Chemistry Commons^™

Electrodeposition And Characterisation Of Copolymers Based On Pyrrole And 3,4-Ethylenedioxythiophene In Bmim Bf4 Using A Microcell Configuration, Lavinia Astratine, Edmond Magner, John Cassidy, Tony Betts

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Electrochemical copolymerization of pyrrole (Py) and 3,4-ethylenedioxythiophene (EDOT) was performed in an ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, (BMIM BF4) employing a ‘micro-cell’ in order to use the materials efficiently. Characterization of the copolymers formed on an ITO substrate was performed for different Py: EDOT ratios (1:2, 1:1, 2:1) in both aqueous and ionic liquid electrolytes. Electrochemical and spectroelectrochemical analysis revealed that the properties of the copolymer depend upon the Py/EDOT monomer ratio used. The copolymer PPy-co-PEDOT (2:1) displayed good stability, a switching time of 20 s and a colouration efficiency of 101.3 C-1cm2. The presence of Py in the copolymer stabilised …

Using Structure-Based Organic Chemistry Online Tutorials With 2 Automated Correction For Student Practice And Review, Timothy O'Sullivan, Gráinne Hargaden

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This article describes the development and implementation of an open-access organic chemistry question bank for online tutorials and assessments at University College Cork and Technological University Dublin. SOCOT (structure-based organic chemistry online tutorials) may be used to supplement traditional small-group tutorials, thereby allowing students to develop essential problem-solving skills in organic chemistry. This online approach may be used for both formative and summative assessment. Students complete one problem set weekly or fortnightly, which consists of a number of questions of varying difficulty. A wide range of question types is possible; for example, prediction of reaction products, identification of reaction intermediates …

In Vitro Oxygen Availability Modulates The Effect Of Artesunate On Hela Cells, James Murray, Sandra Gannan, Sarah Rawe, James Murphy

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Background/Aim: Hypoxia can affect chemo - therapeutic drug efficacy in cancer patients, yet related in vitro assays in oxygen-rich environment remain the norm. Such levels are well beyond normoxic/hypoxic levels typically experienced by normal tissues/tumor masses. The present study evaluated how artesunate anti-tumor efficacy is modulated by oxygen availability in HeLa cells and its implications for future in vitro analyses. Materials and Methods: Real-time cell analysis was employed to evaluate HeLa cell toxicity to artesunate at 21%, 4% or 1% oxygen. Cell count analysis was performed to validate real-time data. Results: An increase in artesunate efficacy was observed when oxygen …

Progress In Zeolite Synthesis Promotes Advanced Applications, Moussa Zaarour, Biao Dong, Izabela Naydenova, Richard Retoux, Svetlana Mintova

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This article outlines the importance of zeolite synthesis and their unique physicochemical characteristics promoting advanced applications. The main strategies for preparation of zeolites including organic-template assisted, organic-template free and alternative procedures are considered for synthesis of crystallites offering control and fine-tuning of their properties. Besides, rational design of zeolites with pre-determined structure, porosity, size, morphology, and composition are more viable by studying carefully the chemical and physical parameters controlling the zeolite synthesis and understanding the crystallization mechanism. Finally, a particular attention to the preparation of zeolites with nanosized dimensions and their utilization in innovative applications including photovoltaic, medicine and holographic …

Concern-Driven Integrated Toxicity Testing Strategies For Nanomaterials - Report Of The Nanosafety Cluster Working Group 10, Hugh Byrne, Agnes G. Oomen, Peter M.J. Bos, Teresa F. Fernandes, Kerstin Hund-Rinke, Diana Boraschi, Karin Aschberger, Stefania Gottardo, Frank Von Der Kammer, Dana Kühnel, Danail Hristozov, Antonio Marcomini, Lucia Migliore

