Described herein are stable hydroxide ion-exchange polymers. The polymers include ionenes, which are polymers that contain ionic amines in the backbone. The polymers are alcohol-soluble and water-insoluble. The polymers have a water uptake and an ionic conductivity that are correlated to a degree of N-substitution. Methods of forming the polymers and membranes including the polymers are also provided. The polymers are suitable, for example, for use as ionomers in catalyst layers for fuel cells and electrolyzers.