Synthesis and characterisation of Gd2O3 nanocrystals functionalised by organic acids

Nanocrystals of Gd2O3 have been prepared by various methods, using, e.g., trioctylphosphine oxide (TOPO), diethylene glycol (DEG) or glycine. The crystalline particles were of sizes 5 to 15 nm. Different carboxylic acids, e.g., oleic acid or citric acid, were adsorbed onto the surface of the particles made with DEG. IR measurements show that the molecules coordinate to the Gd2O3 surface via the carboxylate group in a bidentate or bridging manner. The organic-acid/particle complexes were characterised by XRPD, TEM, FTIR, Raman, and XPS.     

Synthesis of mesoporous silica materials with ascorbic acid as template via sol-gel process

Mesoporous silica materials with pore diameters of 2-5 nm have been prepared using ascorbic acid as a nonsurfactant template or pore-forming agent in HCl-catalyzed sol-gel reactions of tetraethylorthosilicate,followed by removing the ascorbic acid compound by extraction with ethanol.Characterization results from nitrogen sorption isotherm,powder X-ray diffraction and transmission electron microscopy indicate that the materials have large specific surface areas (e.g.1000 m2/g) and pore volumes (e.g.0.8 cm3/g).The rnesoporosity is arisen from interconnecting disordered wormlike channels and pores with relatively broad size distributions.As the ascorbic acid concentration is increased,the pore diameters and pore volumes of the materials increase.     

Tailor‐made polymer supports via metathesis polymerization: concepts and applications

Ring opening metathesis polymerization (ROMP) and alkyne polymerization have been applied to the preparation of surface‐functionalized inorganic and organic supports using various coating, grafting, precipitation and bulk‐polymerization techniques. Well‐defined carrier materials in terms of particle diameter, specific surface, pore volume and functionalization have been prepared. The resulting materials have been used for applications in heterogeneous catalysis (e.g. Heck couplings) as well as in bioanalytical (e.g. protein) separations.     

Preparation of thin layer materials with macroporous microstructure for SOFC applications

A facile and versatile method using polymethyl methacrylate (PMMA) microspheres as pore formers has been developed to prepare thin layer oxide materials with controlled macroporous microstructure. Several mixed oxides with fluorite and perovskite-type structures, i.e. doped zirconia, ceria, ferrites, manganites, and NiO-YSZ composites have been prepared and characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and mercury porosimetry. The synthesised materials are nanocrystalline and present a homogeneous pore distribution and relatively high specific surface area, which makes them interesting for SOFC and catalysis applications in the intermediate temperature range.     

Recent developments in radiometric and mass spectrometry methods for marine radioactivity measurements

The most important recent developments in radiometric techniques have been the operation of high efficiency HPGe detectors with anticosmic or antiCompton shielding often placed underground, ship-board measurements of ²³⁴Th using gamma-spectrometry or beta-counting and underwater gamma-spectrometry. In mass spectrometry techniques, the availability of high resolution ICP-MS and applications of AMS for the analysis of long-lived radionuclides have opened doors for investigations which previously required too large samples, or were not possible because of lack of sensitivity. These developments are illustrated by several examples of marine radioactivity studies, which include contaminated sites (e.g., Fangataufa Atoll) and open ocean studies (e.g., the Atlantic Ocean) as well as analyses of IAEA reference materials. A comparison of Pu results obtained by alpha-spectrometry, ICP-MS and AMS has shown that a reasonably good agreement has been obtained between all three methods.     

Composite Materials of Synthetic Mordenite and AgI

Composite materials made up of silver iodide and synthetic mordenite in sodium Na-MD or potassium form K-MD have been prepared by sintering a mixture of silver iodide and Na-MD or K-MD, by modified way of preparation. The prepared composites Na-MD/AgI and K-MD/AgI were characterised by X-ray powder diffractometry and thermal analysis. By integrating certain X-ray peaks quantitative reaction values were obtained. The composite Na-MD/AgI with 19 wt% of AgI content was also characterised by EDS analysis and ac conductivity measurements.     

Synthesis and characterisation of 3-armed dendritic molecules with triphenylbenzene or triphenyltriazine as core and triphenylene derivative as shells

Two series 3-armed dendritic molecules with their 1,3,5-tris(4-methyloxyphenyl) benzene or 2,4,6-tris(4- hydroxylphenyl)-1,3,5-s-triazine core and triphenylene derivative shells connected by soft hydrocarbon chains have been synthesised and fully characterised. Whether liquid crystal (LC) or photoluminescence materials have been tuned by changing the length of the soft chain and they have been studied by POM, DSC, XRD, UV-Vis and PL. The results show that all the new dendritic compounds display UV to blue fluorescence in solvents such as DCM, THF and acetone. The TC3 compound bearing 1,3,5-tris(4-hydroxylphenyl) benzene core exhibits LC property with rectangular columnar phase (Col_r) on cooling.     

