Fabrication of robust, high-quality two-dimensional colloidal crystals from aqueous suspensions containing water-soluble polymer

In this letter, we report that two-dimensional (2D) polystyrene colloidal crystals of much higher quality can be fabricated in a single-step confined convective assembly process by introducing water-soluble polymer into the colloidal suspension. The presence of the water-soluble polymer in the aqueous phase enables the colloidal particles to arrange into more hexagonally close-packed single crystalline domains, and thus reduces the defect density. In addition, the physical stability of the final 2D colloidal crystals is improved because each particle is bonded to neighboring particles and to the substrate by polymer bridges. (c) 2006 American Institute of Physics.