Conformational and Dynamic Behavior of Polymer and Polyelectrolyte Chains in Dilute Solutions

Abstract

This introductory chapter provides a brief (textbook-like) survey of important facts concerning the conformational and dynamic behavior of polymer chains in dilute solutions. The effect of polymer–solvent interactions on the behavior of polymer solutions is reviewed. The physical meanings of the terms good, ϑ-, and poor thermodynamic quality of the solvent are discussed in detail. Basic assumptions of the Kuhn model, which describes the conformational behavior of ideal flexible chains, are outlined first. Then, the correction terms due to finite bond angles and excluded volume of structural units are introduced, and their role is discussed. Special attention is paid to the conformational behavior of polyelectrolytes. The “pearl necklace” model, which predicts the cascade of conformational transitions of “quenched” polymer chains (i.e., of those with fixed position of charges on the chain) in solvents with deteriorating solvent quality, is described and discussed in detail. The incomplete (up-to-date) knowledge of the behavior of “annealed” (i.e., weak) polyelectrolytes and some characteristics of semiflexible chains are addressed at the end of the chapter.