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Nanoparticles in a Perpetual Solid–Liquid State

Imagine placing ice cubes into a glass of water and having the ice cubes remain unchanged and in the same state for hours, even under intense heat or freezing conditions. An international research team has made a similar discovery using gallium nanoparticles.

The researchers used advanced electron microscopy facilities at The University of Western Australia and imaged the atomic arrangement within gallium nanoparticles. Gallium is a soft, silvery-blue metal at room temperature that melts at 30°C. At a temperature below –18°C it becomes hard and brittle.

“We discovered that, by controlling the growth of the nanoparticles on the substrate, both a liquid and solid state are possible in the metal nanoparticle at a same time,” said Dr Alexandra Suvorova of The University of Western Australia’s Centre for Microscopy, Characterisation and Analysis. “The finding was surprising, especially because of its stability over such a large temperature range.”

Suvorova said the discovery was a major breakthrough in understanding the nanoscale behaviour of gallium, and created new possibilities for its future development and use. “Gallium is an important element in electronics and is used in microwave circuits, high-speed switching circuits and infrared circuits,” she said.

“The discovery of this new part-solid, part-liquid nanoparticle phase could be useful in ultraviolet sensors, molecular sensing devices and enhanced photodetectors.”

The research been published in Nature Materials.