Patterned when Wet: Environment-dependent Multifunctional Patterns in Amphiphilic Colloidal Crystals


Adrian M. Brozell, Michelle A. Muha, Arian Abed-Amoli, Daniel Bricarello and Atul N. Parikh, Nano Letters 7, 3822-3826, 2007

A simple integration of molecular and colloidal self-assembly approaches with photopatterning is shown to produce multifunctional patterns of amphiphilic colloidal crystals. These crystals display binary spatial patterns of wettability by water and a single photonic stop-band in air. Upon exposure to water, the uniform stop-band is replaced by a pattern of coexisting stop-bands that reflect the underlying pattern of surface wetting. These hydration-dependent photonic patterns within single colloidal crystals form because of near-complete water rejection from the three-dimensionally disposed nanoscale interstices in hydrophobic regions and its exclusive permeation within the hydrophilic regions. This water permeation pattern is further structured by the three-dimensional (3D) distribution and contiguity of the nanoscale interstices between individual colloids, allowing 3D patterned organization of functional units in secondary self-assembly processes, as illustrated using quantum dots, metal nanoparticles, and fluorescent probes.