Particulate Templates and Ordered Liquid Bridge Networks in Evaporative Lithography

Abstract

We investigate the properties of latex particle templates required to optimize the development of ordered liquid bridge networks in evaporative lithography. These networks are key precursors in the assembly of solutions of conducting nanoparticles into large, optically transparent, and conducting microwire networks on substrates (Vakarelski, I. U.; Chan, D. Y. C.; Nonoguchi, T.; Shinto, H.; Higashitani, K. Phys. Rev. Lett., 2009, 102, 058303). An appropriate combination of heat treatment and oxygen plasma etching of a close-packed latex particle monolayer is shown to create open-spaced particle templates which facilitates the formation of ordered fully connected liquid bridge networks that are critical to the formation of ordered microwire networks. Similar results can also be achieved if non-close-packed latex particle templates with square or honeycomb geometries are used. The present results have important implications for the development of the particulate templates to control the morphology of functional microwire networks by evaporative lithography.

Hierarchical Assembly of Plasmonic Nanoparticles*

“…Vakarelski et al demonstrated formation of gold wires in am acroscale connected network using ac olloidal mask of latex beads. [36][37]45] Importantly,t he addition of surfactant was important to stabilize the liquid film and allow the formation of the plasmonic network upon drying (Figure 4A,B). In order to improvet he reproducibility and versatility,t he authors used ap hotoresist as am askt od irect the drying of the goldc olloid ( Figure 4C).…”

Printable Functional Chips Based on Nanoparticle Assembly

“…Vakarelski's group observed the phenomena of different liquid bridge network formations by a gold NP-suspended solution on a latex particle self-assembly as templates. [118,119] Then, an gold NPs aqueous suspension was doped on the template and deposited on the substrate: a connected liquid bridge network formed between the substrate and the latex particles and guided the gold NPs deposited in certain distribution. The effect of surfactants and surface tension displays crucial roles on the stability and formation of the initial liquid bridges.…”

Continuous Microwire Patterns Dominated by Controllable Rupture of Liquid Films

“…0.6–1 wt%, liquid films were inclined to break in the gaps among the micropillars (Figure S1a‐c). Thus, discontinuous liquid bridges have been generated connecting neighboring micropillars (Figure S1e), which have been systematically studied by several reports 8–13. Due to the diverse gap values in horizontal/vertical directions, the as‐prepared microwires preferred to form perpendicularly (The details of vertical microwire formation can be found in the Section One and Figure S2 in Supporting Information).…”

“…Then, order‐packed polystyrene (PS) spheres have been utilized to serve as the wetting defect points for pining the liquids and guiding their rupture 8, 9. The liquid films are inclined to break regularly in the gaps among PS spheres, yielding a variety of fully connected, symmetrical microwire network.…”

“…Besides above topographically introduced breaking behaviors, very recently, we have found the solution concentration will tailor the rupture model of liquid films. In the case of low concentration, the polymeric liquid films will break around the micropillars rather than that in the pillar gaps 8–13. Thus, continuous microwire architectures can be formed instead of discontinuous microwires bridging neighboring micropillars.…”