title: Direct visualization of conformation and dense packing of DNA-based soft colloids.
abstract: Soft colloids--such as polymer-coated particles, star polymers, block-copolymer micelles, microgels--constitute a broad class of materials where microscopic properties such as deformability and penetrability of the particle play a key role in tailoring their macroscopic properties which is of interest in many technological areas. The ability to access these microscopic properties is not yet demonstrated despite its great importance. Here we introduce novel DNA-coated colloids with star-shaped architecture that allows accessing the above local structural information by directly visualizing their intramolecular monomer density profile and arm's free-end locations with confocal fluorescent microscopy. Compression experiments on a two-dimensional hexagonal lattice formed by these macromolecular assemblies reveal an exceptional resistance to mutual interpenetration of their charged corona at pressures approaching the MPa range. Furthermore, we find that this lattice, in a close packing configuration, is surprisingly tolerant to particle size variation. We anticipate that these stimuli-responsive materials could aid to get deeper insight in a wide range of problems in soft matter, including the study and design of biomimetic lubricated surfaces.
authors.affiliation: Forschungszentrum Jülich, Institute of Complex Systems 3, Leo-Brandt-Straße, 52425 Jülich, Germany.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Forschungszentrum Jülich, Institute of Complex Systems 3, Leo-Brandt-Straße, 52425 Jülich, Germany and Department of Physics and Astronomy, Laboratory for Acoustics and Thermal Physics, Katholieke Universiteit Leuven, Celestijnenlaan 200D, Leuven B-3001, Belgium.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Lettinga
authors.affiliation: Forschungszentrum Jülich, Institute of Complex Systems 3, Leo-Brandt-Straße, 52425 Jülich, Germany and Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
authors.forename: Jan K G
authors.initials: JK
authors.lastname: Dhont
authors.affiliation: Forschungszentrum Jülich, Institute of Complex Systems 3, Leo-Brandt-Straße, 52425 Jülich, Germany.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Stiakakis
mesh_terms: D003102:Colloids / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D018613:Microscopy, Confocal / Q000379:methods; D009690:Nucleic Acid Conformation
chemical_list: D003102:Colloids; D004573:Electrolytes; D005456:Fluorescent Dyes; D004247:DNA