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Bringing together topic-related European Union-(EU)-funded projects, the so-called “NanoSafety Cluster” aims at identifying key areas for further research on risk assessment procedures for nanomaterials (NM). The outcome of NanoSafety Cluster Working Group 10, this commentary presents a vision for concern-driven integrated approaches for the (eco-)toxicological testing and assessment (IATA) of NM. Such approaches should start out by determining concerns, i.e. specific information needs for a given NM based on realistic exposure scenarios. Recognized concerns can be addressed in a set of tiers using standardized protocols for NM preparation and testing. Tier 1 includes determining physico-chemical properties, non-testing (e.g. structure …

A Simple Inexpensive Method For The Rapid Testing Of The Photocatalytic Activity Of Self Cleaning Surfaces, Andrew Mills, James Hepburn, David Hazafy, Christopher O'Rourke, Josef Krysa, Michal Baudys, Martin Zlamal, Hana Bartkova, Claire Hill, Kim Winn, Morten Simonsen, Erik Sogaard, Suresh Pillai, Nigel Leyland, Rachel Fagan, Frank Neumann, Christina Lampe, Tobias Graumann

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A rapid semi-quantitative, inexpensive method,using a simple digital scanner and an indicator ink, suitable for use in the laboratory, or in the field, for assessing the photocatalytic activity of commerical photocatalytic self-cleaning materials such as glass, is described. The repeatability of the current method is found to be hight and better than many of the previously reported ISO photocatalyst tests.

Synthesis Of Orthogonally Protected 1,2-Diaminopropanoic Acids By Ring-Opening Of 3-Unsubstituted N-Activated Aziridine 2-Carboxylates With Para-Methoxybenzylamine: A Study Of The Regioselectivity Of The Reaction, Fintan Kelleher, Keith O'Brien

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Orthogonally protected 1,2-diaminopropanoic acids (DAPs) have been synthesised in good yields by the ring-opening of 3-unsubstituted N-activated aziridine 2-carboxylates with para-methoxybenzylamine. The choice of both the N-activating group and ester alkyl group had a significant influence on the ratio of attack at the a or b positions of the aziridine. However, the regiochemical outcome is not predictable.

Utilising Caging Techniques To Investigate Metal Assimilation In Nucella Lapillus, Mytilus Edulis And Crassostrea Gigas At Three Irish Coastal Locations, Michelle Giltrap, Ailbhe Macken, Maria Davoren, Evin Mcgovern, Barry Foley, Martin Larsen, Jonathan White, Brendan Mchugh

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Pollution by metals has been of increasing concern for a number of decades but at present, the mechanism of metal accumulation in sentinel species is not fully understood and further studies are required for environmental risk assessment of metals in aquatic environments. The use of caging techniques has proven to be useful for assessment of water quality in coastal and estuarine environments. This study investigates the application of caging techniques for monitoring uptake of 20 elements in three marine species namely Nucella lapillus, Mytilus edulis and Crassostrea gigas. Stable isotopes were used to determine predatory effects and also used for …

Uv And Visible Light Activated Tio2 Photocatalysis Of 6-Hydroxymethyluracil, A Model Compound For The Potent Cyanotoxin Cylindrospermopsin, Cen Zhao, Miquel Pelaez, Dionysios Dionysiou, Suresh Pillai, John Byrne, Kevin O'Shea

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TiO₂ photocatalyses of 6-hydroxymethyl uracil (6-HOMU) a model compound for the potent cyanotoxin, cylindrospermopsin (CYN), were carried out employing visible and UV irradiation using different non-metal doped TiO₂ materials, nitrogen and fluorine-TiO₂ (NF-TiO₂), phosphorus and fluorine-TiO₂ (PF-TiO₂) and sulfur-TiO₂ (S-TiO₂). The model compound was readily degraded under UV TiO₂ photocatalysis with pseudo-first-order rate constants (k) of 2.1, 1.0, and 0.44 h⁻¹ for NF-TiO₂, PF-TiO₂ and S-TiO₂, respectively. Under visible light activated (VLA), NF-TiO₂ was the most active photocatalyst, PF-TiO …

Synthesis Of Orthogonally Protected Azalanthionines (Lanazanines) By Sequential Ring-Opening Of N-Substituted Aziridine 2-Carboxylates, Keith O'Brien, Keith Ó Proinsias, Fintan Kelleher

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Orthogonally protected azalanthionines (lanazanines, 4-azadiaminopimelic acids or b-aminoalaninoalanines) have been synthesised in good yields by the ring-opening of N-protected aziridine 2-carboxylates with suitably protected diaminopropanoic acids (DAPs). The required DAPs were also synthesised by ring-opening of N-protected aziridine 2-carboxylates with para-methoxybenzylamine.

