Guided assembly by surface controlled dewetting and evapora

Dewetting and evaporation are ubiquitous phenomena that are affected by surface properties. Here we introduce the use of microfabricated surface relief features to control the two processes for the generation of various micro/nanostructures. When dewetting is performed on microwells, long DNA molecules are stretched, aligned, and immobilized into a large-area, highly ordered array. Simulation of the dewetting process reveals the micrometer-scale flow patterns and provides insight for understanding the phenomenon. When an array of micropillars is dewetted by a solution of DNA or polymer, long, continuous nanowires are generated. The nanowires can be easily functionalized through the incorporation of various molecules or nanoparticles. When a solution of concentrated salt or small molecules is used, micro/nanoparticles are formed on top of the micropillars as a result of discontinuous dewetting and droplet evaporation. In addition, this method can produce a hybrid array containing both particles and nanowires in a single step by simply including the building block materials in the dewetting solution. This approach is simple, inexpensive, reliable, and versatile, and therefore holds potential for various applications.