Synthesis and characterization of chloro and bromo substituted p-phenylene vinylene homopolymers and alternating copolymers

Halogen-substituted poly(p-phenylene vinylene) (PPV) and copolymers containing halogen-substituted PPV were chemically synthesized via Wessling and Wittig routes, respectively. FTIR, 1H NMR, UV–vis and fluorescence spectroscopies and electrochemistry were used to characterize the polymers. The absorption and photoemission spectra show that addition of halogen causes a red shift in both absorption and emission properties for the halogen-substituted PPV and for the segmented copolymers in relation to the non-substituted polymers. The electron affinity (EA) and the ionization potential (IP) show that the halogens bonded to the ring do not change the HOMO and LUMO edges, but the copolymers present higher values for the IP and lower values for the EA with respect to the homopolymers.