The well developed poly(sulfonium salt) precursor route to poly(arylene vinylenes) (PAV's) has made the PAV family one of the most promising classes of conducting polymers in view of future applications such as electronic devices and electroluminescent materials. The objectives of this dissertation have been to understand (i) the role played by counterions in the polyelectrolyte upon thermal conversion to its fully conjugated polymer, (ii) the doping mechanism and doping induced chemical modification, and (iii) both surface and bulk chemical modification on PAV's. / Poly(sulfonium salt) precursors containing fluoride, chloride, bromide, and acetate were prepared by ion-exchange dialysis of the chloride polyelectrolyte. Thermal gravimetric analysis (TGA) revealed that a much higher temperature, $ca.\ 350\sp\circ$C, was necessary to convert acetate precursor to PPV whereas bromide precursor eliminated at the lowest temperature, $ca.\ 200\sp\circ$C. Infrared spectra suggested that acetate became covalently bound to the polymer backbone rather than forming an ion-pair as in other cases. In situ conductivity measurements on $\rm H\sb2SO\sb4$-doped PPV's showed a marked difference on the limiting conductivity for PPV prepared by different precursors. TG-IR (TGA coupled to infrared) analysis indicated that the products of thermal elimination involved tetrahydrothiophene, the conjugated acid of the anion, and water and implied a different elimination mechanism depending on the anion at various temperature. / Various doping agents, i.e., $\rm H\sb2SO\sb4,\ Fe(ClO\sb4)\sb3{\cdot}6H\sb2O$, and FeCl$\sb3$, were used to dope PPV. IR spectra revealed that irreversible chemical modifications occurred in all cases, i.e., sulfonation, carbonylation, and chlorination. These functional groups were identified by appropriate chemical derivatization, IR, UV-Vis, and ESCA spectroscopies and elemental analysis. Regeneration of modified PPV's via desulfonation and dehydrochlorination has been investigated. A different doping mechanism than the published one has been proposed in the case of $\rm H\sb2SO\sb4$-doping. / Graft copolymerization of various monomers, e.g., iso-butyl vinyl ether (i-BVE), vinyl anisole (VA), and N-vinyl carbazole (N-VC), onto PPV surfaces by means of cationic initiated polymerization has been investigated. Both poly(i-BVE) and poly(VA) were successfully grafted on PPV as confirmed by extensive wash with various solvents and by IR spectroscopy. However, poly(N-VC) was found only in solution. / Demethylation of poly(2,5-dimethoxy-1,4-phenylene vinylene) (PDMPV) using BBr$\sb3$ has been studied. Surface demethylation can be achieved by choosing an appropriate reaction solvent. Functional groups such as ester and urethane linkages have been transferred to PDMPV films through the "OH" handle produced by demethylation. Derivatives were characterized by IR spectroscopy. / Source: Dissertation Abstracts International, Volume: 56-04, Section: B, page: 1985. / Major Professor: Joseph B. Schlenoff. / Thesis (Ph.D.)--The Florida State University, 1994.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77446 |
| Contributors | Wang, Lih-Ji., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 202 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
Page generated in 0.0016 seconds