Imperial College London

Prof Milo Shaffer

Faculty of Natural SciencesDepartment of Chemistry

Professor of Materials Chemistry
 
 
 
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Contact

 

+44 (0)20 7594 5825m.shaffer Website

 
 
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Assistant

 

Mr John Murrell +44 (0)20 7594 2845

 
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Location

 

M221Royal College of ScienceSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

278 results found

Anthony DB, Shaffer MSP, 2016, Process for producing carbon-nanotube grafted substrate, WO 2016009207 A1

The present invention relates to a process for producing a carbon nanotube-grafted substrate, the process comprising: providing a substrate having catalytic material deposited thereon; and synthesising carbon nanotubes on the substrate by a chemical vapour deposition process in a reaction chamber; characterised in that the process comprises providing a counter electrode, applying a potential difference to the substrate in relation to the counter electrode and maintaining the potential difference of the substrate in relation to the counter electrode during the chemical vapour deposition process.

Patent

Clancy ARJ, Bayazit M, shaffer M, Hodge S, Chen S, Menzelet al., 2015, Carbon nanotube anions for the preparation of gold nanoparticle-nanocarbon hybrids, Chemical Communications, Vol: 52, Pages: 1934-1937, ISSN: 1364-548X

Gold nanoparticles (AuNPs) can be evenly deposited on singlewalledcarbon nanotubes (SWCNTs) via the reduction of the highlystable complex, chloro(triphenylphosphine) gold(I), with SWCNTanions (‘nanotubides’). This methodology highlights the unusualchemistry of nanotubides and provides a blueprint for thegeneration of many other hybrid nanomaterials.

Journal article

De Luca F, Menzel R, Blaker JJ, Birkbeck J, Bismarck A, Shaffer MSPet al., 2015, Nacre-nanomimetics: Strong, Stiff, and Plastic, ACS APPLIED MATERIALS & INTERFACES, Vol: 7, Pages: 26783-26791, ISSN: 1944-8244

Journal article

Iruretagoyena D, Huang X, Shaffer MSP, Chadwick Det al., 2015, Influence of Alkali Metals (Na, K, and Cs) on CO2 Adsorption by Layered Double Oxides Supported on Graphene Oxide, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, Vol: 54, Pages: 11610-11618, ISSN: 0888-5885

Journal article

Yau H, Shaffer MSP, 2015, Sonochemical Degradation of N-Methylpyrrolidone and Its Influence on Single Walled Carbon Nanotube Dispersion, Chemical Communications, Vol: 51, Pages: 16621-16624, ISSN: 1364-548X

Sonicating pure N-methyl pyrrolidone (NMP) rapidly produces contaminating organic nanoparticles, at increasing concentration with time, as investigated by AFM, as well as UV-vis, IR and NMR spectroscopies. The contamination issue affects nanotube, and likely other nanomaterial, dispersions processed by sonication in organic solvents.

Journal article

Javaid A, Ho KKC, Bismarck A, Steinke JHG, Shaffer MSP, Greenhalgh ESet al., 2015, Carbon fibre-reinforced poly(ethylene glycol) diglycidylether based multifunctional structural supercapacitor composites for electrical energy storage applications, Journal of Composite Materials, Vol: 50, Pages: 2155-2163, ISSN: 1530-793X

Journal article

Goode AE, Gonzalez Carter DA, Motskin M, Pienaar IS, Chen S, Hu S, Ruenraroengsak P, Ryan M, Shaffer MSP, Dexter DT, Porter AEet al., 2015, High resolution and dynamic imaging of biopersistence and bioreactivity of extra and intracellular MWNTs exposed to microglial cells, Biomaterials, Vol: 70, Pages: 57-70, ISSN: 1878-5905

Multi-walled carbon nanotubes (MWNTs) are increasingly being developed both as neuro-therapeutic drug delivery systems to the brain and as neural scaffolds to drive tissue regeneration across lesion sites. MWNTs with different degrees of acid oxidation may have different bioreactivities and propensities to aggregate in the extracellular environment, and both individualised and aggregated MWNTs may be expected to be found in the brain. Before practical application, it is vital to understand how both aggregates and individual MWNTs will interact with local phagocytic immune cells, the microglia, and ultimately to determine their biopersistence in the brain. The processing of extra- and intracellular MWNTs (both pristine and when acid oxidised) by microglia was characterised across multiple length scales by correlating a range of dynamic, quantitative and multi-scale techniques, including: UV-vis spectroscopy, light microscopy, focussed ion beam scanning electron microscopy and transmission electron microscopy. Dynamic, live cell imaging revealed the ability of microglia to break apart and internalise micron-sized extracellular agglomerates of acid oxidised MWNT, but not pristine MWNTs. The total amount of MWNTs internalised by, or strongly bound to, microglia was quantified as a function of time. Neither the significant uptake of oxidised MWNTs, nor the incomplete uptake of pristine MWNTs affected microglial viability, pro-inflammatory cytokine release or nitric oxide production. However, after 24 hrs exposure to pristine MWNTs, a significant increase in the production of reactive oxygen species was observed. Small aggregates and individualised oxidised MWNTs were present in the cytoplasm and vesicles, including within multilaminar bodies, after 72 hours. Some evidence of morphological damage to oxidised MWNT structure was observed including highly disordered graphitic structures, suggesting possible biodegradation. This work demonstrates the utility of dynamic, quant

