Optimal synthesis and characterization of Ag nanofluids by electrical explosion of wires in liquids
© Ju Park et al; licensee Springer. 2011
Received: 30 October 2010
Accepted: 15 March 2011
Published: 15 March 2011
Silver nanoparticles were produced by electrical explosion of wires in liquids with no additive. In this study, we optimized the fabrication method and examined the effects of manufacturing process parameters. Morphology and size of the Ag nanoparticles were determined using transmission electron microscopy and field-emission scanning electron microscopy. Size and zeta potential were analyzed using dynamic light scattering. A response optimization technique showed that optimal conditions were achieved when capacitance was 30 μF, wire length was 38 mm, liquid volume was 500 mL, and the liquid type was deionized water. The average Ag nanoparticle size in water was 118.9 nm and the zeta potential was -42.5 mV. The critical heat flux of the 0.001-vol.% Ag nanofluid was higher than pure water.
As noble metal materials, silver nanoparticles exhibit significantly distinct physical, chemical, and biological properties. Silver nanoparticles have attracted attention in a wide range of application fields [1–4]. Their unique properties result from particles on the nanoscale that are monodispersed and unagglomerated.
Nanofluids, dispersed nanoscale particles suspended in a base fluid , have drawn tremendous interest from scientific and industrial communities because of their unique properties. They have been used in many industrial applications such as heat transfer, automotive, electronic, biomedical device manufacturing, and others [6–10]. In particular, nanofluids have gained interest as heat transfer fluids. Due to the high thermal conductivity of nanoscale metal particles, metal-nanofluids may significantly enhance thermal transport capabilities. Nanofluids have shown the most promise as coolants because they enhance critical heat flux [CHF] [11–13].
Previous works on electrical explosion of wires
Karioris and Fish 
Au, Ag, Al, Cu, Fe, W, Mo, Ni, Th, U, Pt, Mg, Pb, Sn, Ta
Al, Ni, Au, Pt
Voltage: 0-30 kV
where W is the energy deposited in the wire, v is the voltage, and i(τ) is the time integration.
Parameters that can influence the properties of particles synthesized by EEWL include electrical circuit parameters (voltage, capacitance, inductance); the amount of energy deposited in the wire; the properties of the exploding wire (diameter, length, defects); sublimation of the metal; and properties of the liquid (viscosity, thermal conductivity, breakdown strength).
In this study, we produced and characterized pure Ag nanofluids by EEWL. We examined the energy deposition in the wire under various conditions and focused on controlled particle size and stability. To identify the effects of key parameters in EEWL, we designed the experiments using Minitab and observed the Ag particle size, morphology, and dispersibility in nanofluids. For applications such as cooling system for electronics and nuclear reactors, it is important to increase the CHF. Thus, to determine potential for increased CHF, we used the pool boiling test of the Ag nanofluids. Finally, to decrease the particle size and improve the dispersibility of Ag nanofluids, we optimized the processing parameters for EEWL using a response optimization technique [ROT].
The Ag wire (0.1 mm in diameter) was installed in the cylinder filled with the liquids. The capacitor was charged to 3 kV and the current flowed through the wire when the spark-gap switch was closed. High-temperature plasma was generated by the electrical energy deposited in the wire and was condensed by the basic fluids. A self-integrated Rogowsky coil and a high-voltage probe were used to measure the current and voltage waveforms, respectively.
Summary of experimental parameters
7.5 μF, 30 μF
2.8 mm, 3.8 mm
Deionized water, Ethanol
500 mL, 1,000 mL
We analyzed the effects of the energy deposited in the exploding wire on the size and shape of the Ag nanoparticles. The morphology was observed by high-resolution transmission electron microscopy [TEM]. The size and zeta potential of the nanoparticles were measured using a submicron size and zeta potential measuring system (Nano ZS, Malvern, Worcestershire WR14 1XZUK, UK). Adsorption spectra were analyzed using UV/Vis spectroscopy. Design of experiments [DOE] was performed to optimize the control factors for EEWL.
Manufacturing of Ag nanofluids
Average particle size and zeta potential of Ag nanofluids produced by EEWL in deionized water
Average particle size (nm)
Zeta potential (mV)
Figure 6b shows the coagulation of Ag nanoparticles, which was likely a result of three potential processes. First, agglomeration may have occurred during handling or processing due to the high specific surface area of the nanoparticles. Second, it may have occurred during the drying process of sample preparation. Finally, it may have occurred during condensation.
Average particle size and zeta potential of Ag nanofluids
Average particle size (nm)
Zeta potential (mV)
Liquid volume (mL)
In this study, we produced Ag nanofluids by electrical explosion of wires in liquids. By optimizing control parameters, we decreased the particle size under fast explosion conditions and long plasma duration with low-viscosity media. Low viscosity decreased the particle size and dispersion stability due to greater expansion in the plasma volume. The process was optimized by ROT when capacitance was 30 μF, wire length was 38 mm, liquid volume was 500 mL, and the liquid type was deionized water. For the repeated experiment, the average particle size of the Ag nanoparticles in water was 118.9 nm and the zeta potential was -42.5 mV. The CHF of the 0.001-vol.% Ag nanofluid was higher than that of pure water.
This research was partly supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010-0023511) and the Fostering of Regional Strategic Industry Program though the Ministry of Knowledge Economy (70007094).
