EFFECTS OF INTERCHAIN CROSSLINKING BY ALKYL DIHALIDES ON THE ELECTROCHEMICAL PERFORMANCE OF NANO-SCALE POLYPYRROLE FILMS

Disclosed are the electrochemical effects of crosslinking polymer chains in nanoscale polypyrrole films with aliphatic ethyl (Ppy-Et), propyl (Ppy-Pr), and butyl (Ppy-Bu) groups were investigated. The films are synthesized by pulsed-electrodeposition of polypyrrole followed by a crosslinking reaction with an alkyl dihalide (dibromoethane, dibromobutane, or dibromopropane) in methanol. By changing the length of the alkyl-dihalide crosslinker, it was shown that one can adjust the properties of the polypyrrole films to achieve properties not typical for polypyrrole. The resulting materials exhibit valuable properties in two areas: (1) excluding anions from transport through the polymer, allowing for the creation of cation-selective membranes using polpyrrole crosslinked with ethyl (2 carbon) crosslinker molecules and (2) enhancing the specific capacity by >50% relative to the uncrosslinked polymer using propyl (3 carbon) crosslinker molecules. These materials have potential value for energy storage, electrochemical desalination, membrane separations, and chemical sensors.