Cover Picture: DNA‐Templated Silver Nanorings (Adv. Mater. 23/2005)

The cover shows that toroidal condensates of duplex DNA can be used as templates for facile preparation of monodisperse nanorings of noble metals. In the work by Zinchenko and co‐workers, reported on p. 2820, conformational transition of long DNA chains from elongated coils into compact toroidal condensates changes the manner of reduced silver deposition, from DNA chain metallization with nanoparticles to the formation of silver rings. A one‐pot, three‐step, simple preparation method leads to formation of well‐defined monodisperse silver nanorings (100 nm in diameter) dispersed in water.     

Cover Picture: Weaving Genetically Engineered Functionality into Mechanically Robust Virus Fibers (Adv. Mater. 6/2007)

The desired functionality of a virus fiber (such as gold‐binding ability) can be programmed by manipulating the M13 virus genome, report Angela Belcher, Krystyn Van Vliet, and co‐workers on p. 826. The background picture is an illustration of a virus fiber that is conjugated with cadmium selenide quantum dots and emits red light when excited by UV irradiation. The genetically tunable functionality on the virus fiber offers a convenient designing process and will bring a variety of new applications to antimicrobial, catalytic, optical, medical, and electronic fibers.     

Cover Picture: Programmable Motion and Separation of Single Magnetic Particles on Patterned Magnetic Surfaces (Adv. Mater. 14/2005)

Structured magnetic surfaces enabling programmable motion of single micrometer‐sized magnetic particles are reported on p. 1730 by Gunnarsson and co‐workers. Patterns of thin‐film magnetic elements are tailored to form transport lines with junctions for the separation of individual particles. This method has the potential to improve and generate new applications in biotechnology. The cover shows a schematic of the transportation and separation of magnetic particles functionalized with antibodies capable of selectively capturing the corresponding analytes from a sample.     

Cover Picture: Surface Wrinkles for Smart Adhesion (Adv. Mater. 4/2008)

A patterned adhesive, based on surface wrinkling through swelling of a laterally confined polymer film, is presented by Alfred J. Crosby and co‐workers on p. 711. The image highlights the interface between the wrinkles (bright cylinders) of the patterned adhesive separating from a glass substrate (circular region). Enhanced control of adhesion is attributed to contact line splitting, which is fundamental to adhesion control in numerous examples in nature, for example, the gecko.     

Cover Picture: Metallodielectric Two‐Dimensional Photonic Structures Made by Electric‐Field Microstructuring of Nanocomposite Glasses (Adv. Mater. 24/2005)

Nanocomposite glasses containing metallic nanoparticles can be microstructured by electric‐field assisted dissolution of the embedded particles. As reported by Graener and co‐workers on p. 2983, any pattern of the electrode—down to the nanoscale—can be transferred onto the nanocomposite glass, giving 2D metallodielectric microstructures. The cover image shows as the background a regular array of squares with 2 μm periodicity produced using macroporous silicon as an electrode. The insets show the base material, the electrode, a representation of the dissolution process, and an enlarged view of the remaining silver nanoparticles.     

Inside Front Cover: One‐Dimensional Plasmon Coupling by Facile Self‐Assembly of Gold Nanoparticles into Branched Chain Networks (Adv. Mater. 21/2005)

Short, single‐particle‐wide chains and complex networks of interconnected chains are easily self‐assembled from 13 nm Au nanoparticles by inducing a surface electrostatic dipolar moment in a controlled manner. Mann and co‐workers further demonstrate both experimentally and theoretically on p. 2553 that efficient surface plasmon coupling takes place in these extensive networks, thus opening a new bottom–up approach to subwavelength optical‐waveguiding devices. The left panel in the image shows isolated 13 nm Au nanoparticles; the back panel, short linear chains; the bottom panel, complex branched network of chains; and the right panel, a graphical rendering of optical spectroscopic properties during the self‐assembly process.     

Cover Picture: Functionalized Gold Nanoparticles Mimic Catalytic Activity of a Polysiloxane‐Synthesizing Enzyme (Adv. Mater. 10/2005)

A system that acts as a biomimetic of the silica‐synthesizing enzyme found in a marine sponge is reported by Morse and co‐workers on p. 1234. Gold nanoparticles (GNPs) are functionalized with the same organic moieties that are found in the enzyme's catalytic site. Interaction between the nucleophilic (OH‐terminated) and hydrogen‐bonding (imidazole‐terminated) GNPs, as shown on the cover, is required for the hydrolysis of a silicon alkoxide precursor and subsequent polycondensation to form silica at a low temperature and near‐neutral pH. Replacement of either of the required functional groups by a non‐reactive methyl group abolishes catalysis in this synthetic system, as it does in the biological enzyme. Cover art provided by Peter Allen.     

