Learning From "Coffee Rings": Ordered Structures Crafted by Controlled Evaporative Self‐Assembly and Flow‐Enabled Self‐Assembly
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Self-assembly of micro- and nano-scale materials to form well-ordered structures promises new opportunities for developing miniaturized electronic, optoelectronic, and magnetic devices. In this regard, several elegant methods based upon self-assembly have emerged, for example, self-directed self-assembly and electrostatic self-assembly. Dynamic self-assembly of nonvolatile solutes via irreversible solvent evaporation has been recognized as an extremely simJ route to intriguing structures. However, these dissipative structures are often randomly organized this presentation, I will show two simple yet robust techniques based on very familiar "coffee ring'' phenomena to produce a large variety of intriguing structures (e.g., concentric rings, fingers, spo~ squares, triangular contour lines, ellipses, etc.) consisting of polymers or nanocrystals (NCs) with unprecedented regularity by allowing a drop of polymer or NC solution to evaporate in curve-on-fl geometries and two-parallel-plate geometry, respectively. These techniques, which dispense with need for lithography and external fields, are fast and cost-effective. As such, they represent powe strategies for creating highly structured, multifunctional materials and devices.
- Nano@Tech Lecture Series