Theory of dipolar relaxation in aqueous macromolecular solutions.

Abstract

AbstractRecent advances in dielectric theory are applied to two models representing an aqueous solution of dipolar macromolecules. In one model the water is treated as a dielectric continuum and the macromolecule as a finite‐sized sphere; in the other both components are represented as point dipoles suspended in a background dielectric. The predicted frequency dependences of the complex permittivity in these two cases agree and the validity of the dielectric technique for estimating macromolecular size and shape is established. The model in which water is treated as a dielectric continuum predicts a larger dielectric dispersion in the radio frequency region, which is consistent with the experimental data available for myoglobin. The validity of the Debye formula for relaxation time and the effect of “dielectric friction” in macromolecular solutions are also discussed.