Journal article

Clancy AJ, Melbourne J, Shaffer MSP, 2015, A one-step route to solubilised, purified or functionalised single-walled carbon nanotubes, Journal of Materials Chemistry A, Vol: 3, Pages: 16708-16715, ISSN: 2050-7496

Reductive dissolution is a promising processing route for single walled carbon nanotubes (SWCNTs) thatavoids the damage caused by ultrasonication and aggressive oxidation whilst simultaneously allowingaccess to a wealth of SWCNT functionalisation reactions. Here, reductive dissolution has been simplifiedto a single one-pot reaction through the use of sodium naphthalide in dimethylacetamide allowingdirect synthesis of SWCNT Na+ solutions. Gram quantities of SWCNTs can be dissolved at concentrationsover 2 mg mL 1. These reduced SWCNT solutions can easily be functionalised through the addition ofalkyl halides; reducing steric bulk of the grafting moiety and increasing polarisability of the leaving groupincreases the extent of functionalisation. An optimised absolute sodium concentration of 25 mM isshown to be more important than carbon to metal ratio in determining the maximum degree offunctionalisation. This novel dissolution system can be modified for use as a non-destructive purificationroute for raw SWCNT powder by adjusting the degree of charging to dissolve carbonaceous impurities,catalyst particles and defective material, before processing the remaining SWCNTs.

Journal article

Iruretagoyena D, Shaffer MSP, Chadwick D, 2015, Layered Double Oxides Supported on Graphene Oxide for CO2 Adsorption: Effect of Support and Residual Sodium, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, Vol: 54, Pages: 6781-6792, ISSN: 0888-5885

Journal article

Theodorou IG, Botelho D, Schwander S, Zhang J, Chung KF, Tetley TD, Shaffer MSP, Gow A, Ryan MP, Porter AEet al., 2015, Static and Dynamic Microscopy of the Chemical Stability and Aggregation State of Silver Nanowires in Components of Murine Pulmonary Surfactant, ENVIRONMENTAL SCIENCE & TECHNOLOGY, Vol: 49, Pages: 8048-8056, ISSN: 0013-936X

Journal article

Sweeney S, Theodorou IG, Zambianchi M, Chen S, Gow A, Schwander S, Zhang JJ, Chung KF, Shaffer MS, Ryan MP, Porter AE, Tetley TDet al., 2015, Silver nanowire interactions with primary human alveolar type-II epithelial cell secretions: contrasting bioreactivity with human alveolar type-I and type-II epithelial cells., Nanoscale, Vol: 7, Pages: 10398-10409, ISSN: 2040-3372

Inhaled nanoparticles have a high deposition rate in the alveolar units of the deep lung. The alveolar epithelium is composed of type-I and type-II epithelial cells (ATI and ATII respectively) and is bathed in pulmonary surfactant. The effect of native human ATII cell secretions on nanoparticle toxicity is not known. We investigated the cellular uptake and toxicity of silver nanowires (AgNWs; 70 nm diameter, 1.5 μm length) with human ATI-like cells (TT1), in the absence or presence of Curosurf® (a natural porcine pulmonary surfactant with a low amount of protein) or harvested primary human ATII cell secretions (HAS; containing both the complete lipid as well as the full protein complement of human pulmonary surfactant i.e. SP-A, SP-B, SP-C and SP-D). We hypothesised that Curosurf® or HAS would confer improved protection for TT1 cells, limiting the toxicity of AgNWs. In agreement with our hypothesis, HAS reduced the inflammatory and reactive oxygen species (ROS)-generating potential of AgNWs with exposed TT1 cells. For example, IL-8 release and ROS generation was reduced by 38% and 29%, respectively, resulting in similar levels to that of the non-treated controls. However in contrast to our hypothesis, Curosurf® had no effect. We found a significant reduction in AgNW uptake by TT1 cells in the presence of HAS but not Curosurf. Furthermore, we show that the SP-A and SP-D are likely to be involved in this process as they were found to be specifically bound to the AgNWs. While ATI cells appear to be protected by HAS, evidence suggested that ATII cells, despite no uptake, were vulnerable to AgNW exposure (indicated by increased IL-8 release and ROS generation and decreased intracellular SP-A levels one day post-exposure). This study provides unique findings that may be important for the study of lung epithelial-endothelial translocation of nanoparticles in general and associated toxicity within the alveolar unit.