SYNTHESIS OF MESOPOROUS POLY(STYRENE-co-MALEIC ANHYDRIDE)/SILICA HYBRID MATERIALS VIA A NONSURFACTANT-TEMPLATED SOL-GEL PROCESS*

Mesoporous poly (styrene-co-maleic anhydride)/silica hybrid materials have been prepared. The synthesis wasachieved by the HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and styrene-maleic anhydride copolymerin the presence of 3-aminopropyl triethoxysilane (APTES) as a coupling agent and citric acid as a nonsurfactant template orpore-forming agent, followed by ethanol extraction. Characterization results from nitrogen sorption isotherms and powder X-ray diffraction indicate that polymer-modified mesoporous materials with large specific surface areas (e.g. 900 m~2/g) andpore volumes (e.g. 0.6 cm~3/g) could be prepared. As the citric acid concentration is increased, the specific surface areas, porevolumes and pore diameters of the hybrid materials increase.     

Novel platinum(II)-based anticancer complexes and molecular hosts as their drug delivery vehicles

Platinum(II)-based DNA intercalators where the intercalating ligand is 1,10-phenanthroline or a phenanthroline derivative and where the ancillary ligand is either achiral (e.g. ethylenediamine) or chiral (e.g. diaminocyclohexane) show a range of cytotoxicities with a defined structure-activity relationship. The most cytotoxic are those that contain methylated-phenanthroline ligands and 1S,2S-diaminocyclohexane (S,S-dach) as the ancillary ligand. We have developed a new purification method using Sep-Pak C-18 reverse phase columns, which means these metal complexes can be made faster and cheaper compared to published methods. Platinum(II)-based complexes containing imidazole, pyrrole and beta-alanine subunits, that are capable of recognising specific DNA base-pair sequences have also been synthesised. These include linear or hairpin polyamide ligands that can recognise DNA sequences up to seven base-pairs in length and contain single platinum centres capable of forming monofunctional adducts with DNA. We have now synthesised and characterised, by (1)H and (195)Pt NMR, ESI-MS and elemental analysis, the first dinuclear platinum(II) DNA sequence selective agent. Finally, using (1)H NMR we have examined the encapsulation of our platinum(II)-based DNA intercalators by cucurbit[6]uril (CB[6]). Encapsulation by CB[6] was found to not significantly change the cytotoxicity of five platinum(II)-based DNA intercalators, indicating it may have utility as a molecular carrier for improved drug delivery.     

Metallopolymer-peptide hybrid materials: synthesis and self-assembly of functional, polyferrocenylsilane-tetrapeptide conjugates

Conjugates of poly(ferrocenyldimethylsilane) (PFDMS) with Ac-(GA)(2)-OH, Ac-A(4)-OH, Ac-G(4)-OH and Ac-V(4)-OH have been prepared by reaction of the tetrapeptide units with the amino-terminated metallopolymer. The number average degree of polymerisation (DP(n)) of the PFDMS was approximately 20 and comparable materials with shorter (DP(n) ≈ 10) and/or amorphous chains have been prepared by the same procedure. Poly(ferrocenylethylmethylsilane) (PFEMS) was employed for the latter purpose. All conjugates were characterised by GPC, MALDI-TOF?MS, NMR and IR spectroscopy. With the exception of Ac-V(4)-PFDMS(20), all materials exhibited some anti-parallel β-sheet structure in the solid state. The self-assembly of the conjugates was studied in toluene by DLS. The vast majority of the materials, irrespective of peptide sequence or chain crystallinity, afforded fibres consisting of a peptidic core surrounded by a PFS corona. These fibres were found in the form of cross-linked networks by TEM and AFM. The accessibility of the chemically reducing PFS corona has been demonstrated by the localised formation of silver nanoparticles on the surface of the fibres.     