- Karpinski AP, Russell SJ, Serenyi JR, Murphy JP: Silver based batteries for high power applications. Journal of Power Sources 2000, 91: 77–82. 10.1016/S0378-7753(00)00489-4View Article
- Liu C, Yang X, Yuan H, Zhou Z, Xiao D: Preparation of Silver Nanoparticle and Its Application to the Determination of ct-DNA. Sensors 2007, 7: 708–718. 10.3390/s7050708View Article
- Tolaymat TM, El Badawy AM, Genaidy A, Scheckel KG, Luxton TP, Suidan M: An evidence-based environmental perspective of manufactured silver nanoparticle in syntheses and applications: A systematic review and critical appraisal of peer-reviewed scientific papers. Science of The Total Environment 2010, 408: 999–1006. 10.1016/j.scitotenv.2009.11.003View Article
- Cameron DS: Chemistry, Electrochemistry, and Electrochemical Applications Silver. In Encyclopedia of Electrochemical Power Sources. Edited by: ürgen G. Amsterdam: Elsevier; 2009:876–882. full_textView Article
- Cheng P, Choi S, Jaluria Y, Li D, Norris P, Tzou RDY: Special Issue on Micro/Nanoscale Heat Transfer---Part I. Journal of Heat Transfer 2009, 131: 030301. 10.1115/1.3056579View Article
- Siwach OP, Sen P: Fluorescence properties of Fe nanoparticles prepared by electro-explosion of wires. Materials Science and Engineering: B 2008, 149: 99–104. 10.1016/j.mseb.2007.12.007View Article
- Xuan Y, Li Q: Investigation on Convective Heat Transfer and Flow Features of Nanofluids. Journal of Heat Transfer 2003, 125: 151–155. 10.1115/1.1532008View Article
- Patel HE, Das SK, Sundararajan T, Nair AS, George B, Pradeep T: Thermal conductivities of naked and monolayer protected metal nanoparticle based nanofluids: Manifestation of anomalous enhancement and chemical effects. Applied Physics Letters 2003, 83: 2931–2933. 10.1063/1.1602578View Article
- Wong KV, De Leon O: Applications of Nanofluids: Current and Future. Advances in Mechanical Engineering 2010, 2010: 1–12.
- Park H, Liang S: Force modeling of microscale grinding process incorporating thermal effects. The International Journal of Advanced Manufacturing Technology 2009, 44: 476–486. 10.1007/s00170-008-1852-3View Article
- Wang XQ, Mujumdar AS: Heat transfer characteristics of nanofluids: a review. International Journal of Thermal Sciences 2007, 46: 1–19. 10.1016/j.ijthermalsci.2006.06.010View Article
- Cheng L, Mewes D, Luke A: Boiling phenomena with surfactants and polymeric additives: A state-of-the-art review. International Journal of Heat and Mass Transfer 2007, 50: 2744–2771. 10.1016/j.ijheatmasstransfer.2006.11.016View Article
- Yoo DH, Hong KS, Yang HS: Study of thermal conductivity of nanofluids for the application of heat transfer fluids. Thermochimica Acta 2007, 455: 66–69. 10.1016/j.tca.2006.12.006View Article
- Zhou DW: Heat transfer enhancement of copper nanofluid with acoustic cavitation. International Journal of Heat and Mass Transfer 2004, 47: 3109–3117. 10.1016/j.ijheatmasstransfer.2004.02.018View Article
- Santra AK, Sen S, Chakraborty N: Study of heat transfer augmentation in a differentially heated square cavity using copper-water nanofluid. International Journal of Thermal Sciences 2008, 47: 1113–1122. 10.1016/j.ijthermalsci.2007.10.005View Article
- Eastman JA, Choi SUS, Li S, Yu W, Thompson LJ: Anomalously increased effective thermal conductivities of ethylene glycol-based nanofluids containing copper nanoparticles. Applied Physics Letters 2001, 78: 718–720. 10.1063/1.1341218View Article
- Kwon YS, An VV, Ilyin AP, Tikhonov DV: Properties of powders produced by electrical explosions of copper-nickel alloy wires. Materials Letters 2007, 61: 3247–3250. 10.1016/j.matlet.2006.11.047View Article
- Henglein A: Physicochemical properties of small metal particles in solution: "microelectrode" reactions, chemisorption, composite metal particles, and the atom-to-metal transition. The Journal of Physical Chemistry 1993, 97: 5457–5471. 10.1021/j100123a004View Article
- Kim HJ, Bang IC, Onoe J: Characteristic stability of bare Au-water nanofluids fabricated by pulsed laser ablation in liquids. Optics and Lasers in Engineering 2009, 47: 532–538. 10.1016/j.optlaseng.2008.10.011View Article
- Karioris FG, Fish BR: An exploding wire aerosol generator. Journal of Colloid Science 1962, 17: 155–161. 10.1016/0095-8522(62)90006-5View Article
- Couchman JC: Study of the use of cascade impactors for analyzing airborne particles of high specific gravity. In Ph.D thesis. Texas Christian University; 1965.
- Phalen RF: Evaluation of an exploded-wire aerosol generator for use in inhalation studies. Journal of Aerosol Science 1972, 3: 395–400. IN395-IN396, 401–406 IN395-IN396, 401-406 10.1016/0021-8502(72)90094-8View Article
- Cho CH, Park SH, Choi YW, Kim BG: Production of nanopowders by wire explosion in liquid media. Surface and Coatings Technology 2007, 201: 4847–4849. 10.1016/j.surfcoat.2006.07.032View Article
- Park EJ, Bac LH, Kim JS, Kwon YS, Kim JC, Choi HS, Chung YH: Production and Properties of Ag Metallic Nanoparticle Fluid by Electrical Explosion of Wire in Liquid. Journal of Korean Powder Metallurgy Institute 2009, 16: 217–222. 10.4150/KPMI.2009.16.3.217View Article
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.