title: Synthesis of mono-dispersed nanofluids using solution plasma.
abstract: Small-sized and well-dispersed gold nanoparticles (NPs) for nanofluidics have been synthesized by electrical discharge in liquid environment using termed solution plasma processing (SPP). Electrons and the hydrogen radicals are reducing the gold ions to the neutral form in plasma gas phase and liquid phase, respectively. The gold NPs have the smallest diameter of 4.9 nm when the solution temperature was kept at 20 °C. Nucleation and growth theory describe the evolution of the NP diameter right after the reduction reaction in function of the system temperature, NP surface energy, dispersion energy barrier, and nucleation rate. Negative charges on the NPs surface during and after SPP generate repulsive forces among the NPs avoiding their agglomeration in solution. Increasing the average energy in the SPP determines a decrease of the zeta potential and an increase of the NPs diameter. An important enhancement of the thermal conductivity of 9.4% was measured for the synthesized nanofluids containing NPs with the smallest size.
authors.affiliation: Graduate School of Materials Engineering, Nagoya University , Furo-cho, Chikusa-ku, Nagoya, Japan.
authors.forename: Yong Kang
authors.identifier: 0000-0002-4363-0462
authors.initials: YK
authors.lastname: Heo
authors.forename: Maria Antoaneta
authors.initials: MA
authors.lastname: Bratescu
authors.forename: Tomonaga
authors.initials: T
authors.lastname: Ueno
authors.forename: Nagahiro
authors.initials: N
authors.lastname: Saito
references.citation: J Colloid Interface Sci. 2008 Jan 15;317(2):351-74
references.pmid: 18028940
references.citation: Nat Chem. 2010 Apr;2(4):274-9
references.pmid: 21124507