title: Using light to covalently immobilize and pattern nanoparticles onto surfaces.
abstract: There is considerable current interest in developing methods to integrate nanoparticles into optical, electronic, and biological systems due to their unique size-dependent properties and controllable shape. We report herein a versatile new approach for covalent immobilization of nanoparticles onto substrates modified with photoactive, phthalimide-functional, self-assembled monolayers. Upon illumination with UV radiation, the phthalimide group abstracts a hydrogen atom from a neighboring organic molecule, leading to radical-based photografting reactions. The approach is potentially "universal" since virtually any polymeric or organic-inorganic hybrid nanoparticle can be covalently immobilized in this fashion. Because grafting is confined to illuminated regions that undergo photoexcitation, masking provides a simple and direct method for nanoparticle patterning. To illustrate the technique, nanoparticles formed from diblock copolymers of poly(styrene-b-polyethylene oxide) and laden with Hostasol Red dye are photografted and patterned onto glass and silicon substrates modified with photoactive phthalimide-silane self-assembled monolayers. Atomic force microscopy and X-ray photoelectron spectroscopy are applied to characterize the grafted nanoparticle films while confocal fluorescence microscopy is used to image patterned nanoparticle deposition.
authors: Department of Chemistry, Columbia University, 3000 Broadway Avenue, New York, New York 10027, United States.
authors: Ellane J
authors: EJ
authors: Park
authors: Tina
authors: T
authors: Wagenaar
authors: Siyan
authors: S
authors: Zhang
authors: A James
authors: AJ
authors: Link
authors: Robert K
authors: RK
authors: Prud'homme
authors: Jeffrey T
authors: JT
authors: Koberstein
authors: Nicholas J
authors: NJ
authors: Turro
mesh_terms: D003224:Congo Red / Q000737:chemistry; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D010797:Phthalimides / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012825:Silicon / Q000737:chemistry; D013499:Surface Properties; D014466:Ultraviolet Rays
chemical_list: D010797:Phthalimides; D011137:Polystyrenes; D012821:Silanes; C541965:polystyrene-b-poly(ethylene oxide); C037431:phthalimide; D003224:Congo Red; D011092:Polyethylene Glycols; D012825:Silicon