Design And Preparation Of Metal Nanoparticle Based Polymer Composites

Organic/inorganic nano hybrid materials have shown great potential application in the next-generation nonvolatile memory due to the advantages of high flexibility, ultrafast response, low power consumption, multi-dimension for data storage, miniaturization, ease of processing and controllability. However, there is deviation in the memory test as a result of the agglomeration of metal nanoparticles. Hence, exploring an effective way to avoid the problem is very essential. In this thesis, Yolk-Shell nanorattles encapsulating and brush loading were utilized to synthesize hairy Au@air@PVAn-g-PANI hybrid nanorattles and PVK brush loaded Ag nanoparticles, respectively. Meanwhile, we investigated their basic structures, and explored the nonvolatile memory performance and memory mechanisms of the former one. This thesis was divided into these three chapters, as follows:In the first chapter, the device structure and working mechanism of the resistive memory materials, as well as the progress of nano-materials for memory were reviewed.In the second chapter, Au@SiO2@PVAn nanospheres were prepared by distillation-precipitation polymerization. Surface-initiated oxidative graft copolymerization of aniline from the Au@SiO2@PVAn nanospheres, produced the Au@SiO2@PVAn-g-PANI nanospheres. HF etching of the hairy Au@SiO2@PVAn-g-PANI core-double shell nanospheres removes the inorganic silica inner-shell and gives rise to hairy Au@air@PVAn-g-PANI hybrid nanorattles. The hybrid nanorattles can be integrated into an electrically insulating poly(vinyl alcohol)(PVA) matrix. The Al/Au@air@PVAn-g-PANI+PVA/ITO-coated polyethylene terephthalate)(PET) flexible device, with a turn-on voltage of-2.0V and an ON/OFF state current ratio of more than104, was fabricated. This device can be switched to the ON state under a negative electrical sweep, and also can be reset to the initial OFF state by a reverse (positive) electrical sweep. The memory behaviors of the flexible device were almost unchanged under the bending test.In the third chapter, narrowly dispersed PVK core with the size of235nm was first synthesized by emulsion polymerization. The Ag-NPs were successfully generated in the PVK brushes and the resultant material showed good dispersion in the deionized water. The TEM images reveal that the average diameter of the loaded Ag NPs is about4nm. Using the PVK brushes which have loaded Ag NPs as the nanoreactors, the Ag NPs were generated again in the PVK brushes. The TEM images reveal that there are more Ag NPs dispersed on surface of the PVK brushes. The structure characterization resultant and optical properties of the Ag NPs-loaded PVK polyelectrolyte brushes were also report in this chapter.