A Highly Efficient Tio2-Xcx Nano-Heterojunction Photocatalyst For Visible-Light Induced Antibacterial Applications, Vinodkumar Etacheri, Michael Seery, Stephen Hinder, Georg Michlits, Suresh Pillai

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Visible-light-induced antibacterial activity of carbon-doped anatase-brookite titania nano-heterojunction photocatalysts are reported for the first time. These heterostructures were prepared using a novel low temperature (100 °C) non-hydrothermal low power microwave (300 W) assisted method. Formation of interband C 2p states was found to be responsible for the band gap narrowing of the carbon doped heterojunctions. The most active photocatalyst obtained after 60 minutes of microwave irradiation exhibits a 2-fold higher visible-light induced photocatalytic activity in contrast to the standard commercial photocatalyst Evonik-Degussa P-25. Staphylococcus aureus inactivation rate constant for carbon-doped nano-heterojunctions and the standard photocatalyst was 0.0023 and -0.0081 min …

The Bench Synthesis Of Silver Nanostructures Of Variable Size And An Introductory Analysis Of Their Optical Properties, Aoife Power, Tony Betts, John Cassidy

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A laboratory practical was designed for use by both undergraduate and second level students to demonstrate the synthesis and characterisation of tuneable silver colloids. It clearly illustrates the novel optical properties of silver nanoparticles compared to the bulk metal. The synthesis is both rapid and repeatable, and can be conducted on the laboratory bench at room temperature.

Synthesis And Modification Of Octafluoro[2.2]Paracyclophane (Parylene Af4), Craig Hicks, Brendan Duffy, Gráinne Hargaden

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Parylenes are a class of organic compounds which have gained significant attention due to their application as coatings in areas such as medical devices and electronics. This review highlights the development of synthetic pathways to Octafluoro[2.2]Paracyclophane, commonly referred to as parylene AF4. Methods which have been used to functionalise AF4 are also presented.

Sol-Gel Characteristics For Corrosion Resistance Of Anodised Aluminium, Michael Whelan, John Cassidy, Brendan Duffy

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Conventional anodising electrolytes based on sulphuric acid, oxalic acid and phosphoric acid have been used to form nanoporous layers on AA3003-H14 and sealed with silane based sol-gel sealers. It is shown that the sol-gel chemistries have varying levels of pore penetration depending on the synthesis conditions. The extent of sol-gel penetration and pore sealing is analysed by electron microscopy and energy dispersive x-ray spectroscopy. To describe the sealing phenomena observed a sol-gel penetration and sealing rating has been proposed to explain the interactions of the sol-gels with the pores of the anodised layers. The corrosion resistance of the sol-gel sealed …

Novel Microwave Assisted Synthesis Of Zns Nanomaterials, Suresh Pillai, Michael Seery, Damian Synnott, John Colreavy, Stephen Hinder

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A novel ambient pressure microwave-assisted technique is developed in which silver and indium modified ZnS is synthesised. The as prepared ZnS is characterised by X-ray diffraction, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and luminescence spectroscopy. This procedure produced crystalline materials with particle sizes below 10 nm. The synthesis technique leads to defects in the crystal which induce mid energy levels in the band gap and lead to indoor light photocatalytic activity. Increasing the amount of silver causes a phase transition from cubic blende to hexagonal phase ZnS. In a comparative study, when the ZnS cubic blende is heated in a conventional …

