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

 
 
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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

235 results found

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

Anthony DB, Qian H, Clancy AJ, Greenhalgh ES, Bismarck A, Shaffer MSPet al., 2017, Applying a potential difference to minimise damage to carbon fibres during carbon nanotube grafting by chemical vapour deposition, NANOTECHNOLOGY, Vol: 28, ISSN: 0957-4484

JOURNAL ARTICLE

Buckley DJ, Hodge SA, De Marco M, Hu S, Anthony DB, Linden Cullen P, Skipper NT, Shaffer MSP, Howard CAet al., 2017, Trajectory of the Selective Dissolution of Charged Single-Walled Carbon Nanotubes, Journal of Physical Chemistry C, ISSN: 1932-7447

Single-Walled Carbon Nanotubes (SWCNTs) are materials with an array of remarkable physical properties determined by their geometries, however, SWCNTs are typically produced as a mixture of different lengths and electronic types. Consequently, many methods have been developed to sort the as-produced SWCNT samples by their physical cha-racteristics, often requiring aggressive and unscalable techniques to overcome the strong bundling forces between the nanotubes. Previously, it has been shown that negatively charging SWCNTs can lead to their thermodynamically-driven dissolution in polar solvents, and moreover that this process can selectively dissolve different SWNCT species, albeit with contrasting claims of selectivity. Here we carefully investigate dissolution as a function of charge added to the SWCNT starting material, using a range of complementary techniques. We uncover a far richer dependence on charge of SWCNT dissolution than previously reported. At low charge added, amorphous carbons preferentially dissolve, followed sequentially by metallic, larger diameter semiconducting SWCNTs, and finally smaller diameter semiconducting SWCNTs. At an optimal value, the dissolution yield is maximized across all species, however at higher charge than this we find the larger diameter and metallic SWCNTs are so charged they are no longer soluble, leaving smaller diameter SWCNTs in solution. Our results therefore clearly demonstrate two interconnected mechanisms for dissolution: on one hand charging of the SWNCTs based on their respective electron affinities on the other the solution thermodynamics. This work reconciles contrasting reports in the literature, provides a blueprint for scalable SWCNT separation and more generally demonstrates the..

JOURNAL ARTICLE

Clancy AJ, Anthony DB, Fisher SJ, Leese HS, Roberts CS, Shaffer MSPet al., 2017, Reductive dissolution of supergrowth carbon nanotubes for tougher nanocomposites by reactive coagulation spinning, NANOSCALE, Vol: 9, Pages: 8764-8773, ISSN: 2040-3364

JOURNAL ARTICLE

De Marco M, Menzel R, Bawaked SM, Mokhtar M, Obaid AY, Basahel SN, Shaffer MSPet al., 2017, Hybrid effects in graphene oxide/carbon nanotube-supported layered double hydroxides: enhancing the CO2 sorption properties, CARBON, Vol: 123, Pages: 616-627, ISSN: 0008-6223

JOURNAL ARTICLE

Garcia-Trenco A, White ER, Regoutz A, Payne DJ, Shaffer MSP, Williams CKet al., 2017, Pd2Ga-Based Colloids as Highly Active Catalysts for the Hydrogenation of CO2 to Methanol, ACS CATALYSIS, Vol: 7, Pages: 1186-1196, ISSN: 2155-5435

JOURNAL ARTICLE

Gonzalez Carter DA, Leo BF, Ruenraroengsak P, Chen S, Goode A, Theodorou I, Chung KF, Carzaniga R, Shaffer M, Dexter D, Ryan M, Porter Aet al., 2017, Silver nanoparticles reduce brain inflammation and related neurotoxicity through induction of H2S-synthesizing enzymes, Scientific Reports, Vol: 7, ISSN: 2045-2322

Silver nanoparticles (AgNP) are known to penetrate into the brain and cause neuronal death. However, there is a paucity in studies examining the effect of AgNP on the resident immune cells of the brain, microglia. Given microglia are implicated in neurodegenerative disorders such as Parkinson’s disease (PD), it is important to examine how AgNPs affect microglial inflammation to fully assess AgNP neurotoxicity. In addition, understanding AgNP processing by microglia will allow better prediction of their long term bioreactivity. In the present study, the in vitro uptake and intracellular transformation of citrate-capped AgNPs by microglia, as well as their effects on microglial inflammation and related neurotoxicity were examined. Analytical microscopy demonstrated internalization and dissolution of AgNPs within microglia and formation of non-reactive silver sulphide (Ag2S) on the surface of AgNPs. Furthermore, AgNP-treatment up-regulated microglial expression of the hydrogen sulphide (H2S)-synthesizing enzyme cystathionine-γ-lyase (CSE). In addition, AgNPs showed significant anti-inflammatory effects, reducing lipopolysaccharide (LPS)-stimulated ROS, nitric oxide and TNFα production, which translated into reduced microglial toxicity towards dopaminergic neurons. Hence, the present results indicate that intracellular Ag2S formation, resulting from CSE-mediated H2S production in microglia, sequesters Ag+ ions released from AgNPs, significantly limiting their toxicity, concomitantly reducing microglial inflammation and related neurotoxicity.

