Most of the water-soluble polymers are charged. If the charge on the chain is of one sign – such polymers are called polyelectrolytes(e.g. DNA). If polymers contain charges of both signs – they are called polyampholytes(e.g. proteins). We developed a quantitative theory of conformations and dynamics of these molecules in semidilute and concentrated solutions and of their adsorption at surfaces. Our theory explained a number of unique rheological features of these polymers, such as concentration and ionic strength dependence of viscosity, modulus, and self-diffusion coefficient. We extended the theory to polyelectrolyte gels including the theory of their swelling. We also developed a theory of the way hydrophobicity of polyelectrolytes changes their conformations through the formation of so-called necklaces and the corresponding changes of polymer dynamics. We constructed a theory of adsorption of both polyelectrolytes and polyampholytes on various surfaces. We also determined the key factors that control friction between grafted polyelectrolyte brushes.
We are working on extensions of the scaling theory of polyelectrolytes and polyampholytes to describe complexes and coacervates of oppositely charged polymers and to test theoretical predictions by computer simulations.
- “Theory of Polyelectrolytes in Solution and at Surfaces” by A. V. Dobrynin and M. Rubinstein, Prog. Polym. Sci. 30, 1049-1118 (2005).
- “Polyampholytes” by A. V. Dobrynin, R. H. Colby, and M. Rubinstein, J. Pol. Sci.: Polym. Phys. B42, 3513-3538 (2004).
- “Cascade of Transitions of Polyelectrolytes in Poor Solvent” by A. V. Dobrynin, M. Rubinstein, and S. P. Obukhov, Macromolecules 29, 2974-2979 (1996).
- “Scaling Theory of Polyelectrolyte Solutions” by A. V. Dobrynin, R. H. Colby, and M. Rubinstein, Macromolecules 28, 1859-1871 (1995)