Structural Properties of Ionomers

Abstract

Multiphase materials have increased significantly in importance in recent years. One particular class of such materials is ion-containing polymers or ionomers. By virtue of the combination of covalent hydrocarbon polymer chains and ionic salt species in the same molecule, these materials possess very unusual properties and complicated structures. Several research groups around the world have undertaken the study of ionomers to clarify these structure-property relationships and information is being gained at a rapid rate. It is, therefore, appropriate to review the recent advances in ionomer research. The field of ion-containing polymers is a broad one with applications ranging through electrochemical, petrochemical, mechanical, and bio­ technical venues. Clearly, an exhaustive review of such breadth is beyond the scope of this discussion. Several fundamcntal topical reviews exist (19) and the interested reader is referred to them for background in the various areas. This discussion will focus on materials of low ionic content and hydrocarbon backbone. The areas of classical polyelectrolytes, perm­ selective perfiuorinated membranes, and highly crosslinked ionic cements, therefore, fall outside this review. Several new ionomeric materials have been developed. Both the new materials and the more established ionomers have found new areas of