1. Blends of poly(2-hydroxy aniline) and polycaprolactone. 2. Synthesis and characterization of liquid crystalline dopant. 3. Fluorescence of PPV copolymers

The effect of hydrogen bonding in electrically conducting blends was investigated in the first part. Blends of amorphous poly (2-hydroxyethylaniline) (PHEANI) and semi-crystalline polycaprolactone were studied in conjugation with the miscibility, and crystallization effects on the electrical conductivity. No evidence for interaction between the hydroxyl group of PHEANI and the carbonyl group of PCL was found from FT-IR, but UV-measurements showed λ _max shifts in the solid states. It is believed that dominant self-association of PHEANI results in immiscibility of polymer blends. Further, it was found that the cooling rate affects the electric conductivity of blends due to the effect of the crystal size on the percolation pathway.; In the second part, the influence of the liquid crystalline dopant on the conductivity of polyaniline was investigated. Three mesogenic moieties of azobenzene, benzoamide and benzoester group compounds were synthesized for this purpose. These compounds show a nematic and smectic phase at high temperature.; 8-[4-(4′-pentyl) azo benzeneoxy] octylsulfonic acid and 8-[4-(4′-pentoxy) azo benzeneoxy] octylsulfonic acid were shown not to be effective for the doping. The UV-visible spectra of PANI/DBES (4′-benzenesulfonic acid-4-dodecyloxybenzoate) and PANI/DBAS (4′-benzenesulfonic acid-4-dodecyloxybenzoamide) complexes evidence that these two liquid crystalline dopants did induce doping of polyaniline. SAXS measurements show the changes in d-spacing of PANI/DBAS and PANI/DBES complexes at different temperatures. The d-spacing between the smectic and nematic phase was not distinguished. ESR measurements show that the PANI/DBES [1:1] complex has a higher electron density than the PANI/DBAS [1:1] complex. The electrical conductivities of samples decreased with increasing temperature, which is inconsistent with Mott's hopping mechanism. We relate the dependence of the conductivity to the phase transitions.; In the final part, new poly (p-phenylenevinylene) related copolymers containing pyridine, thiophene, biphenyl, and biphenylether groups were synthesized using the Heck reaction. These polymers were shown to be soluble in common organic solvents. They could be spin-cast onto various substrates and produce highly transparent homogeneous thin films without heat treatment. The synthesized polymers showed a gradual approach to blue light emission on incorporation of the pyridine, thiophene, biphenyl, and biphenylether units into the copolymer main chain. In the UV-visible and photoluminescence spectra, the maximum absorption and photoluminescence emission spectra were blue-shifted. Consequently, PPVThV, PPVPyV, PPVBPEV and PPVBPV showed blue emission at 444, 443, 403 and 403 nm, respectively. Also, the PPVPyV-DBSA complex and DBSA showed a lyotropic smectic A type liquid crystal phase.