Preparation And Characterization Of Inorganic And Organic Fluorescence Compound/Polymer Nanocomposite Materials

As the inorganic / organic composite nano-materials in the field of one of With the development of nano-science technology and its increasing improvement, exploiting composite nanomaterials by blending process has become a remarkable area in materials science, physics, chemistry and so on. In which the preparation of inorganic / organic nano-composites has received widespread interest, because it combines the character of nano-particles, inorganic and organic properties together to be identified as a kind of new functional materials. Therefore, research on inorganic / organic nano-composites will be a highly innovative and challenging area. As an important part of inorganic / organic nano-composites, Inorganic nanoparticle / polymer composite fibers and particles have broad prospects in both practical application and scientific research. Electrospinning is an important method in the preparation of ultra-fine fibers in modern times, nanofibers prepared with this technique have many promising advantages such as multi-dimensional nature, versatility, simplicity, low cost, continuity and so on.In the second chapter of this thesis, we first prepared pure PS nanofibers using electrospinning technique. PS was employed as raw materials and DMF was the solvent. The final result demonstrates that with the constant increase of solution concentration, the electrispinning products show different morphologies, changing from irregular micro / nano-spheres to bead-on-string fibers(coexistence of fibers and partricles), and finally all fibers. With the enhancement of electrospun voltage, the diameter of nanofivers shows a trend of becoming smaller. We have foundd the best condition of preparing fibers: concentration of PS/DMF solution is 15wt%, electrode spacing is 16 cm, electrospun voltage is 15 KV. Under this condition, we collected microspheres with average diameter of 550 nm and the diameter is also evenly distributed. On this basis, we synthesized P4VP and TPPA/P4VP composite nanofibers. We discussed adequately on their preparation method, the condition selection, the morphology of resultant products and their fluorescent properties. 10wt% is proved to be an desired concentration to obtain nanofibers with good morphology. With the add of TPPA, the diameter of composite nanofibers become more uniform. Pure TPPA and TPPA/P4VP composite nanofibers all show emission peak at 650nm. When TPPA/P4VP composite nanofibers were placed for 10 days, the emission peak was still observed to be at 650nm. We can conclude that electrospun products have stable fluorescent property, their fluorescent property is well preserved and there is no effect from electrospinning process.In the third chapter, we prepared CdSe / PS composite fibers and investigated the morphology and fluorescent property of electrospun products. The result indicates that the increasing amount of CdSe quantums dots leads to bending fibers with reduction of diameter. The composite fibers show stable fluorescent properties. Compared with electrospinning solution, there is no change of emission peak from one-component and two-component fluorescent nanofibers. When placed for a month, the position of emission peak was remained, only with a weakness of emission intensity. There is no interference between two bends in two-component electrospun nanofibers. CdSe nanoparticles were observed to be homogeneously distributed in PS matrix without occurrence of obvious aggregation.In the fourth chapter, we focus on the synthesis and characterization of inorganic/organic nanospheres. First, we investigate electrospun micro/nanospheres with PS as raw materials. The result reveals that with the increase of solution concentration, the microspheres show different morphologies from irregular microspheres to depressed micro/nanospheres and finally bead-on-string fibers. The morphology of electrospinning products can be also influenced by electrospinning distance. If the electrospinning distance is as close as 5cm, the solvent can not be completely volatile as microspheres arrive at the collector. As a result, there will be irregular depressed spots on the surface of electrospun microspheres. Finally, the best condition for micro/nanospheres is that: the solution concentration at 20wt%, electrospinning distance at 15cm, electrospinning voltage at 15kv. The prepared microspheres under this condition is with average diameter of 1350nm.On the basis of the above work, we have prepared PS and TPPA / PS light-emitting composite micro / nanospheres. We explore the preparation condition and the florescent stability of electrospun products. When the concentration of pure PS electrospinning solution is adjusted to be 20%, the resultant microspheres are with desired morphology. At the same time, the increasing addition of TPPA ultimately leads to a reduction of microspheres'diameter and the diameter polarization is obvious. The fluorescent property of electrospun product is also stable. When left for 20 days, there is no obvious shift of the emission peak of micro/nanospheres, which lays a solid foundation for their future applications.In the fifth chapter, we prepared CdSe / PS light-emitting composite micro / nanospheres and discussed product appearance and the fluorescent performance. With the increase of CdSe quantum dots, the average diameter of micro / nanospheres becomes smaller. In addition, the fluorescent property of micro/nanospheres is promising. Compared with electrospinning solution, the emission peak of one-component and two-component micro/nanoshperes does not show any change. Even when left for one month, only a weakness of emission intensity is observed, there is no shift of emission peak, also no interference between two kinds of CdSe quantum dots. Measured by TEM, CdSe quantums dots are well distributed in PS matrix without obvious aggregation.The exploration and research in this thesis provide new approach and new way for the design and preparation of novel inorganic / organic fluorescent nanocomposites. The stable fluorescence and other special qualities can lay solid foundation for their future applications.