Template-directed assembly on an ordered microsphere array.

We investigated the capability of an ordered array of microspheres to act as a template for deposition and ordering of a subsequent layer of microspheres. An evaporation-based technique was used to deposit monolayers of large colloidal spheres. A novel technique for selective deposition of polyelectrolyte film was used to stabilize the arrays and optimize the bead-substrate interaction. The template behavior of face-centered cubic and body-centered cubic (bcc) microsphere arrays was studied by optical and scanning electron microscopy, and the packing geometry was found to have a dramatic effect on the arrangement of the subsequent layer. A geometrical interpretation of the experimental data explains why a bcc bead array is well suited to act as a template for an additional layer of microspheres.