Abstract: The invention relates to ion-exchange materials comprising a hydrophobic support resin having grafted side chains, wherein the side chains have a surfactant-type structure and comprise ion-exchange groups, and the ion-exchange material is obtainable by radical grafting of the side chains using a radical initiator containing at least one peroxide group. By means of the surfactant-type structure and the specific radical initiator, a regiospecific and particularly uniform arrangement of the side chains on the support resin is achieved which in addition enables outstanding and uniform hydration of the ion-exchange groups. This is expressed, in particular, in improved signal asymmetries for bromide and nitrate.