Figure 9.

Fabrication process of metamaterial based microfluidic chemical sensor developed on paper substrate: (a) wax printer used for wax-printing on chromatography paper; (b) polyimide Sheet cut by CO₂ laser used as interface layer on wax printed paper; (c) painting silver ink; (d) peeling polyimide sheet off the paper; (e) silver-painted paper after peeling off polyimide sheet; (f) flow of water through the microfluidic channels; (g) unit cell of the proposed sensor, the thickness of the chromatography paper and conductive silver disks are 90 μm and 100 μm, respectively; (h) fabricated sample (dimensions of 11.5 × 11.5 cm²), inhomogeneity of the silver disks due to low resolution in painting are shown on the inset figure; (i) flow of dye on microfluidic channel; and (j) channels are filled with dye, and the source of the dye is also shown (redrawn from [3]).