【作者】 徐飞；

【导师】 马向阳； 杨德仁；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2007， 硕士

【摘要】 通过在聚合物中引入纳米粒子形成的纳米粒子/聚合物复合材料，一方面可以利用聚合物分子链之间的排斥作用有效防止纳米粒子的团聚，另一方面聚合物材料可以为纳米粒子提供基体，利用聚合物材料加工性能良好等优点可以制备各种器件，因而这种复合材料有着良好的应用前景。本文在纳米粒子/PMMA复合材料的制备及性质研究方面做了一些探索，取得了如下主要结论：1．利用高温热注入法(Hot injection)，分别以三辛基氧化膦(TOPO)和油酸(OA)作为包覆剂制备了CdSe纳米粒子；用溶胶-凝胶法制备了ZnO纳米粒子。在此基础上，用共混法制备了CdSe/PMMA和ZnO/PMMA纳米复合材料。2．CdSe/PMMA复合材料的荧光光谱(PL)表明：TOPO包覆的CdSe/PMMA复合材料的发光峰很宽，表现为中心波长为478nm、半高宽为150nm左右的宽化的单一峰；而OA包覆的CdSe/PMMA纳米复合材料除了在510nm附近有发光峰以外，在400nm附近还有发光峰，它与PMMA有关。上述结果表明CdSe/PMMA纳米复合材料的发光与CdSe纳米粒子的包覆剂有关。3．OA包覆的CdSe/PMMA纳米复合材料在激光持续辐照下，PL谱上表现出与PMMA有关的发光峰不断减弱、而与纳米粒子有关的附近的发光峰不断增强且稍许红移。TOPO包覆的CdSe/PMMA纳米复合材料在激光持续辐照下，单一的发光峰也表现出红移。我们把这一现象的起因归结为CdSe纳米粒子的表面修饰在激光辐照下发生变化以及CdSe纳米粒子与PMMA基体之间存在能量转移。4．PL谱表明：本文中所制备的ZnO纳米粒子380nm附近的近带边发光弱于550nm附近与深能级相关的缺陷发光，而ZnO/PMMA纳米复合材料在380nm左右的发光却强于550nm左右的发光。上述现象表明：PMMA基体钝化了ZnO纳米粒子表面的缺陷。5．将CdSe/PMMA纳米复合材料拉制成光纤，它的透光率与未掺杂的PMMA光纤相比，在可见光的长波波段(600nm以上)可以相比拟。随着传输光波长的减小，复合材料光纤的光通过率比未掺杂的PMMA光纤材料下降得更快，这是由于部分波长较短的光被CdSe纳米粒子吸收。用小于CdSe纳米粒子发光波长的光做光源可以激发CdSe纳米粒子发光，使得CdSe/PMMA纳米复合材料光纤成为有源光纤，这一性能将有可能在光增益器件方面有潜在应用。更多还原

【Abstract】 Elaboration of nanocomposite system by embedding of nanoparticles into polymeric matrix can afford a new class of polymeric materials which combine the properties of nanoparticles with the processability and flexibility of organic polymer matrix. In this thesis, CdSe/PMMA and ZnO/PMMA nanocomposites were prepared and their properties were preliminarily explored. The main results achieved in this thesis are listed as below:1. The TOPO and OA modified CdSe nanoparticles were synthesized by a hot injection method. ZnO nanoparticles were prepared by a sol-gel method. Using such synthesized nanoparticles, the nanoparticles/PMMA nanocomposites were prepared by a blending method.2. Photoluminescence (PL) spectra show that there is only one broad luminescence band of the TOPO-modified CdSe/PMMA nanocomposite, which peaks around 478nm; while there are two luminescence bands peaking around 400 and 510 nm respectively for the OA-modified CdSe/PMMA nanocomposite, which are respectively related to PMMA and CdSe nanoparticles. It is suggested that the PL of CdSe/PMMA nanocomposites is dependent on the modification of the CdSe nanoparticles.3. With the extension of laser radiation, for the OA-modified CdSe naoparicles/PMMA nanocomposite, its PL spectra are manifested as the weakening of PMMA-related peak and the strengthening and slight red-shift of nanoparticles-related peak; while for the TOPO-modified CdSe naoparicles/PMMA nanocomposite, the broad PL band also exhibits a red-shift. Such phenomena are preliminarily ascribed to the change of surface modification of nanoparticles by the laser radiation and energy-transfer between the PMMA matrix and nanoparticles.4. PL spectra show that the near-band-edge (NBE) emission is weaker than the defect-related emission for the stand-alone ZnO nanoparticles; while the NBE emission is stronger than the defect-related emission for the ZnO nanoparticles incorporated into the ZnO/PMMA nanocomposite. This means that the PMMA can well passivate the defects of the ZnO.5. Two fibres were drawn from PMMA and CdSe/PMMA nanocomposite respectively. The light transmissions at the wavelength larger than 600 nm are comparable for the two fibers. However, for the shorter wavelengths, the light transmission of the fiber derived from the composites is reduced faster than that of the fiber derived from PMMA, due to that the CdSe nanoparticles substantially absorb the light. Moreover, if using the light with appropriate short wavelength as the optical source for the fiber, the CdSe/PMMA nanocomposite fiber becomes an active one, which could find application in the optical gain devices.更多还原