Nitrogen And Copper Doped Solar Light Active Tio2 Photocatalysts For Water Decontamination, Mike Fisher, Donal Keane, Pilar Fernandez-Ibanez, John Colreavy, Stephen Hinder, Kevin Mcguigan, Suresh Pillai

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A novel class of photocatalytic coating capable of degrading bacterial and chemical contaminants in the presence of visible sunlight wavelengths was produced by depositing a stable photocatalytic TiO

2 film on the internal lumen of glass bottles via a sol–gel method. This coating was prepared in either undoped form or doped with nitrogen and/or copper to produce visible light-active TiO2 films which were annealed at 600 ◦C and were characterized by Raman and X-ray photoelectron spectroscopy. The presence of doped and undoped TiO2 films was found to accelerate the degradation of methylene blue in the presence of natural sunlight, while …

The Influence Of Auxiliary Ligands On The Photophysical Characteristics Of A Series Of Ruthenium (Ii) Polypyridyl Complexes, Luke O'Neill, Laura Perdisatt, Christine O'Connor

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A series of ruthenium polypyridyl complexes were studied using UV/Vis absorption and luminescence spectroscopy as well as luminescence lifetime determination by time correlated single photon counting (TCSPC). The complexes were characterised with regard to the variation in the electronic band-gap as a result of the sequential variation of the auxiliary ligand 2,2’-bipyridine (bpy), 1,10-phenanthroline (phen) and 2,2’-biquinoline (biq) ligands while the main ligand remained constant for three different main ligand types. Luminescence yields were calculated and correlated with structural and electronic variation. It was found that both the absorption and emission characteristics could be tailored through the systematic variation of …

A Review On The Visible Light Active Titanium Dioxide Photocatalysts For Environmental Applications, Miguel Pelaez, Nicholas Nolan, Suresh Pillai, Michael Seery, Polycarpos Falaras, Athanassios G. Kontos, Patrick S.M. Dunlop, Jeremy W.J. Hamiltone, J. Anthony Byrne, Kevin O’Shea, Mohammad H. Entezari, Dionysios D. Dionysiou

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Development of visible light active (VLA) titania photocatalysts

Fujishima and Honda (1972) demonstrated the potential of titanium dioxide (TiO 2) semiconductor mate-rials to split water into hydrogen and oxygen in a photo-electrochemical cell. Their work triggered the development of semiconductor photocatalysis for a wide range of environmental and energy applica-tions. One of the most significant scientific and commercial advances to date has been the development of visible light active (VLA) TiO2 photocatalytic materials. In this review, a background on TiO2 struc-ture, properties and electronic properties in photocatalysis is presented. The development of different strategies to modify TiO2 for the utilization …

Stiefel And Grassmann Manifolds In Quantum Chemistry, Eduardo Chiumiento, Michael Melgaard

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We establish geometric properties of Stiefel and Grassmann manifolds which arise in relation to Slatertype variational spaces in many-particle Hartree-Fock theory and beyond. In particular, we prove thatthey are analytic homogeneous spaces and submanifolds of the space of bounded operators on the single-particle Hilbert space. As a by-product we obtain that they are complete Finsler manifolds. These geometric properties underpin state-of-the-art results on existence of solutions to Hartree-Fock type equations.

Preparation And Rapid Analysis Of Antibacterial Silver, Copper And Zinc Doped Sol–Gel Surfaces, Brendan Duffy, Swarna Jaiswal, Patrick Mchale

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The colonisation of clinical and industrial surfaces with microorganisms, including antibiotic-resistant strains, has promoted increased research into the development of effective antibacterial and antifouling coatings. This study describes the preparation of metal nitrate (Ag, Cu, Zn) doped methyltriethoxysilane (MTEOS) coatings and the rapid assessment of their antibacterial activity using polyproylene microtitre plates. Microtitre plate wells were coated with different volumes of liquid sol–gel and cured under various conditions. Curing parameters were analysed by thermogravimetric analysis (TGA) and visual examination. The optimum curing conditions were determined to be 50–70C using a volume of 200ul. The coated wells were challenged with Gram-positive …

Existence Of A Minimizer For The Quasi-Relativistic Kohn-Sham Model, Carlos Argáez García, Michael Melgaard

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We study the standard and extended Kohn-Sham models for quasi-relativistic N-electron Coulomb systems; that is, systems where the kinetic energy of the electrons is given by the quasi-relativistic operator (see article) . For spin-unpolarized systems in the local density approximation, we prove existence of a ground state (or minimizer) provided that the total charge Z of K nuclei is greater than N-1 and that Z is smaller than a critical charge (see article).

