Imperial College London

ProfessorMaryRyan

Faculty of EngineeringDepartment of Materials

Vice-Dean (Research), Faculty of Engineering
 
 
 
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Contact

 

+44 (0)20 7594 6755m.p.ryan

 
 
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Location

 

B338Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

219 results found

Woolley RJ, Ryan MP, Skinner SJ, 2013, In Situ Measurements on Solid Oxide Fuel Cell Cathodes - Simultaneous X-Ray Absorption and AC Impedance Spectroscopy on Symmetrical Cells, FUEL CELLS, Vol: 13, Pages: 1080-1087, ISSN: 1615-6846

Journal article

Zhang J, Nazarenko Y, Zhang L, Calderon L, Lee K-B, Garfunkel E, Schwander S, Tetley TD, Chung KF, Porter AE, Ryan M, Kipen H, Lioy PJ, Mainelis Get al., 2013, Impacts of a Nanosized Ceria Additive on Diesel Engine Emissions of Particulate and Gaseous Pollutants, ENVIRONMENTAL SCIENCE & TECHNOLOGY, Vol: 47, Pages: 13077-13085, ISSN: 0013-936X

Journal article

Leo BF, Chen S, Kyo Y, Herpoldt KL, Terrill NJ, Dunlop IE, McPhail D, Shaffer MS, Schwander S, Gow A, Zhang J, Chung KF, Tetley T, Porter AE, Ryan MPet al., 2013, The Stability of Silver Nanoparticles in a Model of Pulmonary Surfactant., Environ Sci Technol, Vol: 47, Pages: 11232-11240

The growing use of silver nanoparticles (AgNPs) in consumer products has raised concerns about their potential impact on the environment and human health. Whether AgNPs dissolve and release Ag+ ions, or coarsen to form large aggregates, is critical in determining their potential toxicity. In this work, the stability of AgNPs in dipalmitoylphosphatidylcholine (DPPC), the major component of pulmonary surfactant, was investigated as a function of pH. Spherical, citrate-capped AgNPs with average diameters of 14 ± 1.6 nm (n=200) were prepared by a chemical bath reduction. The kinetics of Ag+ ion release was strongly pH-dependent. After 14 days of incubation in sodium perchlorate (NaClO4) or perchloric acid (HClO4) solutions, the total fraction of AgNPs dissolved varied from ~10 % at pH 3, to ~2 % at pH 5, with negligible dissolution at pH 7. A decrease in pH from 7 to 3 also promoted particle aggregation and coarsening. DPPC (100 mg.L-1) delayed the release of Ag+ ions, but did not significantly alter the total amount of Ag+ released after two weeks. In addition, DPPC improved the dispersion of the AgNPs and inhibited aggregation and coarsening. TEM images revealed that the AgNPs were coated with a DPPC layer serving as a semi-permeable layer. Hence, lung lining fluid, particularly DPPC, can modify the aggregation state and kinetics of Ag+ ion release of inhaled AgNPs in the lung. These observations have important implications for predicting the potential reactivity of AgNPs in the lung and the environment.

Journal article

Pishbin F, Mourino V, Gilchrist JB, McComb DW, Kreppel S, Salih V, Ryan MP, Boccaccini ARet al., 2013, Single-step electrochemical deposition of antimicrobial orthopaedic coatings based on a bioactive glass/chitosan/nano-silver composite system, ACTA BIOMATERIALIA, Vol: 9, Pages: 7469-7479, ISSN: 1742-7061

Journal article

Hatch SM, Briscoe J, Sapelkin A, Gillin WP, Gilchrist JB, Ryan MP, Heutz S, Dunn Set al., 2013, Influence of anneal atmosphere on ZnO-nanorod photoluminescent and morphological properties with self-powered photodetector performance, JOURNAL OF APPLIED PHYSICS, Vol: 113, ISSN: 0021-8979