Journal article

Melbourne J, Clancy A, Seiffert J, Skepper J, Tetley TD, Shaffer MS, Porter Aet al., 2015, An investigation of the carbon nanotube - Lipid interface and its impact upon pulmonary surfactant lipid function., Biomaterials, Vol: 55, Pages: 24-32, ISSN: 1878-5905

Multiwalled carbon nanotubes (MWCNTs) are now synthesized on a large scale, increasing the risk of occupational inhalation. However, little is known of the MWCNT-pulmonary surfactant (PS) interface and its effect on PS functionality. The Langmuir-Blodgett trough was used to evaluate the impact of MWCNTs on fundamental properties of PS lipids which influence PS function, i.e. compression resistance and maximum obtainable pressure. Changes were found to be MWCNT length-dependent. 'Short' MWCNTs (1.1 μm, SD = 0.61) penetrated the lipid film, reducing the maximum interfacial film pressure by 10 mN/m (14%) in dipalmitoylphosphatidylcholine (DPPC) and PS, at an interfacial MWCNT-PS lipid mass ratio range of 50:1 to 1:1. 'Long' commercial MWCNTs (2.1 μm, SD = 1.2) caused compression resistance at the same mass loadings. 'Very long' MWCNTs (35 μm, SD = 19) sequestered DPPC and were squeezed out of the DPPC film. High resolution transmission electron microscopy revealed that all MWCNT morphologies formed DPPC coronas with ordered arrangements. These results provide insight into how nanoparticle aspect ratio affects the interaction mechanisms with PS, in its near-native state at the air-water interface.

Journal article

Brown NJ, Garcia-Trenco A, Weiner J, White ER, Allinson M, Chen Y, Wells PP, Gibson EK, Hellgardt K, Shaffer MSP, Williams CKet al., 2015, From Organometallic Zinc and Copper Complexes to Highly Active Colloidal Catalysts for the Conversion of CO2 to Methanol, ACS Catalysis, Vol: 5, Pages: 2895-2902, ISSN: 2155-5435

A series of zinc oxide and copper(0) colloidal nanocatalysts, produced by a one-pot synthesis, are shown to catalyze the hydrogenation of carbon dioxide to methanol. The catalysts are produced by the reaction between diethyl zinc and bis(carboxylato/phosphinato)copper(II) precursors. The reaction leads to the formation of a precatalyst solution, characterized using various spectroscopic (NMR, UV–vis spectroscopy) and X-ray diffraction/absorption (powder XRD, EXAFS, XANES) techniques. The combined characterization methods indicate that the precatalyst solution contains copper(0) nanoparticles and a mixture of diethyl zinc and an ethyl zinc stearate cluster compound [Et4Zn5(stearate)6]. The catalysts are applied, at 523 K with a 50 bar total pressure of a 3:1 mixture of H2/CO2, in the solution phase, quasi-homogeneous, hydrogenation of carbon dioxide, and they show high activities (>55 mmol/gZnOCu/h of methanol). The postreaction catalyst solution is characterized using a range of spectroscopies, X-ray diffraction techniques, and transmission electron microscopy (TEM). These analyses show the formation of a mixture of zinc oxide nanoparticles, of size 2–7 nm and small copper nanoparticles. The catalyst composition can be easily adjusted, and the influence of the relative loadings of ZnO/Cu, the precursor complexes and the total catalyst concentration on the catalytic activity are all investigated. The optimum system, comprising a 55:45 loading of ZnO/Cu, shows equivalent activity to a commercial, activated methanol synthesis catalyst. These findings indicate that using diethyl zinc to reduce copper precursors in situ leads to catalysts with excellent activities for the production of methanol from carbon dioxide.

