Low-Cost Disposable Microglow Discharge Chip on Paper Substrate for Aqueous Sample Analysis

The work reports the fabrication of a disposable, low-cost, miniaturized microplasma device on a paper substrate utilizing a micropatterned copper ribbon as the metal electrode and a layer of porous silica to introduce the liquid into the glow discharge. The porous layer is made by stamping a film of sol-gel silica, followed by curing. The device has an inter-electrode gap of 65 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \mathrm{m}$</tex> and occupies a total area of only 6.5 mm x 3 mm on a flexible paper substrate. The fabricated device shows the wet plasma glow operated in air ambient at 1 atm. The device has been shown to detect 1 mM of sodium and lithium ions in solution with an intake of 0.4 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \mathrm{L}$</tex> only.