Size reduction of nanoparticle ink patterns by fluid-assisted dewetting

A novel method is proposed to considerably reduce the size of partially wetting patterns of nanopaticle solutions (nanoinks) on a substrate. A nanoink prepared by suspending gold nanoparticles in toluene was deposited on a glass substrate by writing a thin line with the width of 70 mu m. A water droplet of about 100 mu l covering the pattern was employed to shrink the pattern by transport of the toluene from the nanoink to the water region triggered by controlled heat addition from the substrate, which increased the solubility of toluene into water (these two liquids are practically immiscible at room temperature). During the dewetting phase, the three-phase-contact line is pulled by the uncompensated Young's force. The dewetting dynamics is explained by the action of thermocapillarity enhanced by the convection microflow generated in the water layer. (c) 2006 American Institute of Physics.