Noroozi Monir, Radiman Shahidan, Zakaria Azmi, Soltaninejad Sepideh
School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia.
Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
Nanoscale Res Lett. 2014 Nov 29;9(1):645. doi: 10.1186/1556-276X-9-645. eCollection 2014.
Silver nanoparticles were successfully prepared in two different solvents using a microwave heating technique, with various irradiation times. The silver nanoparticles were dispersed in polar liquids (distilled water and ethylene glycol) without any other reducing agent, in the presence of the stabilizer polyvinylpyrrolidone (PVP). The optical properties, thermal properties, and morphology of the synthesized silver particles were characterized using ultraviolet-visible spectroscopy, photopyroelectric technique, and transmission electron microscopy. It was found that for the both solvents, the effect of microwave irradiation was mainly on the particles distribution, rather than the size, which enabled to make stable and homogeneous silver nanofluids. The individual spherical nanostructure of self-assembled nanoparticles has been formed during microwave irradiation. Ethylene glycol solution, due to its special properties, such as high dielectric loss, high molecular weight, and high boiling point, can serve as a good solvent for microwave heating and is found to be a more suitable medium than the distilled water. A photopyroelectric technique was carried out to measure thermal diffusivity of the samples. The precision and accuracy of this technique was established by comparing the measured thermal diffusivity of the distilled water and ethylene glycol with values reported in the literature. The thermal diffusivity ratio of the silver nanofluids increased up to 1.15 and 1.25 for distilled water and ethylene glycol, respectively.
采用微波加热技术，在两种不同溶剂中，于不同辐照时间成功制备了银纳米颗粒。在稳定剂聚乙烯吡咯烷酮（PVP）存在的情况下，银纳米颗粒分散于极性液体（蒸馏水和乙二醇）中，无需任何其他还原剂。利用紫外可见光谱、光热电流技术和透射电子显微镜对合成的银颗粒的光学性质、热性质和形态进行了表征。结果发现，对于这两种溶剂，微波辐照的影响主要在于颗粒分布，而非尺寸，这使得能够制备出稳定且均匀的银纳米流体。在微波辐照过程中形成了自组装纳米颗粒的单个球形纳米结构。乙二醇溶液由于其特殊性质，如高介电损耗、高分子量和高沸点，可作为微波加热的良好溶剂，并且发现它是比蒸馏水更合适的介质。采用光热电流技术测量了样品的热扩散率。通过将蒸馏水和乙二醇的测量热扩散率与文献报道的值进行比较，确定了该技术的精度和准确性。对于蒸馏水和乙二醇，银纳米流体的热扩散率分别提高到了1.15和1.25。
