http://hdl.handle.net/10344/22 2017-11-05T08:36:11Z 2017-11-05T08:36:11Z Flynn, Grace Palaniappan, Kumaranand Sheehan, Martin Kennedy, Tadhg Ryan, Kevin M http://hdl.handle.net/10344/6229 2017-11-04T01:01:37Z 2017-01-01T00:00:00Z

Solution synthesis of lead seeded germanium nanowires and branched nanowire networks and their application as Li-ion battery anodes Flynn, Grace; Palaniappan, Kumaranand; Sheehan, Martin; Kennedy, Tadhg; Ryan, Kevin M Herein, we report the high density growth of lead seeded germanium nanowires (NWs) and their development into branched nanowire networks suitable for application as lithium ion battery anodes. The synthesis of the NWs from lead seeds occurs simultaneously in both the liquid zone (solution-liquid-solid (SLS) growth) and solvent rich vapor zone (vapor-liquid-solid (VLS) growth) of a high boiling point solvent growth system. The reaction is sufficiently versatile to allow for the growth of NWs directly from either an evaporated catalyst layer or from pre-defined nanoparticle seeds and can be extended to allowing extensive branched nanowire formation in a secondary reaction where these seeds are coated onto existing wires. The NWs are characterized using TEM, SEM, XRD and DF-STEM. Electrochemical analysis was carried out on both the single crystal Pb-Ge NWs and the branched Pb-Ge NWs to assess their suitability for use as anodes in a Li-ion battery. Differential capacity plots show both the germanium wires and the lead seeds cycle lithium and contribute to the specific capacity that is approximately 900 mAh/ g for the single crystal wires, rising to approximately 1100 mAh/ g for the branched nanowire networks. peer-reviewed; The full text of this article will not be available in ULIR until the embargo expires on the 1/6/2018

2017-01-01T00:00:00Z Melin, Frederic Schoepp-Cothenet, Barbara Abdulkarim, Saleh Noor, Mohamed R Soulimane, Tewfik Hellwig, Petra http://hdl.handle.net/10344/6211 2017-11-01T01:02:24Z 2017-01-01T00:00:00Z

Electrochemical study of an electron shuttle diheme protein: the cytochrome c550 from T. thermophilus Melin, Frederic; Schoepp-Cothenet, Barbara; Abdulkarim, Saleh; Noor, Mohamed R; Soulimane, Tewfik; Hellwig, Petra Cytochrome c550 , a diheme protein from the thermophilic bacterium Thermus thermophilus, is involved in an alternative respiration pathway allowing the detoxification of sulfite ions. It transfers the two electrons released from the oxidation of sulfite in a sulfite:cytochrome c oxidoreductase (SOR) enzyme to heme/copper oxidases via the monoheme cytochrome c552. It consists of two conformationally independent and structurally different domains (the C- and N-terminal) connected by a flexible linker. Both domains harbor one heme moiety. We report here the redox properties of the full-length protein and the individual C- and N-terminal fragments. We show by UV/Vis and EPR potentiometric titrations that the two fragments exhibit very similar potentials, despite their different environments. In the full-length protein, however, the N-terminal heme is easier to reduce than the C-terminal one, due to cooperative interactions. This finding is consistent with the kinetic measurements which showed that the N-terminal domain only accepts electrons from the SOR. Cytochrome c552 is able to interact with its partners both through electrostatic and hydrophobic interactions as could be shown by measuring efficient electron transfer at gold electrodes modified with charged and hydrophobic groups, respectively. The coupling of electrochemistry with infrared spectroscopy allowed us to monitor the conformational changes induced by electron transfer to each heme separately and to both simultaneously. peer-reviewed; The full text of this article will not be available in ULIR until the embargo expires on the 8/5/2019

2017-01-01T00:00:00Z Armstrong, Gordon Birkett, David http://hdl.handle.net/10344/6201 2017-10-26T00:02:07Z 2009-01-01T00:00:00Z

In focus: advances in epoxy chemistry Armstrong, Gordon; Birkett, David Advances in electronics, in energy efficient transport technology and in energy generation from renewable sources require parallel advances in polymer chemistry. A key chemistry in all these areas is that of the epoxy group and there are currently exciting developments in this field. Advanced epoxy composites contribute to the increasing use of plastics in next-generation aircraft such as the Airbus A380 and the Boeing 787 Dreamliner. Toughened epoxy adhesives allow cars to be lighter and yet more crash resistant. Other epoxies hold together the blades of wind turbines, or the electronics in your phone, laptop or i-Pod. peer-reviewed

2009-01-01T00:00:00Z Armstrong, Gordon Buggy, Martin http://hdl.handle.net/10344/6200 2017-10-26T00:02:07Z 2002-01-01T00:00:00Z

Thermal stability of some self-assembling hydrogen-bonded polymers and related model complexes Armstrong, Gordon; Buggy, Martin The thermal stability of polymers is of fundamental importance both in processing and in many applications, eg, injection moulding, hot melts. As part of an investigation to determine the suitability of supramolecular polymers for novel applications in materials science, the thermal behaviour of two model compounds representing the principal classes of supramolecular polymer has been studied in some detail. p-Methoxybenzoic acid was complexed with 1,2-di(4-pyridyl) ethylene in 2:1 ratio as a model compound representing liquid-crystal association chain supramolecular polymers. It is proposed that the model compound degrades as a single species obeying first-order kinetics; the activation energy (E-act) of the degradation process was calculated to be 127kJ mol(-1). A model ureido-pyrimidinone dimer degraded in two steps, also following first order kinetics, with E-act = 71.5kJ mol(-1). The dimer was unaffected by annealing, suggesting that related polymers may be used at elevated temperatures. Polymer analogues of both model compounds were synthesized and their thermal behaviour was found to parallel that of the models. In light of these results, the implications for processing both supramolecular polymers are also considered. (C) 2002 Society of Chemical Industry. peer-reviewed

2002-01-01T00:00:00Z