Nanoparticle-Mediated Assembly of Colloidal Crystals on Patterned Substrates

摘要

Through fundamental studies of the phase behavior and structure of binary mixtures of attractive colloidal microspheres and highly charged nanoparticles, we have discovered a new colloidal stabilization mechanism known as nanoparticle haloing. Colloidal microspheres were assembled onto (100) fcc patterned and non-patterned glass substrates from binary mixtures of varying nanoparticle concentration. Confocal images of such assemblies were acquired in both the wet and dry states, and the position of the particle centers, g(r), and local and global order parameters were obtained through image analysis. Through nanoparticle engineering, we have created robust colloidal crystals that can be harvested from solution without the introduction of drying related defects. Currently, we are developing an optimized drying process that can be used to regulate the point defect distribution within such assemblies.