Complete characterisation of lanolin steryl esters by sub-ambient pressure gas chromatography-mass spectrometry in the electron impact and chemical ionisation modes

Steryl esters occurring in lanolin have been characterised by sub-ambient pressure gas chromatography coupled to mass spectrometry. Electron impact and chemical ionisation modes with different reagent gases have been evaluated in order to carry out unambiguous peak identification. Steryl esters with different sterol (i.e. cholesterol, lanosterol and dihydrolanosterol) and acid moieties either according to carbon number (i.e C₁₀–C₂₃) or isomeric forms (i.e. normal, iso and anteiso) have been identified. Identification of the sterol and acid moieties has been carried out by means of the mass spectral information obtained in the electron impact, chemical ionisation mode either in the positive or negative modes using methane, isobutane and ammonia as reagent gases. Isomeric identification has been achieved by chromatographic retention parameters (i.e. entire-chain length and fractional-chain length) and by the free fatty acid profile also present in lanolin.     

Application of the glow discharge mass spectrometry (GDMS) for the multi-element trace and ultratrace analysis of sputtering targets

Glow discharge mass spectrometry using a VG9000 high resolution mass spectrometer has been applied to both the multi-element trace and ultra trace analyses of sputtering target materials, i.e. aluminium-based alloys, cobalt-based alloys, titanium and platinum. Element dependent relative sensitivity factors (RSF) have been determined using reference materials in order to provide the possibility for quantitative analyses. Aluminium-based and cobalt-based alloys have been extensively analysed to demonstrate precision of GDMS analyses. Detection limits in the ng/g and sub-ng/g ranges, i.e. 0.2 ng/g for U and Th have been determined in aluminium-based alloys. Comparative analyses for alloy components in cobalt-based alloys as well as trace concentrations in titanium have been performed. GDMS has been also applied to multi-element depth profile analyses in contaminated and noncontaminated platinum targets.     

Functional nanocomposites for energy storage: chemistry and new horizons

Energy storage devices are one of the hot spots in recent years due to the environmental problems caused by the large consumption of unsustainable energy such as petroleum or coal. Capacitors are a common device for energy storage, especially electrical energy. A variety of types including electrolytic capacitors, mica capacitors, paper capacitors, ceramic capacitors, film capacitors, and non-polarized capacitors have been proposed. Their specific applications depend on their intrinsic properties. Dielectric capacitors have reasonable energy storage density, with current research focusing on the enhancement of energy density and making the materials more flexible as well as lightweight. Improvement strategies are based on the premise that use of two or more different materials (e.g. polymers and ceramics/metals) at an optimal formulation can result in properties that combine the advantages of the precursor materials. Different polymers especially fluoropolymers (e.g. PVDF and PVDF based co-polymer) are the main components in dielectric nanocomposites for capacitors with high energy storage performance. In this article, we have briefly summarized the recent advances in functional polymers nanocomposites for energy storage applications with a primary focus on polymers, surface engineering, functional groups and novel synthesis/manufacturing concepts applied to new materials. The article presents a unique integrated structure and approaches providing key knowledge for the design and development of novel, low-cost, multifunctional next-generation energy storage materials with improved efficiency.     

Synthesis and properties of sol-gel submicron silica powders doped with partly oxidized iron particles

Magnetic powders based on metallic iron crystallites encapsulated in submicron-sized spherical silica particles have been obtained and investigated. The metallic iron clusters have been produced by the exploding wire method. The silica shells have been prepared via the modified sol-gel Stöber method and the metallic particles have been entrapped by occlusion during the silica powder formation. The entrapped iron particles are partially oxidized due to the nature of the synthetic methods employed. The obtained hybrid materials have been investigated by electron microscopy, X-ray diffraction, magnetic and ζ-potential techniques. Such materials can be employed in such applications as e.g. magnetically-controlled drug vectors or electromagnetic field-shielding.     

Synthesis and characterisation of poly(arylene sulphides)—Part 1: Poly(phenylene sulphide), poly(2-methyl phenylene sulphide) and poly(2,6-dimethyl phenylene sulphide)

A facile synthesis of poly(phenylene sulphide) (PPS), poly(2-methyl phenylene sulphide) (PMPS) and poly(2,6-dimethyl phenylene sulphide) (PDMPS) by solution polymerisation of the respective copper(I)-4-bromothiophenoxides at atmospheric pressure is described. Conditions have been optimised for the preparation of high molecular weight materials and these have been characterised prior to studies of their curing behaviour and thermal-oxidative degradation.     

