Synthetic polymers with quaternary nitrogen atoms-Synthesis and structure of the most used type of cationic polyelectrolytes

This paper reviews the advances during the last decade in the synthesis and chemical structures of the important class of charged polymers that bear quaternary ammonium moieties. The synthetic pathways to these polycations are discussed, comprising chain growth and step growth polymerization of suitable cationic monomers as well as chemical transformations of uncharged reactive precursor polymers. Attention is paid to the new methods of controlled polymerization, in particular of controlled radical polymerization. The focus of the review is on linear and branched structures including linear macromolecules with flexible chains, conjugated polymers, block copolymers, statistically branched and dendritic polymers, whereas crosslinked materials are out of the scope. In addition to the structural and synthetic aspects, application properties of the new polymers are noted.