After nearly three decades of effort, it is now possible to synthesize nanostructured materials of well-controlled composition, size, surface functionalization, and physical properties. The next phase of nanotechnology development is the controlled assembly of nanoscale building blocks into desired superstructures up to bulk dimensions and their precise positioning at the desired locations, which however remain key challenges due to the lack of effective tools and mechanisms. In this presentation, we report our recent progress in this direction. We first describe the self-assembly of uniform superstructures at all scales using an emulsion-based template-assisted self-assembly strategy. This new strategy is designed by taking advantage of the partial miscibility of a solvent mixture, which makes it possible to generate transient emulsion droplets containing the target building blocks and carry them into templating holes patterned on a substrate, producing well-defined superstructures with the positional order defined by the template. This strategy is simple, low-cost, high-throughput, and scalable, and it demonstrates high controllability and general applicability in producing superstructures. Secondly, we report an Electric Field-Assisted Surface-Sorption nano-Printing (EFASP) method to allow fast, nanometer-precision printing of nanoparticles over large areas with high reproducibility. As an additive nanofabrication method, it utilizes a tip-based high-voltage writing process to generate nanoscale de-fluorinated patterns in a fluorinated surface, which not only enables electrostatic trapping but also creates a high local surface potential in contrast to the fluorinated area. As a result, the method combines dielectrophoretic enrichment and deep surface-energy modulation, featuring high efficiency and extraordinary robustness of nanoparticle printing. The method also supports the combinatorial pattern of multiple functional nanoparticles for realizing multi-color printing, by conveniently repeating the writing and assembly cycles.

All-scale assembly and precise positioning of colloidal superstructures

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.