AQUEOUS-SOLUTION PROPERTIES OF POLYAMPHOLYTES - EFFECT OF THE NET CHARGE-DISTRIBUTION

Viscometric and light scattering studies have been performed on aqueou s solutions of polyampholyte terpolymers based on sodium-2-acrylamido- 2-methylpropanesulfonate (NaAMPS), 2-(methacryloyloxy)-ethyltrimethyla mmonium chloride (MADQUAT), and acrylamide (AM), prepared by an invers e microemulsion polymerization technique. The distribution of net char ges among the chains was varied by adjusting the initial monomer compo sition and the degree of conversion. The effect of this distribution o n the solubility of the samples and on the chain conformation was stud ied. It was found that samples with a narrow distribution of net charg es were soluble in pure water even if the average net charge is small. Addition of salt induces a transition from an extended conformation t o a more compact one, in qualitative agreement with theoretical predic tions. A practically alternated NaAMPS-MADQUAT copolymer prepared by p olymerization in homogeneous solution and with a small average net cha rge shows a behavior quite similar to that of the terpolymers. (C) 199 6 John Wiley & Sons, Inc.