Microscopic Composition Maps of Poly(styrene-co-2-hydroxyethyl methacrylate) Colloidal Crystals and Interconnected Colloidal Arrays

Colloidal crystalline films were prepared from poly(styrene-co-2-hydroxyethyl methacrylate) (PS−HEMA) latex particles by evaporative deposition. The hexagonally ordered surfaces of the colloidal crystals (CCs) were transformed with styrene vapor at room temperature to interconnected colloidal arrays (ICAs) that have a honeycomb-like ridge of polymer surrounding hexagonally ordered dimples in the surface. When the styrene vapor temperatures were increased systematically to 45 °C, the regularity of ICA structure decreased and finally disappeared. Images from transmission electron microscopy (TEM) and from atomic force microscopy (AFM) show that the surfaces of the PS−HEMA particles and the ICAs have raspberry textures. Monolayer CCs and ICAs fabricated on TEM grids were analyzed by energy dispersive spectroscopy (EDS) to determine the elemental compositions of the different regions of the textured surfaces. Carbon, oxygen, and sulfur were distributed all over the surface of the CC. While carbon was distribu...