Characterization And Electrochromic Properties Of Poly(2,3,5,6-Tetrafluoroaniline): Progress Towards A Transparent Conducting Polymer, Lavinia Astratine, Edmond Magner, John Cassidy, Tony Betts

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Electrochromic films of poly(2,3,5,6-tetrafluoroaniline) (PTFA) were formed on ITO substrates from aqueous solutions utilising perchloric acid (HClO₄) as dopant. Electrochemical and spectroscopic characterization of PTFA films was performed in background electrolyte and in solutions with the addition of tetrahydrofuran. When the PTFA film was removed from its growth medium, a significant decrease in the faradaic current was observed. The faradaic response increased on addition of tetrahydrofuran which facilitates ion movement through the polymer matrix. PTFA films deposited on ITO substrate were orange and light orange in the oxidized and reduced forms, respectively. The films were ca. 25 nm …

Structure-Reactivity Studies Of Simple 4-Hydroxyprolinamide Organocatalysts In The Asymmetric Michael Addition Reaction Of Aldehydes To Nitroolefins, Fintan Kelleher, John Watts, Lien Luu, Vickie Mckee, Ed Carey

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A series of simple 4-hydroxyprolinamides was synthesised and they were found to act as organocatalysts for the asymmetric conjugate addition of aldehydes to nitroolefins in excellent yields (98%), with complete diastereoselectivity (99:1, syn:anti) and enantioselectivity (98% e.e. for syn). Furthermore, the use of low catalyst loadings (5 mol%) and a low aldehyde molar excess (1.5 equivalents) were achieved.

The Driving Forces Of Change In Energy-Related Co2 Emissions In Ireland: A Multi-Sectoral Decomposition From 1990 To 2007, Tadhg O'Mahony, Peng Zhou, John Sweeney

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Ireland recorded significant growth in energy-related carbon emissions from 1990 to 2007 as the country underwent rapid economic development. Using the LMDI decomposition analysis method, this paper aims to identify and analyse the driving forces of CO2 emissions in eleven final energy consuming sectors. This multi-sectoral analysis is based on four economic sectors, the residential sector and gives a detailed representation of transport in keeping with UNFCCC recommendations. Scale, structure and intensity effects are explored and substantial heterogeneity in sectoral performance is observed. Scale growth in economic and transport activity was considerable. Some improvements in energy intensity were recorded in …

Functionalized Ruthenatricarbadecaborane Via Selective Cage Iodination And Sonogashira Coupling Reactions, Ariane Perez-Gavilan, Larry Sneddon, Patrick J. Carroll

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Selective iodination of the cyclopentadienylruthenium tricarbadecaboranyl complexes 1-(η5-C5H5)–2-Ph–closo-1,2,3,4-RuC3B7H9 (1) and 1-(η5-C5(CH3)5)–2-Ph–closo-1,2,3,4-RuC3B7H8 (2) to form their mono-iodo derivatives, 1-(η5-C5H5)–2-Ph–6-I–closo-1,2,3,4-RuC3B7H9 (3) and 1-(η5-C5(CH3)5)–2-Ph–6-I–closo-1,2,3,4-RuC3B7H8(4), was achieved in 90% yields by their reactions with ICl in CH2Cl2 solutions. Also isolated in trace amounts from the reaction with 2 was the di-iodo 1-(η5-C5(CH3)5)–2-Ph–6,11-I2–closo-1,2,3,4-RuC3B7H7, (5) complex. The sonication-promoted Sonogashira coupling reaction of 3 with terminal acetylenes catalyzed by Pd(dppf)Cl2/CuI yielded the functionalized ruthenatricarbadecaboranyl complexes 1-(η5-C5H5)–2-Ph–6-(Ph-C≡C)–closo-1,2,3,4-RuC3B7H8 (6), 1-(η5-C5H5)–2-Ph–6-[CH3CH2C(O)OCH2-C≡C]–closo-1,2,3,4-RuC3B7H8 (7), …

