The rise in the production and use of polymers as everyday materials has, for the most part, been due to advances in polymer synthesis allowing the manufacture of a range of materials suitable for many different applications. The current and potential applications of ion-containing polymers, or ionomers, are many and varied. One of the most well-established of these is the use of perfluorinated ionomers as membranes in chlor-alkali cells. Ionic interactions may also be used to modify the propeties of thermoplastics, as in the case of the well-known Surlyn materials which are widely used in packaging applications. Other current applications of ionomers include their use as thermoplastic elastomers, blend compatibilizers and fluid additives such as dispersants. For every existing application, there are a great many potential applications that have yet to be exploited, and with the expansion in ionomer research and applications, there is a need for an account of the field. This book, written by a team of industrial and academic researchers, directed at polymer scientists and chemical engineers, aims to fulfill this need.