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Thermal-induced Alternation in Size Distribution of Gold Nanoparticles Characterized by Differential Mobility Analyzer
ALICE CHINGHSUAN CHANG, Fang-Hsin Lin, Industrial Technology Research Institute
Abstract Number: 27
Working Group: Instrumentation and Methods
Abstract
Nanoparticles have been widely considered because of its advantages involving high surface area and catalycity. Accompanied by the great growth in the research and fabrication of nanoparticles with size of sub-20 nm, it is getting more important to correlate the size and performance of nanoparticle. Commonly-selected techniques for the size measurement are transmission electron microscopy (TEM) and differential mobility analyzer (DMA), and the later additionally provides the size distribution of sample so that the statistic information could be directly obtained. The gas-phase DMA calculates the diameter of nanoparticle based on its electrophoretic characteristic and its main drawback is the larger detected size compared with the TEM results, which contributes to the inclusion of the non-volatile components in aerosol measured by DMA. In this study, a tube furnace was equipped with DMA for the removal of the organic, burnable impurities in the aerosols so that the composition of the non-volatile materials could be reduced. The reference gold nanoparticle with diameter of 10 nm (NIST-8011) was chosen and different heating temperatures were used for the size monitoring. At the temperature of 800 ˚C, most of the organic surfactants were flamed and the noise signals disappeared from the size distribution collected by DMA. On the other hand, the mean value and number concentration of gold nanoparticles showed little change. The comparable size of gold nanoparticle independent of heating temperature were connected to the reshaping and charging of the nanoparticle induced by the thermal treatment. Conclusively, the influence of the sample preparation and parameter selection on size measurement was illustrated and the correlation of DMA and TEM results were made in this work.