Journal article

Marchetti M, Shaffer MSP, Zambianchi M, Chen S, Superti F, Schwander S, Gow A, Zhang JJ, Chung KF, Ryan MP, Porter AE, Tetley TDet al., 2015, Adsorption of surfactant protein D from human respiratory secretions by carbon nanotubes and polystyrene nanoparticles depends on nanomaterial surface modification and size, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, Vol: 370, ISSN: 0962-8436

Journal article

Chen S, Goode AE, Skepper JN, Thorley AJ, Seiffert JM, Chung KF, Tetley TD, Shaffer MSP, Ryan MP, Porter AEet al., 2015, Avoiding artefacts during electron microscopy of silver nanomaterials exposed to biological environments, Journal of Microscopy, Vol: 261, Pages: 157-166, ISSN: 1365-2818

Electron microscopy has been applied widely to study the interaction of nanomaterials with proteins, cells and tissues at nanometre scale. Biological material is most commonly embedded in thermoset resins to make it compatible with the high vacuum in the electron microscope. Room temperature sample preparation protocols developed over decades provide contrast by staining cell organelles, and aim to preserve the native cell structure. However, the effect of these complex protocols on the nanomaterials in the system is seldom considered. Any artefacts generated during sample preparation may ultimately interfere with the accurate prediction of the stability and reactivity of the nanomaterials. As a case study, we review steps in the room temperature preparation of cells exposed to silver nanomaterials (AgNMs) for transmission electron microscopy imaging and analysis. In particular, embedding and staining protocols, which can alter the physicochemical properties of AgNMs and introduce artefacts thereby leading to a misinterpretation of silver bioreactivity, are scrutinized. Recommendations are given for the application of cryogenic sample preparation protocols, which simultaneously fix both particles and diffusible ions. By being aware of the advantages and limitations of different sample preparation methods, compromises or selection of different correlative techniques can be made to draw more accurate conclusions about the data. Lay description: With increasing commercialization of silver nanomaterials (AgNMs) comes a concomitant need to understand occupational health, public safety and environmental implications of these materials. Nanoscale studies of the complex bio-nano interface lie at the heart of technical challenges. Despite numerous reports, there is no consensus regarding biological mechanisms enacted by AgNMs. Powerful new electron microscopy techniques can be used to visualize the interaction of the AgNMs with tissues. However, it is extremely difficult to

Journal article

Menzel R, Barg S, Miranda M, Anthony DB, Bawaked SM, Mokhtar M, Al-Thabaiti SA, Basahel SN, Saiz E, Shaffer MSPet al., 2015, Joule Heating Characteristics of Emulsion-Templated Graphene Aerogels, ADVANCED FUNCTIONAL MATERIALS, Vol: 25, Pages: 28-35, ISSN: 1616-301X

Journal article

Noimark S, Weiner J, Noor N, Allan E, Williams CK, Shaffer MSP, Parkin IPet al., 2015, Dual-Mechanism Antimicrobial Polymer-ZnO Nanoparticle and Crystal Violet-Encapsulated Silicone, Advanced Functional Materials, Vol: 25, Pages: 1367-1373, ISSN: 1616-3028

Journal article

Yau HC, Bayazit MK, Gaffney PRJ, Livingston AG, Steinke JHG, Shaffer MSPet al., 2015, Synthesis and characterization of branched fullerene-terminated poly(ethylene glycol)s, POLYMER CHEMISTRY, Vol: 6, Pages: 1056-1065, ISSN: 1759-9954

Journal article

Gogotsi Y, McCreery R, Lyth SM, Dryfe R, Foord J, Velicky M, Macpherson J, Duca M, Holt K, Alvarez-Guerra M, Kurig H, Sharma S, Unwin PR, Chen GZ, Shaffer M, Alaje T, Hamers R, Newton M, Ash PA, Stevenson K, Waldvogel S, Hu J, Gueell A, Quinson Jet al., 2014, Carbon electrode interfaces for synthesis, sensing and electrocatalysis: general discussion, FARADAY DISCUSSIONS, Vol: 172, Pages: 497-520, ISSN: 1359-6640

Journal article

Shirshova N, Bismarck A, Greenhalgh ES, Johansson P, Kalinka G, Marczewski MJ, Shaffer MSP, Wienrich Met al., 2014, Composition as a Means To Control Morphology and Properties of Epoxy Based Dual-Phase Structural Electrolytes, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 118, Pages: 28377-28387, ISSN: 1932-7447

Journal article

Hu S, Chen S, Menzel R, Goode AD, Ryan MP, Porter AE, Shaffer MSPet al., 2014, Aqueous dispersions of oligomer-grafted carbon nanomaterials with controlled surface charge and minimal framework damage, FARADAY DISCUSSIONS, Vol: 173, Pages: 273-285, ISSN: 1359-6640

