新型水溶性发光聚合物与有机波导增益材料的研究

【作者】 张志坚；

【导师】 韦玮；

【作者基本信息】 复旦大学 ， 高分子化学与物理， 2007， 博士

【摘要】 第一部分随着对共轭聚合物研究不断的深入,水溶性共轭聚合物以其特有的绿色环保性能优势,已受到越来越多研究人员的青睐,成为当今科研领域中的一大研究热点。目前水溶性共轭聚合物材料的制备仍然处于相互激烈竞争的局面,因此,本博士论文第一部分紧密围绕“新型水溶性发光聚合物的研究”这个课题,主要通过选择不同分子进行结构设计与利用简单的合成方法,分别将PEG和PAA的水溶性柔性链引入到芴类共轭刚性的发光聚合物体系中,分别获得了三种新型的功能性芴类发光聚合物材料,从而有效地改善了芴类发光聚合物的光学性质和溶解性,工作主要包括以下三个方面:1、首次成功地将具有荧光性的共轭芴二苯小分子引入到水溶性聚氨酯的分子主链上,从而形成了一种新型聚氨酯功能性复合材料。相对于普通的小分子发光材料来说,该聚合物发光材料在固态时具有不易结晶、为无定形结构以及均匀分布不易产生相分离的特点。所制备的聚氨酯是一种弹性固体,可以溶解在乙醇中,同时又显示出具有半导体性质的荧光性能——最大荧光发射峰在365 nm并且在386 nm处有一个小的侧肩峰,可见它又是一种非常难得的紫外发光聚合物材料。2、首次采用了简单的异氰酸酯反应,成功地将聚芴（PF）作为刚性链段和聚乙二醇（PEG）作为柔性链段,以嵌段方式连结到聚合物分子主链上,从而形成了一种新型的具有刚性链—柔性链结构的嵌段共聚物。由于它合成方法简单,并且能够溶解在很多环境友好型溶剂中,如水、乙醇等等,因此可以将其应用到喷墨打印技术中,此外它还具有丰富多样的自组装形态以及较高的荧光量子效率ca.52%。3、结合近年来提出的通过非共价键作用力来制备聚合物的方法,以侧链上具有羟基的芴苯共聚物为刚性链段,普通水溶性聚合物聚丙烯酸为柔性链段,首次利用共轭聚合物PF3BOH侧链上的羟基与PAA上的羧基之间的氢键进行自组装,得到了一种微观形状可调的新型水溶性发光聚合物纳米材料。所形成的PF3BOH/PAA纳米材料在水中是非常稳定的。通过动态激光散射、扫描透射电子显微镜、荧光发射光谱和紫外可见光吸收谱等技术对它的结构和光学性质进行了表征与分析。第二部分由于所在研究小组承担了国家自然科学基金项目——含氟稀土共轭聚合物波导放大器的研究,作为该基金项目的主要参与者之一,本人还围绕该项目其中一个方向,积极开展了对掺铒有机光波导增益材料的研究,作为本论文的第二部分内容的工作。主要介绍了掺铒光波导放大器（EDWA）的发展历史与应用背景,并着重对有机铒高增益材料的发展历史做了详细的综述,目前该方向碰到的主要困难在于所有掺铒配合物材料的荧光量子效率都极低（～0.01%）,这严重限制了它们的实际应用。我们另辟蹊径,成功地制备了一种新型的有机铒纳米增益材料,通过在高效率的掺铒纳米氧化物表面包覆有机层,从而实现其在有机聚合物材料（溶剂）中具有高溶解性与高稳定性,并且它还具有比普通铒配合物材料高出3个数量级的量子效率,通过Forster理论,计算了OH基团对Er³⁺离子的临界作用距离R₀,从而进一步验证了实验结果,为实现高效率的有机EDWA器件提供了积极的指导意义。更多还原

【Abstract】 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.更多还原