Observation of long-range orientational order in monolayers of polydisperse colloids.
Polydisperse amorphous-silicon colloidal particles ranging from approximately 10 to 140 nm in diameter were evaporated onto carbon substrates. The particles formed close-packed monolayers in which each particle had 6-fold nearest-neighbor coordination characteristic of a hexagonal lattice yet completely lacked positional order. Orientational correlation functions were calculated for the particles and found to be constant throughout the aggregate, indicating the occurrence of long-range orientational order. Computer simulations revealed that the structural organization in this system resulted from capillary immersion forces that lead to a size separation as the particles deposit from the evaporating solvent onto the substrate.
Rabideau
Brooks D
BD
Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, 1 University Station C0400, The University of Texas, Austin, TX 78712-1062, USA.
Pell
Lindsay E
LE
Bonnecaze
Roger T
RT
Korgel
Brian A
BA