Anisotropic counterion polarizations and their dynamics in aqueous polyelectrolytes as studied by frequency-domain electric birefringence relaxation spectroscopy

Transient electric birefringence of two small DNA restriction fragments of the same molecular weight

“…This result is in agreement with other investigations, which have also concluded that a slow induced dipole mechanism must be important for the orientation of DNA in an electric Most investigators have assumed that the slow induced dipole must be parallel to the long axis of the DNA molecule^. '^*^* Recently, however, 00-kubu, 44 studying the frequency-dependent electric birefringence of sonicated calf thymus DNA, found evidence for two slow induced polarizabilities, one parallel and one perpendicular to the long axis of the macromolecules. These results are in agreement with the earlier studies of S t e l l~a g e n ,~~ who found that the reversing field behavior of calf thymus DNA could only be explained by the existence of two perpendicular slow induced polarizabilities.…”

“…A perpendicular dipole moment would seem to be unlikely because of symmetry; however, curved DNA molecules such as fragment 12A are asymmetric and could have a transverse dipole moment. Slow induced dipole moments in the perpendicular direction have been proposed by Ookubu et al 44 to explain the high frequency electric birefringence dispersions observed for DNA. Using the equations of Tinoco and Yamaoka, 24 the reversing field transients observed for fragments 12A and 12B can be modeled by two slow orthogonal polarizabilities, as shown in Figure 12.…”

Frequency Behavior of the Electro-optical Effect from Colloid Particles in Polyelectrolyte Solutions with Counterion Mixtures

“…Three relaxation modes with different relaxation times are observed in the dispersion curve of oxide suspension, stabilized by polyelectrolyte adsorption. In the present work, in analogy with the frequency-domain electric birefringence spectra of polyelectrolyte solutions (13), the electric light scattering effects of stabilized suspension with different frequency of relaxation are denoted RF, LF, and HF effects, i.e., rotational, low-and high-frequency effects (Fig. 1).…”

“…The observed dependence of the electro-optical effect on The unessential change of the HF relaxation in stabilized suspensions in comparison to the HF relaxation in aqueous the mixture composition is analyzed according to the theoretical predictions that the degree of binding of the less bound oxide suspension implies that the HF effect in the colloidpolymer system is due to free counterion polarization. The monovalent counterions increases and that of the more bound divalent counterions decreases with increasing correspond-HF relaxation in semidiluted polyelectrolyte solutions has been interpreted in (13) as a result of the motion of loosely ing equivalent fraction of the counterion in the mixture (21).…”

Electric Properties of Carboxymethyl Cellulose

“…[62] a principally different conclusion is drawn: the electric polarizability of CMC coated particles is due to the condensed counterions. The interpretation is based on the lowfrequency shift of the dispersion curves employing the Schwarz's equation 1/2 = 4DiL 2 and using the literature value Di = 6 10  11 m 2 /s [64] for bound Na + in a CMC solution; the CMC chain is assumed to be a straight polyion with length L = 505 nm (equal to the contour length Lc of CMC with M = 250 kg/mol). Then, accepting that the estimated 1/2 = 300 Hz is close to the experimentally obtained 1/2  3 kHz, the authors conclude that the orientation of CMC coated particles in the electric field is due to condensed counterions polarization along the adsorbed polyelectrolyte chains.…”