Tseng Kuo-Hsiung, Chung Meng-Yun, Chang Chaur-Yang
Department of Electrical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan.
Nanomaterials (Basel). 2017 Jun 2;7(6):133. doi: 10.3390/nano7060133.
In this study, the Electric Spark Discharge Method (ESDM) was employed with micro-electrical discharge machining (m-EDM) to create an electric arc that melted two electrodes in deionized water (DW) and fabricated nano-Au colloids through pulse discharges with a controlled on-off duration (T-T) and a total fabrication time of 1 min. A total of six on-off settings were tested under normal experimental conditions and without the addition of any chemical substances. Ultraviolet-visible spectroscopy (UV-Vis), Zetasizer Nano measurements, and scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analyses suggested that the nano-Au colloid fabricated at 10-10 µs (10 µs on, 10 µs off) had higher concentration and suspension stability than products made at other T-T settings. The surface plasmon resonance (SPR) of the colloid was 549 nm on the first day of fabrication and stabilized at 532 nm on the third day. As the T-T period increased, the absorbance (i.e., concentration) of all nano-Au colloids decreased. Absorbance was highest at 10-10 µs. The SPR peaks stabilized at 532 nm across all T-T periods. The Zeta potential at 10-10 µs was -36.6 mV, indicating that no nano-Au agglomeration occurred and that the particles had high suspension stability.
在本研究中，采用电火花放电法（ESDM）结合微电火花加工（m-EDM）在去离子水（DW）中产生电弧，使两个电极熔化，并通过具有可控通断持续时间（T-T）和总制备时间为1分钟的脉冲放电制备纳米金胶体。在正常实验条件下且不添加任何化学物质的情况下，共测试了六种通断设置。紫外可见光谱（UV-Vis）、纳米粒度分析仪测量以及扫描电子显微镜-能量色散X射线（SEM-EDX）分析表明，在10-10微秒（10微秒导通，10微秒关断）制备的纳米金胶体比在其他T-T设置下制备的产品具有更高的浓度和悬浮稳定性。胶体的表面等离子体共振（SPR）在制备第一天为549纳米，第三天稳定在532纳米。随着T-T周期增加，所有纳米金胶体的吸光度（即浓度）均下降。在10-10微秒时吸光度最高。在所有T-T周期内，SPR峰均稳定在532纳米。10-10微秒时的zeta电位为-36.6毫伏，表明未发生纳米金团聚，颗粒具有高悬浮稳定性。