Journal article

Xie F, Pang J, Centeno A, Ryan M, Riley J, Alford Net al., 2013, Nanoscale control of Ag nanostructures for plasmonic fluorescence enhancement of near-infrared dyes, Nano Research, Vol: 6, Pages: 495-510, ISSN: 1998-0124

Potential utilization of proteins for early detection and diagnosis of various diseases has drawn considerable interest in the development of protein-based detection techniques. Metal induced fluorescence enhancement offers the possibility of increasing the sensitivity of protein detection in clinical applications. We report the use of tunable plasmonic silver nanostructures for the fluorescence enhancement of a near-infrared (NIR) dye (Alexa Fluor 790). Extensive fluorescence enhancement of ∼2 orders of magnitude is obtained by the nanoscale control of the Ag nanostructure dimensions and interparticle distance. These Ag nanostructures also enhanced fluorescence from a dye with very high quantum yield (7.8 fold for Alexa Fluor 488, quantum efficiency (Qy) = 0.92). A combination of greatly enhanced excitation and an increased radiative decay rate, leading to an associated enhancement of the quantum efficiency leads to the large enhancement. These results show the potential of Ag nanostructures as metal induced fluorescence enhancement (MIFE) substrates for dyes in the NIR “biological window” as well as the visible region. Ag nanostructured arrays fabricated by colloidal lithography thus show great potential for NIR dye-based biosensing applications.

Journal article

Downing JM, Ryan MP, McLachlan MA, 2013, Hydrothermal growth of ZnO nanorods: The role of KCl in controlling rod morphology, Thin Solid Films

The role of potassium chloride (KCl) in controlling ZnO nanorod morphology of large area thin films prepared by hydrothermal growth has been extensively investigated. The influence of KCl and growth time on the orientation, morphology and microstructure of the nanorod arrays has been studied with systematic changes in the length, width, density and termination of the nanorods observed. Such changes are attributed to stabilization of the high-energy (002) nanorod surface by the KCl. At low KCl concentrations (< 100 mM) c-axis growth i.e. perpendicular to the polar surface, dominates, leading to nanorods with increased length over the control sample (0 mM KCl). At higher concentrations (> 100 mM) stabilization of the high-energy surface by KCl occurs and planar (002) facets are observed accompanied by increased lateral (100) growth, at the highest KCl concentrations near coalesced (002) terminated rods are observed. Additionally we correlate the KCl concentration with the uniformity of the nanorod arrays; a decrease in polydispersity with increased KCl concentration is observed. The vertical alignment of nanorod arrays was studied using X-ray diffraction, it was found that this parameter increases as growth time and KCl concentration are increased. We propose that the increase in vertical alignment is a result of nanorod–nanorod interactions during the early stages of growth.

Journal article

Moorhouse BS, Reddyhoff T, Ward-Close M, Ryan MP, Shollock BAet al., 2013, Formation of wear resistant coatings on Ti-6Al-4V by calciothermic reduction, SURFACE & COATINGS TECHNOLOGY, Vol: 221, Pages: 214-221, ISSN: 0257-8972

Journal article

Xie F, Centeno A, Zou B, Ryan MP, Riley DJ, Alford NMet al., 2013, Tunable synthesis of ordered Zinc Oxide nanoflower-like arrays, JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 395, Pages: 85-90, ISSN: 0021-9797

Journal article

Chen S, Goode AE, Sweeney S, Theodorou IG, Thorley AJ, Ruenraroengsak P, Chang Y, Gow A, Schwander S, Skepper J, Zhang JJ, Shaffer MS, Chung KF, Tetley TD, Ryan MP, Porter AEet al., 2013, Sulfidation of silver nanowires inside human alveolar epithelial cells: a potential detoxification mechanism, NANOSCALE, Vol: 5, Pages: 9839-9847, ISSN: 2040-3364

Journal article

Pang JS, Xie F, Centeno A, Petrov PK, Ryan MP, Alford Net al., 2012, Optical absorption of metal nanoparticle arrays

A study into the enhanced optical absorption due to metal nanoparticle arrays fabricated by nanosphere lithography. Prediction and measurement has been undertaken. Implementation to improve the efficiency of PV solar cells is discussed. © 2012 OSA.