Calibration of a quenching and deformation differential dilatometer upon heating and cooling: Thermal expansion of Fe and Fe-Ni alloys

Dilatometry is a technique for precise measurement of thermal dilatation of materials during heating or cooling. A procedure has been presented for calibration of a differential dilatometer operating with electromagnetic heating for metallic specimens both upon heating and cooling as well as under uniaxial compressive and tensile loading. The dilation signal has been calibrated for both heating and cooling and for uniaxial loading (compressive and tensile) using platinum or iron reference specimens, for which recommended dilational data are available. The ferro- to paramagnetic transition (characterised by the Curie temperature) of pure iron or iron-based alloys has been adopted to calibrate the temperature in the dilatometric measurement under different loading modes during heating and cooling. On this basis calibrated data for the thermal expansion coefficients of Fe and Fe-Ni alloys have been obtained.     

Folic acid-conjugated nanostructured materials designed for cancer cell targeting

Shell cross-linked nanoparticles (SCKs) constitute a unique class of materials with amphiphilic core-shell morphology; SCKs are characterised by their structural integrity and available functionality to attach receptor-recognising or receptor-specific ligands on the shell surface and, therefore, hold great potential in drug delivery applications; in an attempt to develop novel, cancer cell specific delivery vehicles, folate receptor targeted SCKs have been prepared.     

Ultralow-density nanostructured metal foams: combustion synthesis, morphology, and composition

The synthesis of low-density, nanoporous materials has been an active area of study in chemistry and materials science dating back to the initial synthesis of aerogels. These materials, however, are most often limited to metal oxides, e.g., silica and alumina, and organic aerogels, e.g., resorcinol/formaldehyde, or carbon aerogels, produced from the pyrolysis of organic aerogels. The ability to form monolithic metallic nanocellular porous materials is difficult and sometimes elusive using conventional methodology. Here we report a relatively simple method to access unprecedented ultralow-density, nanostructured, monolithic, transition-metal foams, utilizing self-propagating combustion synthesis of novel transition-metal complexes containing high nitrogen energetic ligands. During the investigation of the decomposition behavior of the high-nitrogen transition metal complexes, it was discovered that nanostructured metal monolithic foams were formed in a post flame-front dynamic assembly having remarkably low densities down to 0.011 g cm(-3) and extremely high surface areas as high as 270 m(2) g(-1). We have produced monolithic nanoporous metal foams via this method of iron, cobalt, copper, and silver metals. We expect to be able to apply this to many other metals and to be able to tailor the resulting structure significantly.     

Pyridinium CH...anion and pi-stacking interactions in modular tripodal anion binding hosts: ATP binding and solid-state chiral induction

The preparation of two new tripodal "pinwheel" type anion hosts based on a triethylbenzene core and bipyridinium or ethylnicotinium arms is reported. The new materials bind anions via CH...anion interactions. Complexes with Br(-) and PF(6)(-) have been characterised by X-ray crystallography as both solvates in a pure form. In the bipyridinium host CH...F interactions to PF(6)(-) induce a chiral C(3) symmetric conformation that is disrupted in the hydrate. The compound is also selective for ATP(2-) in aqueous acetonitrile.     

A feasibility study on the use of Li(4)V(3)O(8) as a high capacity cathode material for lithium-ion batteries

Li(4)V(3)O(8) materials have been prepared by chemical lithiation by Li(2)S of spherical Li(1.1)V(3)O(8) precursor materials obtained by a spray-drying technique. The over-lithiated vanadates were characterised physically by using scanning electron microscopy (SEM) and X-ray diffraction (XRD), and electrochemically using galvanostatic charge-discharge and cyclic voltammetry measurements in both the half-cell (vs. Li metal) and full-cell (vs. graphite) systems. The Li(4)V(3)O(8) materials are stable in air for up to 5 h, with almost no capacity drop for the samples stored under air. However, prolonged exposure to air will severely change the composition of the Li(4)V(3)O(8) materials, resulting in both Li(1.1)V(3)O(8) and Li(2)CO(3). The electrochemical performance of these over-lithiated vanadates was found to be very sensitive to the conductive additive (carbon black) content in the cathode. When sufficient carbon black is added, the Li(4)V(3)O(8) cathode exhibits good cycling behaviour and excellent rate capabilities, matching those of the Li(1.1)V(3)O(8) precursor material, that is, retaining an average charge capacity of 205 mAh g(-1) at 2800 mA g(-1) (8C rate; 1C rate means full charge or discharge of a battery in one hour), when cycled in the potential range of 2.0-4.0 V versus Li metal. When applied in a non-optimised full cell system (vs. graphite), the Li(4)V(3)O(8) cathode showed promising cycling behaviour, retaining a charge capacity (Li(+) extraction) above 130 mAh g(-1) beyond 50 cycles, when cycled in the voltage range of 1.6-4.0 V, at a specific current of 117 mA g(-1) (C/3 rate).