New Binuclear Complexes with Mixed Ligands and μ<Subscript>2</Subscript>-Phenol Oxygen Bridges: Synthesis Crystal Structures and Magnetism

Two new complexes, [M₂(L)₂(bpy)₂](ClO₄)₂ [L = methyl salicylate, bpy = 2,2′-bipyridine, M = Cu (1) and Zn (2)] have been synthesized and structurally characterized by X-ray structure analyses. The centrosymmetric dimeric structure consists of a binuclear unit, in which M (M = Cu or Zn) atoms are bridged by two phenol oxygen atoms as a μ ₂-bridged. The neighboring binuclear units interact with each other by two kinds of weak contacts: one kind is π–π stacking by π–σ attraction with an edge-to-face C–H···π interaction, and the second type is a H-bonding interaction, which extends the binuclear unit into a 3D network. Magnetic measurements confirm that 1 presents a very strong intradinuclear ferromagnetic coupling between the copper(II) ions.     

Solvothermal Synthesis, Structure and Optical Property of Nanosized CoSb(3) Skutterudite

Binary skutterudite CoSb₃ nanoparticles were synthesized by solvothermal method. The nanostructuring of CoSb₃ material was achieved by the inclusion of various kinds of additives. X-ray diffraction examination indicated the formation of the cubic phase of CoSb₃. Structural analysis by transmission electron microscopy analysis further confirmed the formation of crystalline CoSb₃ nanoparticles with high purity. With the assistance of additives, CoSb₃ nanoparticles with size as small as 10 nm were obtained. The effect of the nanostructure of CoSb₃ on the UV–visible absorption and luminescence was studied. The nanosized CoSb₃ skutterudite may find application in developing thermoelectric devices with better efficiency.     

Hydrodynamic,optical, and conformational properties of some polybenzimidazoles

Molecular hydrodynamics and optical methods have been employed to study the properties of molecules of polybenzimidazoles in 96% H₂SO₄ and to determine their molecular, conformational, and dynamo-optical characteristics. The temperature dependence has been investigated for the intrinsic viscosity. The equilibrium rigidity of molecular chains has been estimated for the examined polybenzimidazoles.     

Non-plasma ignition of lead styphnate by a semiconductor bridge and its comparison with plasma ignition

The process of non-plasma ignition of lead styphnate by a silicon-based semiconductor bridge is studied. Discharge characteristics with plasma and non-plasma ignition are analyzed. It is demonstrated that non-plasma ignition is characterized by a low energy and can be applied in cases with fine-grain energy materials.     

Fabrication of thick gel-like films by anodizing iron in a novel electrolyte based on dimethyl sulfoxide and H2SiF6

The thick bi-layered gel-like film has been grown by anodizing iron in a novel electrolyte composition based on dimethyl sulfoxide and silica hexafluoride acid (H₂SiF₆) and examined. The thickness of the anodic film composed of the inner orange-colored nanoporous layer and the outer cherry-colored gel-like layer increased at a constant rate up to 40–50 μm depending on the bath composition and anodizing conditions. Under drying and subsequently annealing, the gel layer shrinks and cracks producing hierarchical morphology of thick films mainly composed of hematite (a-Fe₂O₃). Scanning electron microscopy, Mössbauer, Raman and energy dispersive X-ray spectroscopies, and X-ray diffraction have been applied to reveal the composition and morphology of these novel films before and following various post-treatments.     

Determination of conditions for depositing crystalline calcium chloride hydrate on the heat and moisture exchanging layer of breathing filters

The moisture content and hygroscopicity of viscose fiber and filter material of the heat-exchanging layer of a breathing filter were determined as a function of the mass fraction of calcium chloride, drying temperature, and the calcium chloride soaking method in order to define these parameters.     

Core-shell structured nanoassemblies based on β-cyclodextrin containing block copolymer and poly(β-benzyl L-aspartate) via host-guest complexation

Double hydrophilic copolymers (PEG-b-PCDs) with one PEG block and another block containing β-cyclodextrin (β-CD) units were synthesized by macromolecular substitution reaction. Via a dialysis procedure, complex assemblies with a core-shell structure were prepared using PEG-b-PCDs in the presence of a hydrophobic homopolymer poly(β-benzyl l-aspartate) (PBLA). The hydrophobic PBLA resided preferably in the cores of assemblies, while the extending PEG chains acted as the outer shell. Host-guest interaction between β-CD and hydrophobic benzyl group was found to mediate the formation of the assemblies, where PEG-b-PCD and PBLA served as the host and guest macromolecules, respectively. The particle size of the assemblies could be modulated by the composition of the host PEG-b-PCD copolymer. The molecular weight of the guest polymer also had a significant effect on the size of the assemblies. The assemblies prepared from the host and guest polymer pair were stable during a long-term storage. These assemblies could also be successfully reconstituted after freeze-drying. The assemblies may therefore be used as novel nanocarriers for the delivery of hydrophobic drugs.     

Synthesis and characterization of a new amphiphilic copolymer containing multihydroxyl segments for drug carrier

A new amphiphilic copolymer (copoly‐(MR‐BMA‐HEA‐MAA), PRBHM) containing multihydroxyl segments was designed and synthesized for application in drug carrier. PRBHM can be dissolved in water to form aggregates directly with a critical aggregate concentration (CAC) of 0.0138 mg mL^?1. The chains of PRBHM can be collapsed into hydrophobic globules when pH decreases from neutral to slightly acid condition (pH = 5.0–7.0) in water. Since the hydrophilic hydroxyl group is independent on pH, PRBHM can keep stable both in neutral and slightly acid aqueous solutions. The hydrophobic small molecules such as 5‐(4‐(4‐vinylbenzyloxy) phenyl)‐4,5‐dihydro‐1,3‐diphenyl‐1H‐pyrazole (PY) can be loaded into PRBHM aggregates via ultrasonic treatment in water, and can be internalized into BEL‐7402 cancer cells. The cytotoxicity determination also indicates the good biocompatibility of PRBHM in potential application as a drug carrier. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Rheometric study of chitosan/activated carbon composite hydrogels for medical applications using an experimental design

Composite chitosan/activated carbon hydrogels were prepared with the vapor‐induced phase separation process. A rheometric study was performed with a factorial fractional design to determine the formulation and process parameters significantly influencing the mechanical properties of the gels. The results revealed that three factors played a key role in the storage modulus of the gels. According to the model, these factors could be classified with respect to their relative influence on the storage modulus in the following descending order: chitosan concentration > gel time of exposure to ammonia vapors > temperature of the reactor. Increasing these parameters led to an increase in the physical crosslinking density within the matrices and resulted in a reinforcement of the mechanical properties of the hydrogels. Two interactions were also shown to be significant and promoted the formation of supplementary junction zones within the matrix: the first one corresponded to the interaction between the chitosan concentration and the exposure time to ammonia vapors, and the second one concerned the interaction between the chitosan concentration and the temperature of the reactor. A second‐order model was obtained from statistical analysis. Because of the determination coefficient (89.4%) and the P value related to the lack of adjustment of the model (0.043), which was associated with a 95% confidence level, this model could be considered to be of good quality. Three gels were used to validate the model, and good accuracy was obtained. The maximum elastic modulus was obtained with the highest chitosan concentration [4% (w/v)], the highest temperature in the gelation chamber (50°C), and the longest time of exposure to ammonia vapors (24 h). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011