Polyelectrolytes in optoelectronics and biomaterials

Polyelectrolyte multilayers are built by the alternating deposition of oppositely charged polymers from solutions onto a substrate. The physical and chemical properties of the multilayers can be controlled by the polyelectrolyte combination, the build up, and the post-build up conditions. The demands of novel material coatings that could be used at the surface of biomedical devices and nano-assemblies that can be used in optoelectronic devices are the trigger for material scientist to explore the new research areas. Polyelectrolyte multilayers are investigated in an aim to fulfill the spectrum of needs ranging from biomaterial to optoelectronic field.;In this dissertation, the thermal elimination of a water soluble poly(xylylidene) precursor to poly(phenylene vinylene) (PPV) is investigated using small and macro-counterion. The aqueous route to PPV is investigated to yield high photoluminescence efficiency at low elimination temperature. The polyelectrolyte multilayers terminated with different heteroatom polycations interaction with cells is investigated for application as a coating for stent.;Fluorescence, UV-vis and Fourier transform infra red spectroscopy were used in order to investigate the optical properties of PPV. PPV elimination was accomplished in air at 80ºC using the macro-counterion poly(ethylene glycol)-4-nonylphenyl-3-sulfoproply ether (PEGNOPS). The route to PPV using PEGNOPS was low on carbonyl content, with a possible contribution from PPV chain separation. The PEGNOPS precursor showed no carbonyl formation on long term storage in contrast to other counterions.;Orthogonal Space Random Walk (OSRW) was performed to understand the exceptionally low temperature (80ºC) required for thermal conversion of PPV precursor containing PEGNOPS. Simulations of the solvent free-system converged for starting points where the backbone was expanded or compressed. The simulation revealed the ability of PEGNOPS to partially pre-order the precursor chain in a conformation that favors the E2 elimination.;The elimination mechanism of poly(xylydiene tetrahydrothiophene) (PXT), precursor to PPV, in assembly in polyelectrolyte multilayers was investigated using FT-IR. PXT assembly with poly(styrene sulfonate) (PSS) and poly(acrylic acid) (PAA) as a polycation were investigated.;The heteroatom effect on polyelectrolyte multilayer assembly was explored. Polycations having the same charge density, molecular weight, and molecular weight distribution were employed for multilayer assembly. The polycations differed only in the heteroatom on which the positive charge resided. The three multilayers terminated with the three different polycations poly(vinyl benzyl trimethyl ammonium) (PVBTMA), poly(vinyl benzyl trimethyl phosphonium) (PVBTMP) and poly(vinyl benzyl dimethyl sulfonium) (PVBDMS) had similar build up characteristics, hydration and wettability. The interaction of the smooth muscle cells (A7r5) with the PVBTMA, PVBTMP and PVBDMS terminated multilayers was investigated. The PVBTMA and PVBTMP are cytophobic to A7r5 cells whereas the PVBDMS multilayer is cytophilic. The effect of UV sterilization of the PVBDMS multilayer on cell interaction was explored.