JOURNAL ARTICLE

Hart M, White ER, Chen J, McGilvery CM, Pickard CJ, Michaelides A, Sella A, Shaffer MSP, Salzmann CGet al., 2017, Encapsulation and Polymerization of White Phosphorus Inside Single-Wall Carbon Nanotubes, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 56, Pages: 8144-8148, ISSN: 1433-7851

JOURNAL ARTICLE

Hodge SA, Buckley DJ, Yau HC, Skipper NT, Howard CA, Shaffer MSPet al., 2017, Chemical routes to discharging graphenides, NANOSCALE, Vol: 9, Pages: 3150-3158, ISSN: 2040-3364

JOURNAL ARTICLE

Hu S, Laker ZPL, Leese HS, Rubio N, De Marco M, Au H, Skilbeck MS, Wilson NR, Shaffer MSPet al., 2017, Thermochemical functionalisation of graphenes with minimal framework damage, CHEMICAL SCIENCE, Vol: 8, Pages: 6149-6154, ISSN: 2041-6520

JOURNAL ARTICLE

Miller TS, Suter TM, Telford AM, Picco L, Payton OD, Russell-Pavier F, Cullen PL, Sella A, Shaffer MSP, Nelson J, Tileli V, McMillan PF, Howard CAet al., 2017, Single Crystal, Luminescent Carbon Nitride Nanosheets Formed by Spontaneous Dissolution., Nano Lett, Vol: 17, Pages: 5891-5896

A primary method for the production of 2D nanosheets is liquid-phase delamination from their 3D layered bulk analogues. Most strategies currently achieve this objective by significant mechanical energy input or chemical modification but these processes are detrimental to the structure and properties of the resulting 2D nanomaterials. Bulk poly(triazine imide) (PTI)-based carbon nitrides are layered materials with a high degree of crystalline order. Here, we demonstrate that these semiconductors are spontaneously soluble in select polar aprotic solvents, that is, without any chemical or physical intervention. In contrast to more aggressive exfoliation strategies, this thermodynamically driven dissolution process perfectly maintains the crystallographic form of the starting material, yielding solutions of defect-free, hexagonal 2D nanosheets with a well-defined size distribution. This pristine nanosheet structure results in narrow, excitation-wavelength-independent photoluminescence emission spectra. Furthermore, by controlling the aggregation state of the nanosheets, we demonstrate that the emission wavelengths can be tuned from narrow UV to broad-band white. This has potential applicability to a range of optoelectronic devices.

JOURNAL ARTICLE

Pike SD, Garcia-Trenco A, White ER, Leung AHM, Weiner J, Shaffer MSP, Williams CKet al., 2017, Colloidal Cu/ZnO catalysts for the hydrogenation of carbon dioxide to methanol: investigating catalyst preparation and ligand effectst, CATALYSIS SCIENCE & TECHNOLOGY, Vol: 7, Pages: 3842-3850, ISSN: 2044-4753

JOURNAL ARTICLE

Pike SD, Garcia-Trenco A, White ER, Leung AHM, Weiner J, Shaffer MSP, Williams CKet al., 2017, Colloidal Cu/ZnO catalysts for the hydrogenation of carbon dioxide to methanol: investigating catalyst preparation and ligand effects (vol 7, pg 3842, 2017), CATALYSIS SCIENCE & TECHNOLOGY, Vol: 7, Pages: 4233-4233, ISSN: 2044-4753

JOURNAL ARTICLE

Pike SD, White ER, Regoutz A, Sammy N, Payne DJ, Williams CK, Shaffer MSPet al., 2017, Reversible Redox Cycling of Well-Defined, Ultrasmall Cu/Cu2O Nanoparticles, ACS NANO, Vol: 11, Pages: 2714-2723, ISSN: 1936-0851