Cover Picture: Self‐Assembly of Single‐Walled Carbon Nanotubes into a Sheet by Drop Drying (Adv. Mater. 1/2006)

Drops of a suspension of individual single‐walled carbon nanotubes in F68 Pluronic surfactant dry on glass substrates to form a “crust” at the free surface. The crust is extremely thin (～ 100 nm) and consists of an entangled mesh of nanotubes and Pluronic. Pasquali and co‐workers report on p. 29 that the convective flow associated with the drying preferentially assembles the micelles into a hexagonal arrangement, as revealed by the birefringent pattern shown on the cover. This technique is promising for developing thin, optically transparent, and electrically conductive coatings and films consisting of nanotubes.     

Cover Picture: Polyaniline Nanofibers Prepared by Dilute Polymerization (Adv. Mater. 13/2005)

The cover image shows a scanning electron micrograph of polyaniline/camphorsulfonic acid nanofibers synthesized using dilute polymerization. The inset shows isolated branched nanofibers with diameters of 17–50 nm. On p. 1679, Chiou and Epstein report the preparation of these polyaniline nanofibers with controlled diameters via reducing the concentrations of both monomer and oxidant.     

Cover Picture: Hierarchy Selection,Position Control,and Orientation of Growing Mesostructures by Patterned Surfaces (Adv. Mater. 8/2006)

Spontaneous hierarchical organization of silica by means of a command surface is shown on the cover and described on p. 1055 by Marlow and co‐workers. In this approach, the usual co‐existence of energetically similar structures is overcome, permitting selection of one hierarchical silica structure. A patterned substrate is shown to lead to pixel‐like, simultaneous growth of a hierarchal assembly involving four structural levels. The individual pixels belong to a new class of circularly organized solids.     

Inside Front Cover: Direct Patterning,Conformal Coating,and Erbium Doping of Luminescent nc‐Si/SiO2 Thin Films from Solution Processable Hydrogen Silsesquioxane (Adv. Mater. 21/2007)

Patterned nanostructure arrays of luminescent, oxide‐embedded silicon nanocrystals (nc‐Si) are formed by reductively thermally processing e‐beam patterns of hydrogen silsesquioxane (HSQ). While traditionally employed as a negative type e‐beam resist, HSQ is shown to produce thin films, non‐flat conformal coatings, and sub‐10 nm structures that contain luminescent nc‐Si. The variety of morphologies (structures) that can be produced by this method highlights the versatility of HSQ as a nc‐Si precursor, report Jonathan Veinot and co‐workers from the University of Alberta, Canada on p. 3513.     

Cover Picture: Ductile‐to‐Brittle Transition in Nanocrystalline Metals (Adv. Mater. 16/2005)

Uniaxial tensile studies concerning electrodeposited nanocrystalline face‐centered cubic Ni and Ni–Fe alloys are reported on p. 1969 by Ebrahimi and Li. The nanograined metals display a transition in the deformation mechanism at a critical grain size. The cover shows that their fracture surfaces exhibited a ductile‐to‐brittle transition from the “cup–cup” (intragranular, ductile failure, dislocation controlled) (top panels) to “cup–cone” (intergranular, brittle fracture, probably due to breaking of atomic bonds) (bottom panels) characteristics at room temperature across this critical grain size value.     

Cover Picture: Metal–Silica Hybrid Nanostructures for Surface‐Enhanced Raman Spectroscopy (Adv. Mater. 21/2006)

The image shows an ordered array of silver‐tipped silica nanorods, which serve as a substrate for surface enhanced Raman spectroscopy (SERS). Signal intensities from test molecules in regions of aggregated pillars (indicated by the green laser beam) were enhanced by factors of 10 to 20 compared to arrays of separated pillars, as reported by Moskovits and co‐workers on p. 2829. This hybrid structure maximizes SERS signal intensities from analytes while minimizing the quantities needed for detection due to the precise formation of “hot regions” at the intersection of the silver tips.