Perfluorocarbon mediated self-assembly of polymers

In Chapter 1, relatively well-defined end/pendent perfluorocarbon-functionalized Polystyrene--Poly(n-butylmethacrylate) (PS-PBMA) blends were prepared by ATRP and other synthetic methods to study the polymer self-assembly promoted by Fluorophilic Interactions (FI), which in theory can be treated as an extended instance of solvophobic effects in bulk state. Microscopic characterizations such as Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) show micro-phase separated morphology with domains in the nanometer length scale for both type of polymer blends when a certain "critical perfluorocarbon concentration" is met, which is in principle supported by macroscopic characterizations such as DSC and optical clarity measurements. For the end-functionalized blends, lower polymer molecular weight and longer perfluorocarbon chain improve phase compatibility. Similarly for the pendent-functionalized blends, higher perfluorocarbon mole percentage generates more miscibility. However, possibly due to the excluded volume effect, the compatibilizing effect of perfluorocarbon end-groups is about 5-6 times higher than that of the perfluorocarbon pendent-groups. Qualitative "phase diagrams" for such perfluorocarbon mediated systems were constructed.;In Chapter 2, we applied the perfluorocarbon-mediated polymer self-assembly system to single-layer polymeric OLED devices. The EL spectra clearly indicated a highly efficient energy transfer process in the Rf-PPVO/(tpy)2Ir(acac)/Rf-PVK system and only partial energy transfer in the Rf-PPVO/(pq)2Ir(acac)Rf 2/Rf-PTPA system. The device efficiency of the non RF emitter system is comparable to the corresponding conventional random copolymer system, suggesting the FI induced block copolymer like morphology is possibly a useful architecture for similar low-cost single-layer OLED devices. However, the devices with perfluorocarbon-functionalized emitters were generally rather poor in efficiencies. We speculate that this is due to the unfavorable emitter aggregation caused by FI. As a general nano material self-assembling technique, FI has great potentials in polymer-based opto-electronics research.