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Influence of Water on the Interfacial Behavior of Gallium Liquid Metal Alloys
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posted on 2014-12-24, 00:00 authored by Mohammad
R. Khan, Chris Trlica, Ju-Hee So, Michael Valeri, Michael D. DickeyEutectic
gallium indium (EGaIn) is a promising liquid metal for
a variety of electrical and optical applications that take advantage
of its soft and fluid properties. The presence of a rapidly forming
oxide skin on the surface of the metal causes it to stick to many
surfaces, which limits the ability to easily reconfigure its shape
on demand. This paper shows that water can provide an interfacial
slip layer between EGaIn and other surfaces, which allows the metal
to flow smoothly through capillaries and across surfaces without sticking.
Rheological and surface characterization shows that the presence of
water also changes the chemical composition of the oxide skin and
weakens its mechanical strength, although not enough to allow the
metal to flow freely in microchannels without the slip layer. The
slip layer provides new opportunities to control and actuate liquid
metal plugs in microchannelsincluding the use of continuous
electrowettingenabling new possibilities for shape reconfigurable
electronics, sensors, actuators, and antennas.