Stretchable Electronics For Wearables, Soft Robotics

Soft robotics, wearable technologies, and biomedical applications all require stretchable electronics. However, the current methods of production have limited their potential. A group of researchers has created a material and fabrication process that can quickly make these devices stretchier, more durable, and ready for mass production.

One of the most difficult challenges for stretchable electronics is connecting stretchable conductors to the rigid materials used in commercially available electronics components like resistors, capacitors, and light-emitting diodes (LEDs). When stretchable materials bend and elongate, a large shear force develops at the interface, ripping apart the connection and rendering the circuit inoperable.

The researchers created a new biphasic Ga-In (bGaIn) with both solid and liquid elements using eGaIn nanoparticles. When heated to 900 degrees Celsius, an eGaIn nanoparticle film changes shape, forming a thin, solid oxide layer on top of a thick layer of solid particles embedded in liquid eGaIn. When the material is peeled off, it is transferred to stretchable substrates, similar to how temporary tattoos work.

Although eutectic gallium-indium (eGaIn), which remains liquid at room temperature, has been used for connections in stretchable electronics, its high surface tension prevents it from properly connecting to rigid components. Various strategies have been employed to get around this problem but at the expense of limiting the stretchability and durability of the resulting circuits.

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