Tseng Kuo-Hsiung, Lin Yur-Shan, Lin Yun-Chung, Tien Der-Chi, Stobinski Leszek
Department of Electrical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan.
Power Department, Quanta Computer lnc., Taipei 111, Taiwan.
Nanomaterials (Basel). 2020 Jun 1;10(6):1091. doi: 10.3390/nano10061091.
Using the electrical spark discharge method, this study prepared a nano-Ag colloid using self-developed, microelectrical discharge machining equipment. Requiring no additional surfactant, the approach in question can be used at the ambient temperature and pressure. Moreover, this novel physical method of preparation produced no chemical pollution. This study conducted an in-depth investigation to establish the following electrical discharge conditions: gap electrical discharge, short circuits, and open circuits. Short circuits affect system lifespan and cause electrode consumption, resulting in large, non-nanoscale particles. Accordingly, in this study, research for and design of a new logic judgment circuit set was used to determine the short-circuit rate. The Ziegler-Nichols proportional-integral-derivative (PID) method was then adopted to find optimal PID values for reducing the ratio between short-circuit and discharge rates of the system. The particle size, zeta potential, and ultraviolet spectrum of the nano-Ag colloid prepared using the aforementioned method were also analyzed with nanoanalysis equipment. Lastly, the characteristics of nanosized particles were analyzed with a transmission electron microscope. This study found that the lowest ratio between short-circuit rates was obtained (1.77%) when PID parameters were such that K was 0.96, K was 5.760576, and K was 0.039996. For the nano-Ag colloid prepared using the aforementioned PID parameters, the particle size was 3.409 nm, zeta potential was approximately -46.8 mV, absorbance was approximately 0.26, and surface plasmon resonance was 390 nm. Therefore, this study demonstrated that reducing the short-circuit rate can substantially enhance the effectiveness of the preparation and produce an optimal nano-Ag colloid.
本研究采用电火花放电法，利用自行研制的微电火花加工设备制备了纳米银胶体。该方法无需额外的表面活性剂，可在常温常压下使用。此外，这种新颖的物理制备方法不会产生化学污染。本研究进行了深入调查，以确定以下放电条件：间隙放电、短路和开路。短路会影响系统寿命并导致电极消耗，从而产生大的非纳米级颗粒。因此，在本研究中，通过研究和设计新的逻辑判断电路集来确定短路率。然后采用齐格勒-尼科尔斯比例积分微分（PID）方法来寻找最佳PID值，以降低系统的短路率与放电率之比。还使用纳米分析设备分析了用上述方法制备的纳米银胶体的粒径、zeta电位和紫外光谱。最后，用透射电子显微镜分析了纳米颗粒的特性。本研究发现，当PID参数为K为0.96、K为5.760576、K为0.039996时，短路率之比最低（1.77%）。对于用上述PID参数制备的纳米银胶体，粒径为3.409nm，zeta电位约为-46.8mV，吸光度约为0.26，表面等离子体共振为390nm。因此，本研究表明，降低短路率可显著提高制备效果，并产生最佳的纳米银胶体。
