Fig. 2: Aerosol jet printing interdigital transducers (IDTs) with different electrode widths and materials for SAW microfluidics.

a Schematic of the aerosol jet printing process for manufacturing IDTs. The selected electrode material suspension (i.e., ink) is aerosolized via ultrasonication and concentrated by nitrogen sheath flow to print from the nozzle. b Picture of an aerosol jet-printed silver nanowire SAW microfluidic device. The scale bar is ~2 mm. c, d Scanning electron microscope images of printed silver nanowire electrodes at increasing magnification. The scale bar for (c) is 50 μm, and that for (d) is 5 μm. e Comparison of actual (data points) and ideal (dotted line) versus designed printed electrode widths averaged across devices. Sample sizes are 3 different devices, except for the 100 μm devices that have 6. Error bars represent the 95% confidence interval for the designed electrode width, and the—symbol represents the mean printed electrode width. f Comparison of two-terminal conductance to material type for fabricated SAW microfluidic devices, including evaporated-gold and aerosol jet printed materials, including silver nanowire, graphene, and PEDOT:PSS. The electrode dimensions are ~13 x 0.4 mm (LxW), and the respective sample sizes are as follows: evaporated gold = 4, silver nanowire = 6, graphene = 3, and PEDOT:PSS = 3. Error bars represent the 95% confidence interval. Note that PEDOT:PSS does not have a bottom error bar because a negative error bar cannot be displayed in a log-axis plot