Materials Literature
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Organic polymers, such as poly(vinyl alcohol), poly(vinyl pyrrolidone), and poly(styrene), were intercalated into single-walled carbon nanotube sheets by soaking the sheets in polymer solutions. Even for short soak times, significant polymer intercalation into existing free volume was observed. Tensile tests on interc…
Wetting behavior was studied on surfaces with a single, circular heterogeneous island. Lyophobic islands were created on lyophilic Si wafers using polystyrene. Alternately, lyophobic perfluoroalkoxy fluoropolymer film was etched to make lyophilic domains. Contact angles and hysteresis were measured with water and hexa…
We describe experimental investigations of the structure of two-dimensional spherical crystals. The crystals, formed by beads self-assembled on water droplets in oil, serve as model systems for exploring very general theories about the minimum-energy configurations of particles with arbitrary repulsive interactions on…
A nano gold rush: Nanoscale gold clusters on oxide surfaces exhibit unique catalytic activity (▴; R=chemical reactivity). The factors for these remarkable nanocatalytic properties are 1) structural dynamical fluxionality, 2) quantum size effects, 3) charge transfer from the support to the clusters, and 4) impurity dop…
A phenotype-centered view of evolution needs to start with a solid idea about the nature of the phenotype. This chapter and the next are devoted to two universal properties of phenotypes, plasticity, or responsiveness to environmental inputs; and modularity, or subdivision into semi-independent and dissociable parts (…
This paper describes a procedure based on electrospinning for generating nanofibers of anatase with controllable diameters and porous structures. When an ethanol solution containing both poly(vinyl pyrrolidone) (PVP, M w ≈ 1 300 000) and titanium tetraisopropoxide was injected through a needle under a strong electrica…
Most catalysts consist of nanometer-sized particles dispersed on a high-surface-area support. Advances in characterization methods have led to a molecular-level understanding of the relationships between nanoparticle properties and catalytic performance. Together with novel approaches to nanoparticle synthesis, this k…
Enhancement of polarization and related properties in heteroepitaxially constrained thin films of the ferroelectromagnet, BiFeO3, is reported. Structure analysis indicates that the crystal structure of film is monoclinic in contrast to bulk, which is rhombohedral. The films display a room-temperature spontaneous polar…
In the present work, we have applied first principles quantum mechanical techniques to the study of periodic models of four silica polymorphs containing different proportions of germanium as a substitutional species: α-quartz, β-quartz, α-cristobalite, and stishovite (rutile); except for β-quartz, which is considered…
After a strong electric bias field is applied to the polyester glass Mylar at temperatures in the mK range, its dielectric constant increases and then decays logarithmically in time. We observed its dielectric response for several temperatures and different field sweeps. Starting from the dipole gap theory, we develop…
Abstract Invertase from Saccharomyces cerevisiae was immobilized on celite and on polyacrylamide by an absorption procedure. The properties of the immobilized invertase were characterized and compared with those of soluble invertase. The activity yield for immobilized invertase on celite and on polyacrylamide was 92%…
Hydrogen is the lightest element. At ambient conditions on a volume basis it stores the least amount of energy compared to other fuel carriers such as natural gas and gasoline. For hydrogen to become a practical fuel carrier, a way must be found to increase its volumetric energy density to a practical level. Present t…
The paper presents Nitinol, a Nickel-Titanium shape memory alloy, as a smart material for medical implants and devices. The atomistic nature of shape memory and superelasticity of Nitinol and the associated unique changes in mechanical properties are described. The smartness of the material is exemplified by its use f…
Mesoporous gold−silica nanocomposites have been synthesized through simple one-step sol−gel reactions of tetraethyl orthosilicate (TEOS) with a gold sol in the presence of dibenzoyl tartaric acid (DBTA) as a nonsurfactant template. The gold nanoparticles were incorporated into the three-dimensional silica network thro…
Cadmium selenide nanorods, unique nanostructures which possess bright and up to 100% polarized photoluminescence, now can be arranged unidirectionally in a single line. The method is based on the chemical attachment of nanorods to the surface of a single cleaved semiconductor nanolayer and exploits a combination of we…
A novel approach to hyperbranched polymers is presented in this work. Hyperbranched polyesters with a large amount of terminal hydroxyl groups are prepared by a one-pot synthesis from commercially available AB-type and CD(n)-type monomers (n >/= 2). In this paper, Michael addition of diethanolamine (CD(2)) or N-methyl…
Unusual arrangements of nanoparticles were observed during the synthesis and subsequent dissolution of PbS particles under the action of the surfactant sodium dodecyl sulfate (SDS) in solutions containing hydrophilic polymers. At the selected polymer and surfactant concentrations, the surfactant forms the insoluble le…
An unprecedented combination of photochromism and electrochromism is observed for two 1,2-bis(dithienyl)cyclopentene derivatives; the ring-opening reactions are photochemically driven while the ring-closing reactions can be triggered by electrochemical oxidation.
We describe the influence of particle concentration on the formation of crystals from soft colloidal particles. Specifically, laser scanning confocal and differential interference contrast microscopies are used to directly observe the packing in entropic crystals formed from submicron-sized particles composed of the t…
We investigate the jump motion among potential energy minima of a Lennard-Jones model glass former by extensive computer simulation. From the time series of minima energies, it becomes clear that the energy landscape is organized in superstructures called metabasins. We show that diffusion can be pictured as a random…