Soft-matter electronics with stencil lithography

We present a mask deposition technique used to create a capacitive soft-matter sensing skin. The device comprises a 6 × 6 grid of liquid Gallium-Indium alloy parallel-plate capacitors embedded in elastomer. Pressing or stretching the skin results in a measurable increase in capacitance at the affected grid points, allowing for real-time monitoring. Printer paper resists liquid metal wetting and is used as a mask during fabrication. Liquid metal is applied across the mask with an elastomer-tipped pen, selectively wetting to the elastomer substrate. With laser-cut printer paper, features as small as 250 μm are demonstrated.