ABSTRACT
Considerable theoretical and experimental work during the past half century has been devoted to charged polymers [1-9]—macromolecules with ionizable groups. Under appropriate conditions, such as in aqueous solutions, these groups dissociate, leaving ions on chains and counterions in solutions. If the charges on the polymers are all positive or all negative, these polymers are called polyelectrolytes. Common polyelectrolytes are polyacrylic and methacrylic acids and their salts, cellulose derivatives, sulfonated polystyrene, DNA and other polyacids and polybases. If after dissociation of the charged groups the polymers carry both positive and negative charges, they are called polyampholytes. Examples of polyampholytes include proteins, for example gelatin, and synthetic copolymers made of monomers with acidic and basic groups. If these groups are weak acids or bases, the net charge of polyampholytes can be changed by varying the pH of aqueous solutions and at high charge asymmetry these polymers demonstrate polyelectrolyte-like behavior.
