New Water-soluble Light-emitting Polymers And Organic Waveguide Gain Materials

Part 1With rapid development of research on conjugated polymers,water-soluble conjugated polymers attracted many interests of scientists,and became a focus of current scientific fields owing to its environment-friendly advantage.Nowadays the preparation of water-soluble conjugated polymer was facing intense competition. Therefore,the first part of my Ph.D dissertation enclosed the subject of "Study on Novel Water-Soluble Light-Emitting Polymers" by selecting designs for different molecular structures,and using simple synthetic methods to graft the flexible water-soluble chain structures of PEG and PAA into the fluorene-based conjugated rind light-emitting polymer systems.Three novel functional fluorene-based light-emitting polymer materials were synthesized and their optical properties and solubility were improved.Research of this part included three contents as below:1.We succeeded in grafting the small-molecule structure of the light-emitting diphenyl-fluorene into the main chains of water-soluble polyurethane(PU) for the first time and a novel PU of the complex functional material was prepared.Compared to common small-molecule light-emitting materials,the prepared light-emitting PU was hard to crystallize and had no phase separation in solid state with the ability of the amorphous structure and proportional distribution.The prepared PU was an elastic solid,which could dissolved in ethanol,and it exhibited strong deep purple fluorescence at the peak of 365 nm along with a shoulder at 386 nm as a thin film. Obviously,the prepared PU also was a kind of uncommon ultraviolet-emitting polymer materials.2.A novel water-soluble rod-coil block copolymer was designed and prepared successfully via the facile isocyanic acid polycondensation method using polyfluorene (PF) as rod segment and polyethylene glycol(PEG) as coil segment in the main chain for the first time.As its easy synthesis and good solubility in environment-friendly solvents,such as water,ethanol and so on,it could be well applied into ink-jet-printing technique.And it also possessed self-assembling morphologies and took on a high fluorescent quantum efficiency ca.52%.3.Recently there were many research reports on preparing polymers via non-covalent bond.Using polyfluorene-co-phenylene with hydroxyl-capped alkoxy side chains(PF3BOH) as rod segment and poly(acrylic acid)(PAA) of the common water-soluble polymer as coil segment,we successfully prepared a kind of novel water-soluble shape-regulatable light-emitting nanomaterials for the first time by self-assembly from hydrogen bonding between hydroxy-capped groups on the side chains of PF3BOH and the carboxy groups on PAA side chains.The prepared PF3BOH/PAA nanomaterials were quite stable in water for no precipitate was observed after several weeks.Transmission Electron Microscopy(TEM) and Dynamic Laser Light Scattering(DLS) were used to confirm the morphology of the PF3BOH/PAA nanomaterials.Their optical properties were investigated and showed the similar optoelectronic properties with PF3BOH solid film except aggregation.Part 2Because our group was carrying out a project for National Natural Science Foundation of China,with the subject of "Research on EDWAs of fluoride conjugated polymers",as one of main participators,I also did some research work on "Study of High-Powered Materials for Organic EDWAs" for the project as the second part of my Ph.D dissertation.This part mainly focused on the developing history and the application foreground about EDWAs,and particularly summarized the developing history of high-powered materials for organic EDWAs.One of the key problems in this field was that all the erbium doped organic materials had extremely low fluorescent quantum efficiencies,only about 0.01%,which terribly limited their application. However,we found another way to make a novel high-powered erbium doped organic nanomaterial,by which the organic layer fully enwrapped the surface of the erbium doped oxide materials,and it could be well dissolved in organic polymer materials or solvents.Further more,it also showed better fluorescent quantum yield,almost 1000 times higher than that of the common erbium organic complexes.Based on the fluorescence resonance energy transfer theory,the F(?)rster critical distance R₀ of the interaction from OH group to Er³⁺ was calculated to further confirm the data from experiments.In a word,our results provided solid evidences in making highly efficient organic EDWAs.