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Vortex creates nanowires
21 December 2006
Chinese scientists have used miniature whirlpools to grow nanoscale disks and wires.
A team from Anhui Normal University, Wuhu, China, and Wannan Medical College, Wuhu, China, used ethanol flowing round a cylinder to deposit an intricate pattern of tin catalyst. This template could then be used to grow a pattern of silicon disks six micrometres across, connected by fine wires.
The particular pattern used is a line of vortices, which forms in the wake of the cylinder, known as a Karman vortex street. 'The same flow pattern exists in a variety of situations, ranging from flow around the strings of an Aeolian harp to clouds swirling past an island,' said Mingwang Shao, who led the research.
A whirlpool pattern known as Karman vortex street was used as a template to fabricate silicon nanomaterials
'This is an excellent example of the way that conventional physical and chemical phenomena we know well in nature could be utilized by chemists and material scientists for material fabrication,' said Shu-Hong Yu, an expert in nanomaterials and chemistry at the University of Science and Technology of China in Hefei.
The team hopes to use other fluid flow patterns to make 'more special nanomaterials with uncommon structures', said Shao.
Karman vortex street assisted patterning in the growth of silicon nanowires
M Shao, H Hu, M Li, H Ban, M Wang and J Jiang, Chem. Commun., 2007