title: Self-assembly of doublets from flattened polymer colloids.
abstract: Bottom-up fabrication methods are used to assemble strong yet flexible colloidal doublets. Part of a spherical particle is flattened, increasing the effective interaction area with another particle having a flat region. In the presence of a moderate ionic strength, the flat region on one particle will preferentially "bond" to a flat region on another particle in a deep (≥10 kT) secondary energy minimum. No external field is applied during the assembly process. Under the right conditions, the flat-flat bonding strength is ≥10× that of a sphere-sphere interaction. Not only can flat-flat bonds be quite strong, but they are expected to remain freely rotatable and flexible, with negligible energy barriers for rotation because particles reside in a deep secondary energy minimum with a ~20-30 nm layer of fluid between the ~1 μm radius particles. We present a controlled technique to flatten the particles at room temperature, the modeling of the interparticle forces for flattened spheres, and the experimental data for the self-assembly of flat-flat doublets.
authors.affiliation: Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
authors.forename: Laura Mely
authors.initials: LM
authors.lastname: Ramírez
authors.forename: Adrian S
authors.initials: AS
authors.lastname: Smith
authors.forename: Deniz B
authors.initials: DB
authors.lastname: Unal
authors.forename: Ralph H
authors.initials: RH
authors.lastname: Colby
authors.forename: Darrell
authors.initials: D
authors.lastname: Velegol