Fluorescent Supermolecular Materials Assembled Via Ionic Self-Assmbly And The Anisotropic Property

Polarized fluorescent materials have extensive prospects in electronic and displayapplication due to the efficiency in generating anisotropic emission. The orientation ofthe fluorescent molecules is crucial for the generation of anisotropic fluorescentemission. In this dissertation we use ionic self-assembly strategy to preparefluorescent supermolecular materials. Alignment methods including rubbing, liquidcrystalline organization and photo-alignment are adopted to generate anisotropic filmswith polarized fluorescent emission. The phase behaviour, structure and effect ofalignment condition of the super molecular materials or the anisotropic films areinvestigated in detail. In addition, this work also provides guidelines for theconvenient design of super molecular materials with polarized emission.1. First of all, we prepare a series of liquid crystalline supermolecules with anisotropicfluorescent and optical properties based on ionic bond between acrylic acid group andvarious fluorescent counter ions: stilbene-based dye (STIL) andtetraphenylethylene-based (TPE) dye. The supermolecules exhibited nematic LCphase and the incorporation of fluorescent unit in the liquid crystalline polymershowed different effect on the LC behaviour of the supermolecules depending on thestructure of the fluorescent units. After being spin-coated onto an oriented PVA film,the supermolecules was thermally annealed. The amplifying anisotropy fluorescentemission of the liquid crystalline supermolecules also depends on the chemicalstructure of the fluorescent unit.2. Supermolecular complex PCAMSTIL containing photosensitive unit (cinnamate)and fluorescent unit (stilbene) was prepared by ionic self-assembly (ISA). Thesuccessful formation of the complex was confirmed by nuclear magnetic resonance(NMR) and fourier transform infrared spectroscopy (FTIR). The complex was stable below180℃according to Thermogravimetric analysis (TGA). Irradiated by266nmpolarized laser caused cinnamate group to undergo axis-selective [2+2]photocycloaddition, resulting in an alignment of cinematic group perpendicular to thepolarization direction leading to dichroism value of0.103. The laser-inducedorientation of cinnamate group had a cooperative effect on alignment of thestilbene-based fluorescent unit. So the fluorescence emitted by the oriented film waspolarized and the ratio of anisotropic fluorescence was1.73. Such multifunctionalsupermolecular complex combining photosensitive and fluorescent properties can beconsidered as a promising material for optical and display applications.