| A surface-bound polymer, poly(2-vinylnaphthalene-alt-methacrylic acid)(P(2VN-alt-MA)), was used to sensitize a surface-bound chromophore, pyrenebutyric acid (PBA), where the surface was zeolite-Y. Two solvent systems were used, tetrahydrofuran and methanol. The quantum efficiency of PBA sensitization ({dollar}chi{dollar}) was estimated using the deconvoluted fluorescence and excitation spectra. The most efficient sensitization ({dollar}chi{dollar} = 0.41) was observed with zeo/poly/PBA/CH{dollar}sb3{dollar}OH, where the polymer was adsorbed before the PBA. The choice of solvent affected the appearance of the fluorescence spectra, but did not systematically affect the enhancement factors or the quantum efficiencies. The order of addition of the polymer and PBA to the zeolite strongly affected the photophysics of the system.; Configurations of polymer chains adsorbed to a nonpenetrating surface were modeled using a Monte Carlo technique in which the solvent strength, {dollar}phi{dollar} (= -{dollar}varepsilonsb1{dollar}/kt), and the energy of adsorption, {dollar}lambda{dollar} (= -{dollar}varepsilonsb2{dollar}/kt), were varied. According to these calculations, the polymer chains essentially flatten out on the surface at adsorption energies of {dollar}lambda{dollar} = 0.6, at all solvent strengths. Using the same ensemble of coils, fluorescence decay curves were calculated by placing deep energy traps randomly on the chains and allowing electronic energy transport (EET) to occur between adjacent polymer segments. As the adsorption energies increased, faster decay curves were observed. The conformational and kinetic data reflected changes in the polymer configurations as the solvent strength and adsorption energies were varied in the presence of a surface. |
