A structured organic film (SOF) is disclosed. The structured organic film also includes a plurality of segments, a plurality of linkers, and optionally a plurality of capping segments, where at least one or more capping segments may include at least one cationic species. Implementations of the structured organic film (SOF) include where all of the plurality of linkers are bonded to the plurality of segments. A concentration of ionic capping segments in the SOF is from about 0.1 to about 5.0 molar equivalents of ionic capping segments as compared to a concentration of nonionic segments in the SOF. An ion-exchange membrane may include the structured organic film (SOF).