (discussed in Section 3.6.2.2.2). (From Fuller and Leal 1980, reprinted with permission from Steinkopff Publishers.)...

Isihara, A. and Guth, E. Theory of Dilute Macromolecular Solutions. Vol. 5, pp. 233-260. Janeschitz-Kriegl, H. Flow Birefringence of Elastico-Viscous Polymer Systems. Vol. 6, pp. 170-318. 

---