Reversible Size Control of Liquid-Metal Nanoparticles under Ultrasonication.
This paper describes the reversible control of the size of liquid-metal nanoparticles under ultrasonication. Gallium was utilized as a liquid metal, which has a melting point of 29.8 °C. Investigating the effects of ultrasonication (power, time, and temperature) on the formation of gallium nanoparticles revealed that the process is similar to the formation of oil in water (O/W) or water in oil (W/O) emulsions, as the temperature significantly affects the size of the gallium nanoparticles (GaNPs). Under ultrasonication, the balance between the break-up and coalescence of the GaNPs can be adjusted by changing the temperature or adding acid through modulating the natural surface oxide layer (which can be removed with acid) and the stabilizing effect of the surfactant dodecanethiol. Coalescence was predominant at higher temperatures, whereas particle break-up was found to be predominant at lower temperatures. Furthermore, the change in size was accompanied by a shift in the plasmonic absorption of the GaNPs in the UV region.
Iyoda Supra-integrated Material Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan). yamaguchi.a.af@m.titech.ac.jp.
Akihisa
A
Yamaguchi
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-Cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan).
Yu
Y
Mashima
Iyoda Supra-integrated Material Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan).
Tomokazu
T
Iyoda
gallium; liquid metals; nanoparticles; surface plasmon resonance; ultrasonication