JOURNAL ARTICLE

Robinson RK, Birrell MA, Adcock JJ, Wortley MA, Dubuis ED, Chen S, McGilvery CM, Hu S, Shaffer MSP, Bonvini SJ, Maher SA, Mudway IS, Porter AE, Carlsten C, Tetley TD, Belvisi MGet al., 2017, Mechanistic link between diesel exhaust particles and respiratory reflexes., J Allergy Clin Immunol

BACKGROUND: Diesel exhaust particles (DEPs) are a major component of particulate matter in Europe's largest cities, and epidemiologic evidence links exposure with respiratory symptoms and asthma exacerbations. Respiratory reflexes are responsible for symptoms and are regulated by vagal afferent nerves, which innervate the airway. It is not known how DEP exposure activates airway afferents to elicit symptoms, such as cough and bronchospasm. OBJECTIVE: We sought to identify the mechanisms involved in activation of airway sensory afferents by DEPs. METHODS: In this study we use in vitro and in vivo electrophysiologic techniques, including a unique model that assesses depolarization (a marker of sensory nerve activation) of human vagus. RESULTS: We demonstrate a direct interaction between DEP and airway C-fiber afferents. In anesthetized guinea pigs intratracheal administration of DEPs activated airway C-fibers. The organic extract (DEP-OE) and not the cleaned particles evoked depolarization of guinea pig and human vagus, and this was inhibited by a transient receptor potential ankyrin-1 antagonist and the antioxidant N-acetyl cysteine. Polycyclic aromatic hydrocarbons, major constituents of DEPs, were implicated in this process through activation of the aryl hydrocarbon receptor and subsequent mitochondrial reactive oxygen species production, which is known to activate transient receptor potential ankyrin-1 on nociceptive C-fibers. CONCLUSIONS: This study provides the first mechanistic insights into how exposure to urban air pollution leads to activation of guinea pig and human sensory nerves, which are responsible for respiratory symptoms. Mechanistic information will enable the development of appropriate therapeutic interventions and mitigation strategies for those susceptible subjects who are most at risk.

JOURNAL ARTICLE

Rocha VG, García-Tuñón E, Botas C, Markoulidis F, Feilden E, D'Elia E, Ni N, Shaffer M, Saiz Eet al., 2017, Multimaterial 3D Printing of Graphene-Based Electrodes for Electrochemical Energy Storage Using Thermoresponsive Inks., ACS Appl Mater Interfaces

The current lifestyles, increasing population, and limited resources result in energy research being at the forefront of worldwide grand challenges, increasing the demand for sustainable and more efficient energy devices. In this context, additive manufacturing brings the possibility of making electrodes and electrical energy storage devices in any desired three-dimensional (3D) shape and dimensions, while preserving the multifunctional properties of the active materials in terms of surface area and conductivity. This paves the way to optimized and more efficient designs for energy devices. Here, we describe how three-dimensional (3D) printing will allow the fabrication of bespoke devices, with complex geometries, tailored to fit specific requirements and applications, by designing water-based thermoresponsive inks to 3D-print different materials in one step, for example, printing the active material precursor (reduced chemically modified graphene (rCMG)) and the current collector (copper) for supercapacitors or anodes for lithium-ion batteries. The formulation of thermoresponsive inks using Pluronic F127 provides an aqueous-based, robust, flexible, and easily upscalable approach. The devices are designed to provide low resistance interface, enhanced electrical properties, mechanical performance, packing of rCMG, and low active material density while facilitating the postprocessing of the multicomponent 3D-printed structures. The electrode materials are selected to match postprocessing conditions. The reduction of the active material (rCMG) and sintering of the current collector (Cu) take place simultaneously. The electrochemical performance of the rCMG-based self-standing binder-free electrode and the two materials coupled rCMG/Cu printed electrode prove the potential of multimaterial printing in energy applications.

JOURNAL ARTICLE

Thong AZ, Shaffer MSP, Horsfield AP, 2017, HOMO-LUMO coupling: the fourth rule for highly effective molecular rectifiers, NANOSCALE, Vol: 9, Pages: 8119-8125, ISSN: 2040-3364

JOURNAL ARTICLE

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

Bayazit MK, Hodge SA, Clancy AJ, Menzel R, Chen S, Shaffer MSPet al., 2016, Carbon nanotube anions for the preparation of gold nanoparticle-nanocarbon hybrids, CHEMICAL COMMUNICATIONS, Vol: 52, Pages: 1934-1937, ISSN: 1359-7345

JOURNAL ARTICLE

Blaker JJ, Anthony DB, Tang G, Shamsuddin S-R, Kalinka G, Weinrich M, Abdolvand A, Shaffer MSP, Bismarck Aet al., 2016, Property and Shape Modulation of Carbon Fibers Using Lasers, ACS APPLIED MATERIALS & INTERFACES, Vol: 8, Pages: 16351-16358, ISSN: 1944-8244