Conference paper

Pang JS, Xie F, Centeno A, Petrov PK, Ryan MP, Alford Net al., 2012, Optical absorption of metal nanoparticle arrays

A study into the enhanced optical absorption due to metal nanoparticle arrays fabricated by nanosphere lithography. Prediction and measurement has been undertaken. Implementation to improve the efficiency of PV solar cells is discussed. © 2012 OSA.

Conference paper

Pang JS, Xie F, Centeno A, Petrov PK, Ryan MP, Alford Net al., 2012, Optical absorption of metal nanoparticle arrays

A study into the enhanced optical absorption due to metal nanoparticle arrays fabricated by nanosphere lithography. Prediction and measurement has been undertaken. Implementation to improve the efficiency of PV solar cells is discussed. © 2012 OSA.

Conference paper

Pang JS, Xie F, Centeno A, Petrov PK, Ryan MP, Alford Net al., 2012, Optical absorption of metal nanoparticle arrays

A study into the enhanced optical absorption due to metal nanoparticle arrays fabricated by nanosphere lithography. Prediction and measurement has been undertaken. Implementation to improve the efficiency of PV solar cells is discussed. © 2012 OSA.

Conference paper

Hannemann U, Lyubina J, Ryan MP, Alford NM, Cohen LFet al., 2012, Thermopower of LaFe13-xSix alloys, EPL, Vol: 100, ISSN: 0295-5075

Journal article

Pang JS, Xie F, Centeno A, Petrov PK, Ryan MP, Alford Net al., 2012, Optical absorption of metal nanoparticle arrays

© 2012 OSA. A study into the enhanced optical absorption due to metal nanoparticle arrays fabricated by nanosphere lithography. Prediction and measurement has been undertaken. Implementation to improve the efficiency of PV solar cells is discussed.

Conference paper

Lyubina J, Hannemann U, Cohen LF, Ryan MPet al., 2012, Novel La(Fe,Si)(13)/Cu Composites for Magnetic Cooling, ADVANCED ENERGY MATERIALS, Vol: 2, Pages: 1323-1327, ISSN: 1614-6832

Journal article

Cruickshank AC, Dotzler CJ, Din S, Heutz S, Toney MF, Ryan MPet al., 2012, The Crystalline Structure of Copper Phthalocyanine Films on ZnO(1(1)over-bar00), JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 134, Pages: 14302-14305, ISSN: 0002-7863

Journal article

Dunlop IE, Ryan MP, Weaver JVM, 2012, One-step preparation of bioapplicable nanoparticles using branched copolymer nanoreactors, 244th National Fall Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Corni I, Chater RJ, Boccaccini AR, Ryan MPet al., 2012, Electro co-deposition of Ni-Al2O3 composite coatings, JOURNAL OF MATERIALS SCIENCE, Vol: 47, Pages: 5361-5373, ISSN: 0022-2461

Journal article

Lyubina J, Hannemann U, Ryan MP, Cohen LFet al., 2012, Electrolytic Hydriding of LaFe13-xSix Alloys for Energy Efficient Magnetic Cooling, ADVANCED MATERIALS, Vol: 24, Pages: 2042-2046, ISSN: 0935-9648

Journal article

Ingham B, Gaston N, Fahy K, Chin XY, Dotzler CJ, Rees E, Haslam G, Barber ZH, Burstein GT, Ryan MPet al., 2012, Extended X-ray Absorption Fine Structure and X-ray Diffraction Examination of Sputtered Nickel Carbon Binary Thin Films for Fuel Cell Applications, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 116, Pages: 6159-6165, ISSN: 1932-7447

Journal article

Franklin JB, Downing JM, Giuliani F, Ryan MP, McLachlan MAet al., 2012, Building on Soft Foundations – New Possibilities for Controlling Hybrid Photovoltaic Architectures, Advanced Energy Materials

