Metal, metal oxide, and plastic surfaces were modified with poly(vinylpyridine) using adsorption, spin-coating, and dip-coating techniques and various metal, semiconductor, and dielectric nanoparticles were subsequently attached. Prior to the modification, the substrates were treated with glow discharge plasma for cleaning purposes and to introduce surface functional groups that are capable of interaction with the polymer. UV−vis absorption spectroscopy, atomic force, and electron scanning microscopies were used to characterize polymer layers and layers of immobilized nanoparticles. The surface modification with poly(vinylpyridine) via adsorption technique is suggested as a simple, effective, and highly versatile method for the preparation of single, mixed, and multilayered assemblies of various nanoparticles on different substrates.

Silver nanoparticles arranged in two-dimensional arrays experience quadrupolar coupling of plasmon resonances when irradiated with visible light. This coupling leads to the formation of the coherent plasmon mode characterized by an intense narrow resonance in the blue spectral range in the extinction spectrum. The coupling and the intensity of this mode can be effectively controlled by varying the distance between particles. The interparticle distance was varied by biaxial stretching of the arrays prepared in transparent elastomeric film of poly(dimethylsiloxane). The observed phenomenon exemplifies a generic approach in which new optical properties of materials can be engineered by organizing metal nanoparticles in various one-, two-, and three-dimensional structures. Further development of this approach will result in the discovery of novel principles of both fundamental and practical importance.

Silver nanoparticles, self-assembled in two-dimensional arrays on quartz and silicon surfaces, were coated with poly(dimethylsiloxane) (PDMS). After peeling off the surface, resin films contained embedded nanoparticles in their original arrangement. Films with nanoparticles are transparent, flexible, and mechanically stable. The embedded nanoparticles were etched away, producing nanocavities in PDMS. The described method can be used to produce highly robust assemblies of metal, semiconductor, and dielectric nanoparticles on flexible substrates.

A reversible locking mechanism is established for the generation of anisotropic nanostructures by a magnetic field pulse in liquid matrices by balancing the thermal energy, short-range attractive and long-range repulsive forces, and dipole-dipole interactions using a specially tailored polymer shell of nanoparticles. The locking mechanism is used to precisely regulate the dimensions of self-assembled magnetic nanoparticle chains and to generate and disintegrate three-dimensional (3D) nanostructured materials in solvents and polymers.

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We consider two-component suspensions of non-magnetic and magnetic rods and show that alignment of the magnetic component by a magnetic field orients the non-magnetic one. We studied suspensions of non-magnetic V 2 O 5 rods doped with magnetic Fe 3 O 4 nanoparticles. In the isotropic phase, the fieldinduced orientation of Fe 3 O 4 particle chains aligns the V 2 O 5 rods. Moreover, the nematic phase reorients towards the field at z50 Oe, much less than the z5 kOe needed for pure V 2 O 5 suspensions.Such effects should exist in any suspension of two kinds of rods, one of which is sensitive to an external field.

The silver island films were vacuum deposited at two different evaporation rates on unmodified indium tin oxide substrates and the substrates modified with molecules containing thiol, pyridyl, and fluorocarbon groups. The films were characterized by UV-visible spectroscopy and scanning electron microscopy. Large variations in the structure and thickness of the island films that were observed between substrates were rationalized in terms of different chemical affinity of the surfaces to the silver metal.

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