In another embodiment, the electroactive, energy-storing, highly crosslinked polymer of the present invention is a copolymer, said copolymer comprising two or more different carbocyclic repeat units which are covalently linked via polysulfide linkages; each of said carbocyclic repeat units comprising a carbocycle having from 3 to 12 ring carbon atoms and from 3 to 20 covalent linkages to adjacent