Electrosyntheses And Characterizations Of Several High-Quality Conducting Polymers

Conducting polymers that possess the properties of metals or semiconductorshave been widely investigated for applications. Electrochemical polymerization hasbeen proved to be one of the most useful approaches for conducting polymersynthesis.This dissertation was focused on the electrosyntheses andcharacterizationsof high-quality conducting polymers mainly obtained from azulene (Az),indole-5-carboxylic acid (ICA), 9-fluorenone (FO) and 9-bromofluorene (BFe) inborontrifluoridediethyletherate(BFEE)anditsmixedelectrolytes.1. Highquality free-standing polyazulene (PAz) films with conductivityof 2.2 Scm-1were synthesized electrochemicallyby direct oxidation of azulene in pure borontrifluoride diethyl etherate for the first time. Structural studies implied that the Azunits remained intact in the isolated 1,3-polyazulene. As-formed PAz film was deepblue in the doped stated and dark brown in the dedoped state. They were bothinsoluble in strong polar solvents such as water and also insoluble in weak polar ornon-polarsolventsuchasacetone acetonitrileandtetrahydrofuran.2. High quality poly(indole-5-carboxylic acid) (PICA) films were preparedelectrochemically by direct anodic oxidation of indole-5-carboxylic acid (ICA) inboron trifluoride diethyl etherate containing additional 80% diethyl ether (EE) (byvolume). PICA films showed good electrochemical behavior and good thermalstability with a conductivity of 10^-2 S cm^-1. The doping level of PICA increasedduring electrochemical growth processes. FT-IR spectroscopy and 1H-NMRspectroscopy indicated that polymerization on occurred at C₍₂₎ and C₍₃₎. FluorescentspectralstudiesindicatedthatPICAwasagoodblue-lightemitter.3. High quality free-standing poly(9-fluorenone) (PFO) films were synthesizedelectrochemically by direct anodic oxidation of 9-fluorenone (FO) in pure borontrifluoride diethyl etherate, which conductivity is 7.8×10^-3 S cm^-1. The oxidationpotential of FO in this medium was measured to be only 1.48 V vs. SCE, which wasgreatly lower than that determined in acetonitrile and dichloromethane. Structural studies showed that the polymerization of FO ring occurred at 2,7-position.FluorescentspectralstudiesindicatedthatPFOisagoodbluelightemitter.4. Poly(9-bromofluorene) (PBFe) with conductivity of 5.4×10^-2 S cm^-1 wasprepared electrochemically by direct oxidation of 9-bromofluorene (BFe) in borontrifluoridediethyl etheratemixedwith15% (byvolume)trifluoroaceticacid(TFA)forthe first time. PBFe films obtained from this medium showed good electrochemicalbehavior and redox stability. FT-IR spectroscopy and ¹H-NMR indicated thatpolymerization occurred at C₍₂₎ and C₍₇₎. PBFe film also showed better thermalstability, compared with polythiophene and poly(para-phenylene). FluorescentspectralstudiesindicatedthatPFOwasagoodbluelightemitter.