title: Two-dimensional directed assembly of dicolloids.
abstract: The assembly of ordered dicolloid monolayers is directed by an electric field. The dicolloid particles are polystyrene latex with a maximum equatorial diameter 3.45 μm and length 4.63 μm. The monolayer structure is characterized using small-angle light scattering and bright-field microscopy. With increasing field strength from 26.7 to 200 V(RMS)/cm, a transition from a disordered monolayer, to first orientationally ordered, and then translationally ordered two-dimensional (2D) arrays occurs. A c2mm plane group symmetry dominates the ordered structure but is present alongside structures with p2 symmetry, leading to a spread in the angular distribution of the light scattering peaks. The order-disorder transition dependence on field strength and frequency is similar to that observed for colloidal spheres; at higher frequencies, stronger fields are required to assemble particles. Optimal ordered structures reflect a balance between inducing sufficiently strong interparticle interactions while limiting the rate of formation to ensure the growth of large crystalline domains.
authors.affiliation: Department of Chemical and Biomolecular Engineering and Center for Molecular and Engineering Thermodynamics, Allan P. Colburn Laboratory, 150 Academy Street, University of Delaware, Newark, Delaware 19716, United States.
authors.forename: Mark M
authors.initials: MM
authors.lastname: Panczyk
authors.forename: Jin-Gyu
authors.initials: JG
authors.lastname: Park
authors.forename: Norman J
authors.initials: NJ
authors.lastname: Wagner
authors.forename: Eric M
authors.initials: EM
authors.lastname: Furst