Materials Literature
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We present a theory of interstitial Mn in Mn-doped ferromagnetic semiconductors. Using density-functional theory, we show that under the nonequilibrium conditions of growth, interstitial Mn is easily formed near the surface by a simple low-energy adsorption pathway. In GaAs, isolated interstitial Mn is an electron don…
The recently discovered structural transition in polymerized KC60 at about 50 K results in a doubling of the unit cell volume and accompanies the metal-insulator transition. Here we show that the (a+c,b,a-c) superstructure results from small orientational charge density waves along the polymer chains and concomitant d…
Within the framework of the Landau-Lifshitz-Gilbert equation, using permalloy parameters, we study the statics and dynamics of flat circular magnetic nano-structures with an in-plane magnetic vortex configuration, putting particular emphasis on the (planar) vorticity of the magnetic state and on the (perpendicular) po…
Polyaniline (PANI) samples were synthesized by an ultrasonic irradiation synthesis method and by a magnetic stirring process. The structure of the polyanilines was investigated by using infrared and UV−vis−NIR spectral analysis, X-ray diffraction, transmission electron microscopy, electron diffraction, and elemental a…
The synthesis, characterization, and stability of porphyrin nanoparticles of 20-200 nm diameter presented herein is general for meso arylporphyrins. The elegance of the method lies in its simplicity. This work shows that the agent used to prevent agglomeration can be covalently attached to the dye forming the particle…
Nanostructured polyelectrolyte multilayer thin films electrostatically assembled alternately from such polymers as poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) were investigated for their in vitro cell interactions. Not surprisingly, NR6WT cells, a highly adhesive murine fibroblast cell line, atta…
The fabrication of Ti3SiC2 from five different starting materials was investigated. Pulse discharge sintering (PDS) was employed for a rapid synthesis in a relatively low temperature range. The highest purity of Ti3SiC2 (about 99 wt%) was achieved at the sintering temperature of 1300 °C, which is obviously lower than…
A series of novel chromogenic host compounds based on a diphenylazo core with bulky endgroups and hydrogen bonding capability has been synthesised and shown to exhibit distinct and easily detected colour changes on complexation with guests, allowing for rapid screening of host∶guest complex formation.
Viscosity tuning of preceramic polymers, in order to adapt them to various applications, has been elaborated by the authors. Thermal and photochemical crosslinking adjusts the viscosity of the polyureasilazane Ceraset in the range from 0.05 up to 20 Pas; the low viscous Ceraset can be used for the reaction molding of…
We studied the crystallization behavior in a diblock copolymer/homopolymer blend system exhibiting “dry-brush” phase behavior in the melt. A nearly symmetric poly(ethylene oxide)- block -polybutadiene (PEO- b -PB) was blended with a PB homopolymer (h-PB) having approximately the same molecular weight as that of the PB…
The structural stability of mesoporous molecular sieves organically functionalized by a direct method has been investigated in terms of the stability against moisture treatment and mechanical pressure. Incorporation of organic groups directly attached to Si atoms by the use of organosilanes results in an enhancement o…
Abstract Environmental factors such as oxygen, temperature, and microbial species may have significant effects on decomposition of biodegradable polymers. A representative biodegradable, thermoplastic polymer, poly(3‐hydroxybutyrate‐ co ‐hydroxyvalerate) (PHBV), was decomposed in an aqueous medium under controlled lab…
Summary The surface chemistry of Eucalyptus grandis wood pulp fibres was investigated using the sessile drop apparent contact angle, XPS and TOF-SIMS techniques. Pulp fibres were studied using different chemical pulping conditions. The pulping affected the surface coverage of lignin and extractives, as indicated by XP…
Experiments designed to mimic cell receptor structures on biomaterial surfaces showed that slow evaporation of water-based suspensions containing polystyrene nanospheres created translucent nanostructured films enclosed by highly regular ring shaped patterns. Our finding represents a novel method to functionalize biom…
Covalently cross-linked, three-dimensional nanodomained networks were prepared from radially layered poly(amidoamine−organosilicon) (PAMAMOS) copolymeric dendrimers containing hydrophilic polyamidoamine (PAMAM) interiors and reactive hydrophobic organosilicon (OS) exteriors. Two different types of curing chemistries w…
The dynamics of photoinduced formation of electron and hole centers at the surface of MgO powder has been investigated in situ using EPR spectroscopy. Monochromatic excitation of the sample with 282 nm photons leads to creation of well-separated electron and hole centers at the surface. Polychromatic (200−900 nm) irra…
Reaction of M(OAc)(2).xH(2)O (M = Mn, Cu, or Cd) with di-tert-butyl phosphate (dtbp-H) in a 1:2 molar ratio in methanol followed by slow crystallization of the resultant solid in MeOH/THF medium results in the formation of three new polymeric metal phosphates [M(dtbp)(2)](n)() [M = Mn, 1 (beige); M = Cu, 2 (blue)] and…
Encapsulation of chiral ruthenium porphyrin [RuII(D4-Por*)CO] in modified mesoporous silica supports such as MCM-41 and MCM-48 achieves active catalysts for asymmetric epoxidation of alkenes by 2,6-dichloropyridine N-oxide and intramolecular cyclopropanation, which is the first example of chiral metalloporphyrin suppo…
The novel nickel-substituted, dimeric phosphotungstate [Ni(3)Na(H(2)O)(2)(PW(9)O(34))(2)](11-) (1) has been synthesized and characterized by IR spectroscopy, elemental analysis, and electrochemistry. X-ray single-crystal analysis was carried out on Na(11)[Ni(3)Na(H(2)O)(2)(PW(9)O(34))(2)].21.25H(2)O, which crystallize…
Gold nanoparticles supported on highly hydrophobic ethane bridged Ti incorporated mesoporous organosilica are reported for enhanced vapor phase epoxidation of propene using H2 and O2.