Conventional, rigid materials remain the key building blocks of most modern electronic devices, but they are limited
in their ability to conform to curvilinear surfaces. It is possible to make electronic components that are flexible and
in some cases stretchable by utilizing thin films, engineered geometries, or inherently soft and stretchable materials
that maintain their function during deformation. Here, we describe the properties and applications of a
micromoldable liquid metal that can form conductive components that are ultra-stretchable, soft, and shape-reconfigurable.
This liquid metal is a gallium-based alloy with low viscosity and high conductivity. The metal
develops spontaneously a thin, passivating oxide layer on the surface that allows the metal to be molded into non-spherical
shapes, including films and wires, and patterned by direct-write techniques or microfluidic injection.
Furthermore, unlike mercury, the liquid metal has low toxicity and negligible vapor pressure. This paper discusses
the mechanical and electrical properties of the metal in the context of electronics, and discusses how the properties
of the oxide layer have been exploited for new patterning techniques that enable soft, stretchable and reconfigurable
devices.
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