Journal article

Greenhalgh ES, Ankersen J, Asp LE, Bismarck A, Fontana QPV, Houlle M, Kalinka G, Kucernak A, Mistry M, Nguyen S, Qian H, Shaffer MSP, Shirshova N, Steinke JHG, Wienrich Met al., 2014, Mechanical, electrical and microstructural characterisation of multifunctional structural power composites, Journal of Composite Materials, Vol: 49, Pages: 1823-1834, ISSN: 1530-793X

Journal article

Yau HC, Bayazit MK, Steinke JHG, Shaffer MSPet al., 2014, Diamond Rings or Dumbbells: Controlling the Structure of Poly(ethylene glycol)-Fullerene [60] Adducts by Varying Linking Chain Length, MACROMOLECULES, Vol: 47, Pages: 4870-4875, ISSN: 0024-9297

Journal article

Shaffer MSP, Morishita T, Clancy AJ, 2014, Optimised exfoliation conditions enhance isolation and solubility of grafted graphenes from graphite intercalation compounds, Journal of Materials Chemistry A, Pages: 15022-15028, ISSN: 2050-7488

Journal article

Chen S, Hu S, Smith EF, Ruenraroengsak P, Thorley AJ, Menzel R, Goode AE, Ryan MP, Tetley TD, Porter AE, Shaffer MSPet al., 2014, Aqueous cationic, anionic and non-ionic multi-walled carbon nanotubes, functionalised with minimal framework damage, for biomedical application, Biomaterials, Vol: 35, Pages: 4729-4738

Journal article

Javaid A, Ho KKC, Bismarck A, Shaffer MSP, Steinke JHG, Greenhalgh ESet al., 2014, Multifunctional structural supercapacitors for electrical energy storage applications, JOURNAL OF COMPOSITE MATERIALS, Vol: 48, Pages: 1409-1416, ISSN: 0021-9983

Journal article

Goode AE, Hine NDM, Chen S, Bergin SD, Shaffer MSP, Ryan MP, Haynes PD, Porter AE, McComb DWet al., Mapping functional groups on oxidised multi-walled carbon nanotubes at the nanometre scale, Chemical Communications, ISSN: 1364-548X

Journal article

Boncel S, Pattinson SW, Geiser V, Shaffer MSP, Koziol KKKet al., 2014, En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays, BEILSTEIN JOURNAL OF NANOTECHNOLOGY, Vol: 5, Pages: 219-233, ISSN: 2190-4286

Journal article

Boncel S, Gorka J, Shaffer MSP, Koziol KKKet al., 2014, "Binary Salt" of Hexane-1,6-Diaminium Adipate and "Carbon Nanotubate" as a Synthetic Precursor of Carbon Nanotube/Nylon-6,6 Hybrid Materials, POLYMER COMPOSITES, Vol: 35, Pages: 523-529, ISSN: 0272-8397

Journal article

Brown NJ, Harris JE, Yin X, Silverwood I, White AJP, Kazarian SG, Hellgardt K, Shaffer MSP, Williams CKet al., 2014, Mononuclear phenolate diamine zinc hydride complexes and their Reactions with CO2, Organometallics, Vol: 33, Pages: 1112-1119, ISSN: 1520-6041

The synthesis, characterization, and zinc coordination chemistry of the three proligands 2-tert-butyl-4-[tert-butyl (1)/methoxy (2)/nitro (3)]-6-{[(2′-dimethylaminoethyl)methylamino]methyl}phenol are described. Each of the ligands was reacted with diethylzinc to yield zinc ethyl complexes 4–6; these complexes were subsequently reacted with phenylsilanol to yield zinc siloxide complexes 7–9. Finally, the zinc siloxide complexes were reacted with phenylsilane to produce the three new zinc hydride complexes 10–12. The new complexes 4–12 have been fully characterized by NMR spectroscopy, mass spectrometry, and elemental analyses. The structures of the zinc hydride complexes have been probed using VT-NMR spectroscopy and X-ray diffraction experiments. These data indicate that the complexes exhibit mononuclear structures at 298 K, both in the solid state and in solution (d8-toluene). At 203 K, the NMR signals broaden, consistent with an equilibrium between the mononuclear and dinuclear bis(μ-hydrido) complexes. All three zinc hydride complexes react rapidly and quantitatively with carbon dioxide, at 298 K and 1 bar of pressure over 20 min, to form the new zinc formate complexes 13–15. The zinc formate complexes have been analyzed by NMR spectroscopy and VT-NMR studies, which reveal a temperature-dependent monomer–dimer equilibrium that is dominated by the mononuclear species at 298 K.

Journal article

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