A. G. Ogston

On the Transport of Compact Particles Through Solutions of Chain-Polymers

The problem is discussed of providing a theoretical explanation for the empirical equation of Laurent, Bjork, Pietruszkiewicz & Persson (1963) which relates the relative retardation of the sedimentation of compact particles in solutions of hyaluronic acid to the radius of the particle and the concentration of hyaluronic acid. From published and original data, the same relation is shown to apply also to sedimentation and diffusion in solutions of a number of linear and branched chain-polymers. Of several approaches to the problem, only one, based on the stochastic model of diffusional migration, yields the empirical relationship, and predicts a value of the numerical constant close to that observed. This treatment is shown to apply to other forms of migration, including the case where the chain-polymer is itself migrating. The theory is tested by calculation, from migration data, of the effective radii of the polymer chains. The results are consistent and comparable with values deduced from equilibrium experiments.