Ionomer

An ionomer (/ˌaɪˈɑːnəmər/) (iono- + -mer) is a polymer that comprises repeat units of both electrically neutral repeating units and a fraction of ionized units (usually no more than 15 mole percent) covalently bonded to the polymer backbone as pendant group moieties. This means that most ionomers are copolymers of the neutral segments and the ionized units, which usually consist of carboxylic acid groups.