Harnessing Colloidal Crack Formation by Flow-Enabled Self-Assembly.

Self-assembly of nanomaterials to yield a wide diversity of high-order structures, materials, and devices promises new opportunities for various technological applications. Herein, we report that crack formation can be effectively harnessed by elaborately restricting the drying of colloidal suspension using a flow-enabled self-assembly (FESA) strategy to yield large-area periodic cracks (i.e., microchannels) with tunable spacing. These uniform microchannels can be utilized as a template to guide the assembly of Au nanoparticles, forming intriguing nanoparticle threads. This strategy is simple and convenient. As such, it opens the possibility for large-scale manufacturing of crack-based or crack-derived assemblies and materials for use in optics, electronics, optoelectronics, photonics, magnetic device, nanotechnology, and biotechnology.