JOURNAL ARTICLE

Chen S, Goode AE, Skepper JN, Thorley AJ, Seiffert JM, Chung KF, Tetley TD, Shaffer MSP, Ryan MP, Porter AEet al., 2016, Avoiding artefacts during electron microscopy of silver nanomaterials exposed to biological environments, JOURNAL OF MICROSCOPY, Vol: 261, Pages: 157-166, ISSN: 0022-2720

JOURNAL ARTICLE

Clancy AJ, White ER, Tay HH, Yau HC, Shaffer MSPet al., 2016, Systematic comparison of conventional and reductive single-walled carbon nanotube purifications, CARBON, Vol: 108, Pages: 423-432, ISSN: 0008-6223

JOURNAL ARTICLE

De Marco M, Markoulidis F, Menzel R, Bawaked SM, Mokhtar M, Al-Thabaiti SA, Basahel SN, Shaffer MSPet al., 2016, Cross-linked single-walled carbon nanotube aerogel electrodes via reductive coupling chemistry, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 4, Pages: 5385-5389, ISSN: 2050-7488

JOURNAL ARTICLE

Diba M, Fam DWH, Boccaccini AR, Shaffer MSPet al., 2016, Electrophoretic deposition of graphene-related materials: A review of the fundamentals, PROGRESS IN MATERIALS SCIENCE, Vol: 82, Pages: 83-117, ISSN: 0079-6425

JOURNAL ARTICLE

Ferguson A, Khan U, Walsh M, Lee K-Y, Bismarck A, Shaffer MSP, Coleman JN, Bergin SDet al., 2016, Understanding the Dispersion and Assembly of Bacterial Cellulose in Organic Solvents, BIOMACROMOLECULES, Vol: 17, Pages: 1845-1853, ISSN: 1525-7797

JOURNAL ARTICLE

Garcia-Trenco A, White ER, Shaffer MSP, Williams CKet al., 2016, A one-step Cu/ZnO quasi-homogeneous catalyst for DME production from syn-gas, CATALYSIS SCIENCE & TECHNOLOGY, Vol: 6, Pages: 4389-4397, ISSN: 2044-4753

JOURNAL ARTICLE

Govada L, Leese HS, Saridakis E, Kassen S, Chain B, Khurshid S, Menzel R, Hu S, Shaffer MSP, Chayen NEet al., 2016, Exploring Carbon Nanomaterial Diversity for Nucleation of Protein Crystals, SCIENTIFIC REPORTS, Vol: 6, ISSN: 2045-2322

JOURNAL ARTICLE

Herceg TM, Abidin MSZ, Greenhalgh ES, Shaffer MSP, Bismarck Aet al., 2016, Thermosetting hierarchical composites with high carbon nanotube loadings: En route to high performance, Composites Science and Technology, Vol: 127, Pages: 134-141, ISSN: 0266-3538

A wet powder impregnation route to manufacture carbon fibre reinforced thermoplastic composites was adapted to accommodate thermosetting matrices reinforced with high fractions (20 wt%/13.6 vol%) of multiwalled carbon nanotubes (CNTs). The produced carbon fibre prepregs were consolidated into laminates with fibre volume fractions of 50–58% and up to 6.1 vol% CNTs. Microscopic imaging confirmed successful consolidation at intermediate CNT loadings, but some voidage at the highest CNT loading due to the highly viscoelastic uncured matrix. Nonetheless, through-thickness electrical conductivity and Mode I interlaminar fracture toughness were enhanced by as much as 152% and 24% to unprecedented values of σ = 53 S m−1 and GIC = 840 J m−2, respectively. Fractographic characterisation indicated that crack deflection was the mechanism responsible for the improved fracture toughness. The material properties were shown to be strongly dependent on the microstructure of the matrix.

JOURNAL ARTICLE

Herceg TM, Yoon S-H, Abidin MSZ, Greenhalgh ES, Bismarck A, Shaffer MSPet al., 2016, Thermosetting nanocomposites with high carbon nanotube loadings processed by a scalable powder based method, COMPOSITES SCIENCE AND TECHNOLOGY, Vol: 127, Pages: 62-70, ISSN: 0266-3538

JOURNAL ARTICLE

Javaid A, Ho KKC, Bismarck A, Steinke JHG, Shaffer MSP, Greenhalgh ESet al., 2016, 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: 0021-9983

JOURNAL ARTICLE

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