Here we outline a methodology for the deposition of a highly crystalline transparent conductive metal oxide (ZnO) onto a functionalised organic thin film poly (3-hexylthiophene, P3HT) without degradation of the microstructural, optical or electronic properties of the organic layer. To confirm the absence of damage we have assembled a simple bilayer photovoltaic (PV) device. The processing methodology has enabled us to demonstrate hybrid photovoltaic (h-PV) device formation in the conventional architecture for the first time. The compatibility of this novel low temperature processing route with π-conjugated molecular materials has tremendous potential for applications including electron accepting layers and optical spacers in organic PVs and light emitting diodes, as transparent electrodes and all future devices reliant on flexible substrates.

Journal article

Goode AE, Perkins JM, Sandison A, Karunakaran C, Cheng H, Wall D, Skinner JA, Hart AJ, Porter AE, McComb DW, Ryan MPet al., 2012, Chemical speciation of nanoparticles surrounding metal-on-metal hips, CHEMICAL COMMUNICATIONS, Vol: 48, Pages: 8335-8337, ISSN: 1359-7345

Journal article

Pang JS, Xie F, Centeno A, Petrov PK, Ryan MP, Alford Net al., 2012, Optical absorption of metal nanoparticle arrays

A study into the enhanced optical absorption due to metal nanoparticle arrays fabricated by nanosphere lithography. Prediction and measurement has been undertaken. Implementation to improve the efficiency of PV solar cells is discussed. © 2012 OSA.

Conference paper

Moorhouse BS, Ward-Close M, Ryan MP, Shollock BAet al., 2012, Calciothermic Reduction of Ti-6Al-4V, 12th World Conference on Titanium (Ti-2011), Publisher: SCIENCE PRESS BEIJING, Pages: 1662-1665

Conference paper

Aili D, Gryko P, Sepulveda B, Dick JAG, Kirby N, Heenan R, Baltzer L, Liedberg B, Ryan MP, Stevens MMet al., 2011, Polypeptide Folding-Mediated Tuning of the Optical and Structural Properties of Gold Nanoparticle Assemblies, NANO LETTERS, Vol: 11, Pages: 5564-5573, ISSN: 1530-6984

Journal article

Dotzler CJ, Ingham B, Illy BN, Wallwork K, Ryan MP, Toney MFet al., 2011, In Situ Observation of Strain Development and Porosity Evolution in Nanoporous Gold Foils, ADVANCED FUNCTIONAL MATERIALS, Vol: 21, Pages: 3938-3946, ISSN: 1616-301X

Journal article

Pishbin F, Simchi A, Ryan MP, Boccaccini ARet al., 2011, Electrophoretic deposition of chitosan/45S5 Bioglass (R) composite coatings for orthopaedic applications, SURFACE & COATINGS TECHNOLOGY, Vol: 205, Pages: 5260-5268, ISSN: 0257-8972

Journal article

Illy BN, Cruickshank AC, Da Campo R, Schumann S, Jones TS, Heutz SEM, McLachlan MA, McComb DW, Riley DJ, Ryan MPet al., 2011, Electrodeposition of ultrathin ZnO buffer layers with controllable orientation for photovoltaic applications, ISSN: 0065-7727

ZnO is one of the most promising materials for applications in nanotechnology due to its large band gap and high electron mobility. A large amount of work has focused on the study of nanostructured ZnO. However, two dimensional transparent compact layers are also of great interest as transparent conductive oxides in optoelectronic devices. Compact ZnO layers are usually deposited by methods which are generally costly thus significantly limiting their potential application. Electrodeposition is a low cost alternative, offering a high degree of control on the characteristics. In this work the effects of the deposition parameters on the film characteristics have been studied in order to fabricate the thinnest electrodeposited films ever reported and to tune the crystallographic orientation. Incorporation of the layer into an organic ZnO/P3HT:PCBM solar cell is used to demonstrate how a careful control of the orientation can dramatically improve the photovoltaic device efficiency.

Conference paper

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