Materials Literature
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A significant reduction in the glass transition temperature ( T g ) is found for poly( l -(−) lactide) (PLLA), crystallized under partially constrained conditions, where the polymer is prevented from shrinking. It is proposed that the constrained crystallization process results in increasing the net free volume in the…
We explore the possibility that the unusually large electroclinic effect observed in the smectic-A phase of a ferroelectric liquid crystal arises from the presence of an ordered array of disclination lines and walls in a smectic-C* phase. If the spacing of these defects is in the subvisible range, this modulated smect…
Nanomagnets have been created by the incorporation of magnetic clusters into mesoporous silica. It is shown that, for a given cluster, the pore size has a strong influence on the degree of incorporation. Furthermore, the incorporation of these nanoclusters into three-dimensional organized mesoporous silica ensures tha…
Polymeric nanomicelles that allow control of the location of porphyrin moieties in the coronas, cores, or cores and coronas have been designed and reliably constructed by self- assembly of porphyrin-centered star polymers (see Figure). These photofunctional nanomicelles are of interest for advanced materials, pharmace…
High-speed persistent spectral hole burning (PSHB), 30 times faster than in a similar H2 gas treated glass, has been achieved for a samarium(II)-doped alumina–silica glass upon irradiation with X-rays. Glasses of this type, enabling fast and highly efficient hole burning, are excellent candidates for binary high-densi…
Layer-by-layer deposition of polythiophene (see Figure) has successfully been carried out using only polyanion and polycation dilute solutions of polythiophene. The synthesis and characterization of these assemblies, as well as their optical properties, are described. The conductivities of the regioregular polythiophe…
We have experimentally investigated the diameter dependence of Coulomb effects on the optical transition in semiconducting single-walled carbon nanotubes. The absorption band due to the lowest band-to-band transition shifts to the higher-energy side compared to the transition energy calculated by a tight-binding model…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTEncapsulation of Hydrophilic Pincer−Platinum(II) Complexes in Amphiphilic Hyperbranched Polyglycerol NanocapsulesMartijn Q. Slagt, Salah-Eddine Stiriba, Robertus J. M. Klein Gebbink, Holger Kautz, Holger Frey, and Gerard van KotenVi…
Hydrocarbon fuels have specific energy contents some two orders of magnitude greater than any electrical storage device. They therefore proffer an ideal source in the universal quest for compact, lightweight, long-lasting alternatives for batteries to power the ever-proliferating electronic devices. The motivation lie…
The study of poly( n -hexyl methacrylate) has been performed by both thermo-stimulated currents (TSC) and dynamic dielectric spectroscopy (DDS) in order to better define the nature of molecular mobility in the glass transition temperature range. TSC results reveal the existence of three dipolar relaxation modes: α, as…
Abstract The uncatalyzed cure of a commercial tetrafunctional epoxy monomer TGDDM ( N,N,N ′, N ′‐tetraglycidyl‐4,4′‐diaminodiphenylmethane) with hexahydrophthalic anhydride (HHPA), using variable stoichiometric ratios is reported. The reaction was followed by differential scanning calorimetry (DSC). Two kinds of exper…
This paper presents a physico-chemical and an electrical study of a low-density polyethylene used in cable insulation. The first part deals with the effect of temperature on morphology and the consequences on the conduction properties. Next, the influence of cross-linking by-products and antioxidant is studied. The an…
As part of a program to develop resins for high-performance/high-temperature aerospace structural applications, preliminary neat resin properties of naphthylethynyl terminated imide oligomers were determined and compared with the corresponding phenylethynyl terminated imide oligomers. Prior to oligomer work, four naph…
The diffusion coefficient of nickel nitrate dissolved in water in porous silica plates with different pore size was measured to investigate the effect of pore size on the liquid-phase diffusion resistance. The pore-diffusion coefficient of nickel nitrate varied with the pore size of the silica gel. In pores of diamete…
The first catalytic oxidation reactions with cofacial bisporphyrins using molecular oxygen as the terminal oxidant are presented. The photocatalytic reactions proceed under mild conditions (ambient temperature and pressure) without the need for a co-reductant. A systematic reactivity study of the photooxidation of dim…
Iron- and cobalt-exchanged ZSM-5 are active catalysts for the dissociation of nitrous oxide. In this study, density functional theory was used to assess a possible reaction pathway for the catalytic dissociation of N 2 O. The active center was taken to be mononuclear [FeO] + or [CoO] +, and the surrounding portion of…
Polyacrylonitrile/Na−MMT nanocomposites were synthesized through an emulsion polymerization of acrylonitrile (AN) using 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS). The silicate (Na−MMT) layers were exfoliated during polymerization. The nanocomposites were exfoliated up to 20 wt % content of pristine Na−MMT re…
• The ability of the diatom Thalassiosira weissflogii to assimilate inorganic N in darkness is compared with that seen in flagellates. • Experiments were conducted with T. weissflogii grown in N-replete and in N-limiting cultures and the rates and capacity for ammonium and nitrate assimilation were determined. • High…
Abstract In this article, we report on recent investigations on filled natural rubber. These investigations include a mechanical characterization as well as a molecular analysis based on measurements of chain orientation. It is demonstrated that at intermediate strains, the increase in the moduli can be explained by t…
Charge-driven microencapsulation of water-soluble CdTe nanocrystals has been used to create both single-color tagged microspheres (see Figure) and multicolored beads with controlled emission intensity ratios. The concept is based on the pumping of negatively charged species into the interior of specially designed micr…