Preparation And Characterization Of A Composite Of Gold Nanoparticles And Single-Walled Carbon Nanotubes And Its Potential For Heterogeneous Catalysis, Anne Shanahan, James Sullivan, Mary Mcnamara, Hugh Byrne

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A single-walled carbon nanotube-supported gold nanoparticle composite was prepared and characterized by X-ray diffraction, scanning transmission electron microscopy/scanning electron microscopy/transmission electron microscopy, energy-dispersive X-ray analysis, atomic absorption spectroscopy, nitrogen adsorption, Raman spectroscopy, and ultraviolet-visible spectroscopy. The Au particles were found to be crystalline, with a well-defined and narrow particle-size distribution, centered around 7 nm. The activity and selectivity of the composite for solventless aerobic oxidation of a secondary alcohol were examined, and a conversion efficiency of 95% was obtained.

Synthesis And Characterisation Of Macrocycles Containing Both Tetrazole And Pyridine Functionalities, Adrienne Fleming, Jackie Gaire, Fintan Kelleher, John Mcginley, Vickie Mckee

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The syntheses of tetra-tetrazole macrocycles containing at least one 2,6-bis(tetrazole)pyridine unit, linked by a variety of n-alkyl (n = 3, 5, 7 or 9 carbon atoms) chain lengths, are described. There has been no previous incorporation of the pyridine moiety into a tetra-tetrazolophane macrocycle. The crystal structure of one such tetra-tetrazole macrocycle has also been structurally characterised and revealed a bowl-shaped conformation.

Synthesis, Co-Polymerisation And Electrochemical Evaluation Of Novel Ferrocene-Pyrrole Derivatives, Mary Deasy, Eithne Dempsey, Geok Hong Soon, Oliver Worsfold

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New ferrocene derivatives, ((4-(1H-pyrrol-1-yl)phenoxy)carbonyl) ferrocene (4) and (6-(4-(1H-pyrrol-1-yl)phenoxy)hexyl) ferrocene (7) were synthesised, characterised and electrochemically evaluated as redox active films formed via anodic oxidation with pyrrole. Thin film studies were conducted and films formed from both compounds resulted in a stable Fe ^II/III redox couple with E^o = 0.04V and 0.36V vs. Ag/Ag⁺ for (7) and (4) respectively. Both potential sweeping and chronocoulometry were employed for film formation with the former resulting in controllable, reproducible film deposition. Growth conditions and solution concentrations were varied in the case of both compounds in order to assess …

Application Of Niobium Enriched Ormosils As Thermally Stable Coatings For Aerospace Aluminium Coatings, P.C. Rajath Varma, Mohamed Oubaha, Pradeepan Periyat, Colette Mcdonagh, Brendan Duffy

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The aim of this experimental research is to study the ability of niobium rich sol-gel coatings to withstand thermal stress, while remaining impermeable to corrosive agents for the protection of aerospace alloys. The coating material is developed via polymeric sol-gel synthesis employing 3-(trimethoxysilyl)propylmethacrylate (MAPTMS) and niobium ethoxide precursors as a source of silicon and niobium, respectively. The beneficial effect of niobium inclusion within coating was characterised spectroscopically, calorimetrically and electrochemically. The thermal cycling effects of the coating were studied using microscopic and accelerated test methods. Electrochemical tests showed that corrosion current of the material was 2 orders lower in magnitude …

Crystallisation And Phase Transition Characteristics Of Sol-Gel-Synthesized Zinc Titanates, Suresh Pillai, Michael Seery, Nicholas Nolan

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No abstract provided.