Using light to covalently immobilize and pattern nanoparticles onto surfaces.

Ellane J Park, Tina Wagenaar, Siyan Zhang, A James Link, Robert K Prud'homme, Jeffrey T Koberstein, Nicholas J Turro

Department of Chemistry, Columbia University, 3000 Broadway Avenue, New York, New York 10027, United States.

Langmuir : the ACS journal of surfaces and colloids 2012 Jul 24

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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.

Citation

Ellane J Park, Tina Wagenaar, Siyan Zhang, A James Link, Robert K Prud'homme, Jeffrey T Koberstein, Nicholas J Turro. Using light to covalently immobilize and pattern nanoparticles onto surfaces. Langmuir : the ACS journal of surfaces and colloids. 2012 Jul 24;28(29):10934-41