## 2 Experimental Details
### Inkjet Printing  
The ink used in this study is a colloidal suspension containing 56 wt % Ag nanoparticles in tetradecane solvent (NPS-J C-type, Harima Chemicals, Inc., Tokyo, Japan). The diameter of the Ag nanoparticles ranges from 3 nm to 7 nm. The electrical resistivity of the ink is 4.7 \(\upmu\Omega\)-cm, and the viscosity is evaluated as a function of temperature using a cone-plate viscometer (DV-II + Pro with CPE-40 spindle, Brookfield Engineering Laboratories, Inc., Middleboro, MA, USA). Printing experiments are performed in the system consisting of a 2D traverse, an in-house inkjet printer and a piezoelectric single-nozzle printhead with a 30 \(\upmu\)m orifice diameter (MJ-AT-01, MicroFab Technologies, Inc., Plano, TX, USA). The traverse carries substrates along \(x\)- and \(y\)-direction at the various printing speeds determined by printing frequency. The nozzle discharges a flying ink droplet of \(\sim\)30 \(\upmu\)m diameter. Inkjet nanosilver lines with 10 mm length are produced by 200 Hz printing frequency at room temperature throughout all the substrates from \(S\) 30 to \(S\) 90, for the investigation about the dependence of the lines pattern on substrate surface energy. For other investigations in  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Surface** & **Gas** & **RF Power (W)** & **Pressure (Pa)** & **Diameter (\(\upmu\)m)** \\ \hline \(S\) 30 & & 135 & 53.3 & 35 \\ \(S\) 50 & C\({}_{4}\)F\({}_{8}\) & 60 & 26.7 & 54 \\ \(S\) 70\({}^{1}\) & & 165 & 32 & 73 \\ \hline \(S\) 70\({}^{2}\) & C\({}_{4}\)F\({}_{8}\) & 135 & 53.3 & 76 \\  & O\({}_{2 this study, the \(S\) 50 is chosen as a test substrate. The reason of choosing the \(S\) 50 is because it is expected to form inkjet-printed lines with narrower width stably due to the substrate characteristic. The printing frequency is changed from 50 to 1000 Hz and the substrate temperature is adjusted from room temperature to 125 \({}^{\circ}\)C, in order to control the time interval between successive droplet arrivals and the evaporation rate of ink solvent respectively.  
In inkjet printing, the thickness and the width of printed lines generally depend on the spacing between droplets deposited on a substrate, which determines the overlapping degree of the droplets. The droplet overlap is defined by droplet diameter (\(D\)) and droplet-to-droplet distance (\(d\)), as depicted in Figure 1a. As the droplet overlap increases, the spacing between adjoining droplets decreases, indicating that the number of droplets in unit length increases. On \(S\) 30 to \(S\) 90 substrates, inkjet nanosilver lines are fabricated with three droplet overlaps: 20%, 40% and 60%.  
Droplet deposition procedures also give a major effect on the formation of continuous lines, as shown in Figure 1b. In continuous printing procedure, inkjet lines are produced by arranging ink droplets at smaller interval (\(d\)) than their diameter (\(D\)) in linear single-pass deposition. Otherwise, they break up into individual isolated droplets. In interlacing printing procedure, ink droplets are deposited in larger interval than \(D\) at first pass and then, their gaps are filled up by the droplets deposited at second pass for the formation of continuous inkjet lines. This mode requires the droplet spacing at first pass that is two times larger than the continuous printing mode, in order to print the inkjet lines with same resolution.  
The increase of thickness of inkjet-printed features needs to overprint ink droplets onto as-printed layers. In this study, the total four overprinting are performed and at every overprinting, ink droplets are deposited after the complete drying of as-printed layers.  
Figure 1: Schematic diagrams of (**a**) droplet overlap as the ratio between neighboring droplets and (**b**) different modes of a printing procedure to form a continuous line.