Materials Literature
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The molecular structure of various semi-fluorinated polymers derived from tetrafluoroethylene, hexafluoropropylene, and vinylidenefluoride is examined by different characterization methods in dilute solution. The polymer synthesis was tailored to set up samples with a straight linear topography as well as model polyme…
Abstract New 2 H ‐[1]benzothieno[3,2‐ b ]pyrroles were synthesized by a [1,5]‐sigmatropic shift of 3 H ‐benzothienopyrroles. The dependence of the rearrangement on solvent and temperature was studied. The first merocyanine dyes based on both 3 H ‐ and 2 H ‐benzothienopyrroles were synthesized and characterized by NMR‐…
Teflon® AF is truly a family of amorphous fluoropolymers with an extraordinary combination of properties. All of the excellent properties of the existing fluoropolymers have either been retained or improved upon and properties arising from the amorphous nature and the presence of microvoids in the AF family of polymer…
We report measurements on the radial electromechanical properties of single walled carbon nanotubes. By measuring the conductance of the nanotube, we show that a gap is opened while squashing the nanotubes and that during the deformation stages we observe at least two open-close cycles of the gap. We employ a novel ex…
[reaction: see text] Bridged phenylthienylethenes and dithienylethenes were synthesized via Pd-catalyzed double-cyclization reactions of (Z,Z)-1,6-diaryl-1,5-hexadien-3-ynes. Pd-catalyzed as well as photoinduced Z/E isomerization of the products were also investigated.
Three 3,4-bis(alkylthio)pyrroles ( 5a − c ) were synthesized by a nonclassical pyrrole ring formation reaction followed by alkylation of the dithiol-2-one functional group. UV−vis absorption studies together with time dependent density-functional theory (TD-DFT) computations suggest that the monomers ( 5a − c ) displa…
The dynamics of cis-1,4-polybutadiene (cis-1,4-PB) over a wide range of temperature and pressure conditions is explored by conducting atomistic molecular dynamics (MD) simulations with a united atom model on a 32-chain C128 cis-1,4-PB system. The local or segmental dynamics is analyzed in terms of the dipole moment ti…
Abstract Chitin and chitosan with improved characteristics were produced from shrimp shell waste preconditioned by limited decay or by treatment with 0.016 mol L −1 benzoic acid. Preconditioned shrimp shells were transparent, had a clean surface and were susceptible to demineralization and deproteinization using 0.68…
All of the unique properties imparted by fluorocarbons can be traced back to a single origin: the nature of the C—F bond. These properties include low surface tension, excellent thermal and chemical stability, low coefficient of friction, and low dielectric constant. However, not all of these properties are possessed…
The preparation and characterization of the five-coordinate iron(II) porphyrinate derivative [Fe(TpivPP)(NO3)]- (TpivPP = picket-fence porphyrin) is described. Structural and magnetic susceptibility data support a high-spin state (S = 2) assignment for this species. The anionic axial nitrate ligand is O-bound, through…
Abstract After being subjected to preliminary purification, montmorillonite clay was leached with varying concentrations of sulfuric acid (0.5–2 mol L −1 ) at 90 °C for varying times (0.5–4 h). Acid leaching causes partial amorphization of the montmorillonite and increases its specific surface area by a factor of 3 (f…
The controlled generation of single photons is mandatory for applications in quantum communication, in particular for secure quantum cryptography, and also for a number of fundamental problems in quantum optics. Here, we present a stable all solid-state source for single photons utilizing the fluorescence light from a…
We incorporated cisplatin inside single-wall carbon nanohorns (NHs) and revealed that 70% of the cisplatin was released from NHs having holes with hydrogen-terminated edges when they were immersed in phosphate-buffered saline (PBS). However, only 15% was released from NHs having holes with oxygen-containing functional…
Single-walled carbon nanotubes functionalized by phenyl groups can be sulfonated in oleum (H 2 SO 4, 20% free SO 3 ) to give materials that exhibit high solubility in water as determined by centrifugation in conjunction with UV−vis−near-infrared measurements. Cryo-transmission electron microscopy images show that exte…
The temporal and spectral properties of luminescence from individual CdSe quantum dot-oligophenylene vinylene nanostructures (single quantum dots with conjugated organic ligands coordinated to the surface) are profoundly modified relative to blended films of the same components. These kinds of composite quantum dot-co…
Hexagonal nanodisks of ZnO were fabricated by a solution process using ZnO nanoparticles and their cathodoluminescence characteristics were investigated. Monochromatic cathodoluminescence images showed that luminescence was spatially localized near the boundary of the nanodisk and spectral analysis in conjunction with…
Nanocrystalline Ce(1)(-)(x)Ti(x)O(2) (0 < or = x < or = 0.4) and Ce(1-)(x)(-)(y)Ti(x)Pt(y)O(2)(-)(delta) (x = 0.15, y = 0.01, 0.02) solid solutions crystallizing in fluorite structure have been prepared by a single step solution combustion method. Temperature programmed reduction and XPS study of Ce(1)(-)(x)Ti(x)O(2)…
A fast and reliable method is reported for fabricating superhydrophobic surfaces. The method combines microstructure replication with polymer phase inversion and can be applied to a wide variety of polymers. This method provides a surface that contains roughness on two independently controllable levels, i.e., the micr…
We present here a novel and simple synthetic strategy for fabricating superparamagnetic nanomagnets randomly dispersed in porous carbons. The method can be basically considered as a pyrolysis performed inside the restricted volume formed by the pores of an activated carbon. Such magnetic porous materials exhibit large…
Straightening out chirality: Chiral mesostructured silica nanofibers of MCM-41 with one (see TEM image, the arrows indicate periodic fringes) and two twist axes were fabricated from a simple dilute synthesis system without any chiral additives. A continuous transformation from a chiral mesostructure to an achiral stra…