After plasma surface treatment, Ag nanoparticle ink (NPS-J, Harima
Chemical Co., Japan), which contains 57.3 wt% Ag nanoparticles in
tetradecanewith average particle sizes smaller than 10 nm,was printed
onto the surface-treated substrates to fabricate a 10 × 10 dot array pattern
with a 200 μm dot spacing at three different positions on the substrate.
The ink was ejected from a single piezoelectric printhead with a
30 μm nozzle diameter (MicroFab Co.) installed in an in-house inkjet
printing system. After drying the inkjet-printed patterns, five dots
were randomly chosen from each array, and their diameters weremeasured
using an opticalmicroscope. The average diameter of a total of 15
dots was used to evaluate surface wettability of each surface-treated
substrate.