Inclusion of the cation iodonium (I-3(+)) into the structure of poly(N-vinylcarbazole)

Iodine is an usual doping agent used in order to improve the conductivity o f insulator polymers with either aromatic and conjugated double bonds in th eir structure. This paper evidences the action of the cation iodonium on th e conductivity of poly(N-vinylcarbazole) (PVK) and nitrosilated-PVK (PVK-NO ). The cation is introduced via bis-pyridine-iodonium tetrafluoroborate sal t (IPYBF4) in both polymers yielding PVK-IPY-P and PVK-NO-IPY-P complexes, respectively, with a 1: 1 ratio (carbazolyl/ iodonium) in each. The complex extends the absorption band in the UV-Visible region and its IR spectrum s hows characteristic bands. Both inter- and intra-molecular distances were m odified in the polymer by the presence of iodonium as it is manifested by W AXS experiments. The thermal behaviour of the complex was studied by simult aneous thermogravimetry and differential thermal analysis being quite diffe rent from that of PVK. The polymer-IPY complex is stable till 200 degreesC at which point the pyridine ligands loss takes place and results in a new s tructure of PVK-I+ which is stable till 380 degreesC and then is suddenly d egraded. Elecrical conductivity of the complex improves with respect to tha t of PVK, but it does not overcome the semiconducting level achieved with o ther dopants. (C) 2001 Elsevier Science Ltd. All rights reserved.