Sequential chemical deposition of metal alloy jellyfish using polyaniline: redox chemistry at the metal-polymer interface.

We here demonstrate for the first time the fabrication of jellyfish-like Au-Ag alloys through sequential chemical deposition on a PANI substrate. This methodology can be applied to fabricate not only nanoparticles with complex morphology but also alloys with various compositions.

Mechanistic study of silver nanoparticle formation on conducting polymer surfaces.

Conducting polymer (polyaniline) sheets are shown to be active substrates to promote the growth of nanostructured silver thin films with highly tunable morphologies. Using the spontaneous electroless deposition of silver, we show that a range of nanostructured metallic features can be controllably and reproducibly formed over large surface areas. The structural morphology of the resulting metal-polymer nanocomposite is demonstrated to be sensitive to experimental parameters such as ion concentration, temperature, and polymer processing and can range from densely packed oblate nanosheets to bulk crystalline metals.

Surface structure of niobium-doped potassium tantalate KTa(1-x)Nb(x)O3 obtained from helium atom scattering studies.

Helium atom scattering experiments have been carried out on the (001) surface of KTaO(3) doped with 6, 10 and 15% Nb, produced by cleaving in situ single crystal samples. Several phenomena were observed through He atom diffraction measurements, including metastable behavior immediately after cleaving, reconstruction of a fraction of the surface to (2 × 1) domains after thermally cycling the surface temperatures, and the distribution of step heights of terraces at the surface as multiples of the unit cell dimension of ∼ 4 Å. In addition, a large hysteresis effect was found in the (100) azimuth in the variation of surface reflectivity with surface temperature; a much smaller hysteresis effect was found in the (110) azimuth.

Integration of nanowire devices in out-of-plane geometry.

We report the fabrication of arrays of single and multiple out-of-plane nanowire devices on a single substrate, an important step for the fabrication of novel three-dimensional devices and the integration of individually addressable nanowires onto current Si planar technology platforms. Vertical nanowire device fabrication can greatly increase device densities; however integrating such devices into arrays with registry to the substrate requires precise control over the number and position of the nanowires. Here we report the directed assembly of gold nanoparticle seeds into patterned arrays for the growth of nanowires using chemical recognition and electrophoretic methods.

Formation and dynamics of supported phospholipid membranes on a periodic nanotextured substrate.

We have studied and modeled the morphology and dynamics of fluid planar lipid bilayer membranes supported on a textured silicon substrate. The substrate is fabricated to have channels on its surface that are a few hundred nanometers across, with a channel depth of a few hundred nanometers perpendicular to the plane of observation. Using atomic force microscopy and quantitative fluorescence microscopy, we have shown that the bilayer assemblies conform to the underlying nanostructured substrate.