In this paper, we reported a two-step technique for fabrication of PMMA/Ag nano coreshell structure with well-established processing parameters and an ease control.Firstly,we fabricated the monodisperse PMMA nanospheres with a diameter of about 170 nm by emulsifier-free emulsion polymerization.Then,we modified the PMMA nanospheres surface with(3-methacryloxypropyl) trimethoxysilane(MATS) and(3-mercaptopropyl) trimethoxysilane(MPTMS),resulting in a uniform sulfhydryl(SH)-group modified outlayer and Ag nanoparticles further grew on the modified surface of PMMA nanospheres with an effective interaction between sulfhydryl(SH) groups and Ag+.In doing so,finally we synthesized PMMA/Ag core-shell composited nanoparticles.The structure of the synthesized sample was investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM) and UV-Vis extinction spectra.The results indicate that the well-dispersed PMMA/Ag core-shell nanoparticles with uniform particle size distribution were successfully fabricated using this improved technique.
Nanoparticles modified with aminopropyl group were prepared by a single-step electrospray process and used as a pseudo-stationary phase for the separation of anions, (e.g., organic acids in capillary electrophoresis). The nanoparticles form a uniform suspension which is stable in a buffer without adding other stabilizer. The amino containing nanoparticles have significant impact on the electro-osmotic flow (EOF) of the system, which, in turn, affects the overall separation of other analytes in this system. For example, five organic acids, which were not all separable in zone electrophoresis, were fully resolved in the presence of the nanoparticles in a wide range of pH. Various experimental parameters that are related to the electrophoresis including EOF, pH, organic modifier, voltage, concentration of the running buffer and concentration of the nanoparticles have been investigated. The repeatability of the migration time and peak area in this system are better than 5% for both inter- and intra-day evaluation.
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