Fluorescent/Phosphorescent Dual Light-emitting Properties Of Waterborne Polyurethane Based On Benzophenone Derivatives

Dual luminescent material which can both emit fluorescence and room temperature phosphorescence is widely used in OLED, sensors, and other aspects of biological imaging due to its excellent and unique luminescent properties. Currently dual luminescent materials are generally divided into metal organic compounds and pure organic compounds in two forms, metal organic complex has high toxicity, readily biodegradable, expensive and other shortcomings. Organic polymer with respect to small organic molecules, have a wider application space and development prospects. Unfortunately, organic polymer which can emit fluorescence and RTP was prepared through blending and ring-opening polymerization. Polycondensation polymer as a common mode of production, but none use this way to synthesize a double luminescent material.In this paper, we synthesized five benzophenone derivatives by nucleophilic aromatic substitution:{4-[(N, N-two-hydroxyethyl)-amino]-phenyl}-phenyl-ketone (K1),{4-[(N, N-dihydroxyethyl)-amino]-phenyl}-(4’-chloro-phenyl)-methanone (K2), bis-(4-((2-hydroxyethyl ethyl) (methyl) amino) phenyl) methanone (K3), bis-(4-((2-hydroxyethyl) (methyl) oxy) phenyl) methanone (K4), bis-(4-((2-hydroxyethyl) (meth) mercapto) phenyl) methanone (K5). By NMR and IR to verify the structure of the molecule, and study their optical properties in solution and in the solid state at room temperature by UV-visible absorption spectra and fluorescence-phosphorescence spectra, K1, K2, K3, K5 launch fluorescence at room temperature, only when 77K, they can emit phosphorescence. We consider these five kinds of benzophenone derivatives access waterborne polyurethane, prepared aqueous polyurethane material can simultaneously emit fluorescence and phosphorescence at room temperature.These five are the use of hydroxy-benzophenone derivatives will be its access to water-based polyurethane, synthesized side chain and main chain type double luminous aqueous polyurethane:For the side chain type aqueous polyurethane, when the amount of access 1%, the quantum yield of up to 80%, showing blue fluorescence in the air, showing a green phosphor in a vacuum. For their study the connection between concentration and light-emitting properties and thermodynamic properties. Found that with increasing concentration, fluorescence and phosphorescence spectra overlap, phosphorescence lifetime in diminishing, the energy gap between singlet and triplet decreases. According to previous work, we proposed to polymerization induced inter system crossing theory -PEX. And test its spectrum and lifetime at to verify the correctness of the theory; For the main chain type waterborne polyurethane, it can show its phosphorescence in the air, and shows another phosphorescence in a vacuum, with the increase of dye concentration, the merger will take place between the two triplet and compare different when benzophenone substituent is a nitrogen atom, an oxygen atom, a sulfur atom and the effects respectively. Thermodynamic properties of K1-WPU and K3-WPU has not changed much, the heat resistance due to the presence of K2-WPU halogen been some improvement. K1 and K2 blends with different polymers, found that can emit room temperature phosphorescence.