Surface roughness directed self-assembly of patchy particles into colloidal micelles.
Colloidal particles with site-specific directional interactions, so called "patchy particles", are promising candidates for bottom-up assembly routes towards complex structures with rationally designed properties. Here we present an experimental realization of patchy colloidal particles based on material independent depletion interaction and surface roughness. Curved, smooth patches on rough colloids are shown to be exclusively attractive due to their different overlap volumes. We discuss in detail the case of colloids with one patch that serves as a model for molecular surfactants both with respect to their geometry and their interactions. These one-patch particles assemble into clusters that resemble surfactant micelles with the smooth and attractive sides of the colloids located at the interior. We term these clusters "colloidal micelles". Direct Monte Carlo simulations starting from a homogeneous state give rise to cluster size distributions that are in good agreement with those found in experiments. Important differences with surfactant micelles originate from the colloidal character of our model system and are investigated by simulations and addressed theoretically. Our new "patchy" model system opens up the possibility for self-assembly studies into finite-sized superstructures as well as crystals with as of yet inaccessible structures.
Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for NanoMaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. d.j.kraft@uu.nl
Daniela J
DJ
Kraft
Ran
R
Ni
Frank
F
Smallenburg
Michiel
M
Hermes
Kisun
K
Yoon
David A
DA
Weitz
Alfons
A
van Blaaderen
Jan
J
Groenewold
Marjolein
M
Dijkstra
Willem K
WK
Kegel
D000818:Animals; D016880:Anisotropy; D002462:Cell Membrane / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry*; D006801:Humans; D008823:Micelles; D008956:Models, Chemical; D009010:Monte Carlo Method; D011108:Polymers / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D003102:Colloids; D008823:Micelles; D011108:Polymers; D011137:Polystyrenes; D014867:Water