Conclusion

Synthetic polyampholytes are very close to proteins by structure and behavior. They have unique electrochemical, hydrodynamic and conformational properties due to distribution of acidic and basic monomers along the chain, e.g. random, alternating, graft, branched, and block sequences. Polyampholytes are divided into annealed, quenched and betaine type series. Synthesis of polyampholytes comprises mostly the radical initiated copolymerization of acidic and basic monomers in bulk, solution, emulsion, and suspension. The chemical modification of preformed polymers includes acid and base hydrolysis, quaternization, oxidation, etherification, esterification, enzyme-and photo activation etc. The synthetic conditions including the kinetics and mechanism of copolymerization determine the composition and microstructure of final products and are controlled by formation of hydrogen and salt bonds between monomers and solvents, by addition of simple salts, surfactants, catalysts etc. The reactivity of acid and base monomers can be regulated through formation of monomer complexes stabilized by hydrogen and salt bonds. The different distribution of acidic and basic monomer units was clearly shown for copolymers synthesized by radical copolymerization and chemical modification. For instance, equimolar copolymers of MAA and DMAEM obtained by radical copolymerization and acid and base hydrolysis differ in microstructure, solubility, isoelectric points and apparent ionization constants. Novel approach to design polymeric betaines or so-called zwitterionic polyampholytes having specific structure due to length of flexible spacer groups and replacement of oppositely charges in either main chain or side chain accompanied by the presence of hydrophobic tails (zwitterionic polysoaps) has recently been developed.