title: Surface patterning of nanoparticles with polymer patches.
abstract: Patterning of colloidal particles with chemically or topographically distinct surface domains (patches) has attracted intense research interest. Surface-patterned particles act as colloidal analogues of atoms and molecules, serve as model systems in studies of phase transitions in liquid systems, behave as 'colloidal surfactants' and function as templates for the synthesis of hybrid particles. The generation of micrometre- and submicrometre-sized patchy colloids is now efficient, but surface patterning of inorganic colloidal nanoparticles with dimensions of the order of tens of nanometres is uncommon. Such nanoparticles exhibit size- and shape-dependent optical, electronic and magnetic properties, and their assemblies show new collective properties. At present, nanoparticle patterning is limited to the generation of two-patch nanoparticles, and nanoparticles with surface ripples or a 'raspberry' surface morphology. Here we demonstrate nanoparticle surface patterning, which utilizes thermodynamically driven segregation of polymer ligands from a uniform polymer brush into surface-pinned micelles following a change in solvent quality. Patch formation is reversible but can be permanently preserved using a photocrosslinking step. The methodology offers the ability to control the dimensions of patches, their spatial distribution and the number of patches per nanoparticle, in agreement with a theoretical model. The versatility of the strategy is demonstrated by patterning nanoparticles with different dimensions, shapes and compositions, tethered with various types of polymers and subjected to different external stimuli. These patchy nanocolloids have potential applications in fundamental research, the self-assembly of nanomaterials, diagnostics, sensing and colloidal stabilization.
authors.affiliation: Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Rachelle M
authors.initials: RM
authors.lastname: Choueiri
authors.affiliation: Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Galati
authors.affiliation: Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Héloïse
authors.initials: H
authors.lastname: Thérien-Aubin
authors.affiliation: Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Anna
authors.initials: A
authors.lastname: Klinkova
authors.affiliation: Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Egor M
authors.initials: EM
authors.lastname: Larin
authors.affiliation: Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Ana
authors.initials: A
authors.lastname: Querejeta-Fernández
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.|Institute of New Energy Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Han
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Huolin L
authors.initials: HL
authors.lastname: Xin
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Oleg
authors.initials: O
authors.lastname: Gang
authors.affiliation: Institute of Macromolecular Compounds of the Russian Academy of Sciences, Saint Petersburg, 199004, Russia.|Saint Petersburg National University of Informational Technologies, Mechanics and Optics, Saint Petersburg, 197101, Russia.
authors.forename: Ekaterina B
authors.initials: EB
authors.lastname: Zhulina
authors.affiliation: Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Rubinstein
authors.affiliation: Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.|Institute of Biomaterials and Biomedical Engineering, University of Toronto, 4 Taddle Creek Road, Toronto, Ontario M5S 3G9, Canada.|Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Kumacheva