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Dr Ray Whitby

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contact:
Pharmacy and Biomolecular Sciences
Moulsecoomb
Brighton
BN2 4GJ

Email: R.Whitby@brighton.ac.uk

Research Interests

  • Chemistry of nanoscale materials for optimisation of properties, surface chemistry and architecture;
  • Tailoring of chemical functionality towards development of biomaterials for nerve cell repair, wound dressing and drug delivery, polymer composite generation and catalytic performance;
  • Synthesis and chemical tailoring of nanomaterials and nanocomposites for adsorption and/or destruction of organic, inorganic, heavy metal and radionuclide contaminants from water, including optimisation of substrate-nanomaterial configuration;
  • UV dissociation of critically opalescent carbon dioxide for nanomaterial production, including elucidation of catalytic transformation mechanisms of feedstock into controlled architecture.

Profile

Raymond Whitby is a reader in Chemistry of Nanomaterials and Head of the Nanoscience and Nanotechnology Group at the University of Brighton (www.brighton.ac.uk/nano) and head of the Brighton node of Global Education Outreach in Science, Engineering and Technology (GEOSET). His research interests primarily involve chemistry of nanomaterials and currently focuses on its application to composite formulation for improved mechanical and accoustical performance, also stemming to biomaterials for bone scaffolds or nerve cell growth constructs, target therapy for drug delivery or cancer treatment, novel water/wastewater treatment processes, carbon dioxide dissociation to nanomaterials.

He graduated from the University of Bradford with an Honours degree in Chemistry with Pharmaceutical and Forensic Science and completed his PhD under Prof Sir Harry Kroto (Nobel Laureate 1996 for buckminster fullerenes) at the University of Sussex on "Nanocomposites of Carbon & Tungsten Disulphide". He then spent six months researching at the Bio-Nanotechnology Electronics Research Centre at Toyo University, having obtained a Japanese Society for the Promotion of Science Fellowship, and later appointed Visiting Professor.

Raymond Whitby is an RCUK Academic Fellow at the University of Brighton in Nanotechnology; he won two University Innovation Awards (in business translation of research) and a Triple Science Network Award (in partnership with the STEM Sussex outreach group). He currently coordinates grants from EU FP7 programmes Industry Academia Partnership and Pathways and International Research Staff Exchange Scheme and privately funded projects with national/international SMEs.


Feature Article

Tiny Silver Particles Trap Mercury (Review by Dr Kristin Madefessel-Herrmann)

Hyperstoichiometric reaction between mercury ions and silver nanoparticles reported in Angewandte Chemie

Anyone who thinks amalgams are limited to tooth fillings is missing something: Amalgams, which are alloys of mercury and other metals, have been used for over 2500 years in the production of jewelry and for the extraction of metals like silver and gold in mining operations. These days, the inverse process is of greater interest: the removal of mercury from wastewater by amalgamation with precious metals in the form of nanoparticles. Kseniia Katok and colleagues have now reported new insights in the journal Angewandte Chemie: if the diameter of silver nanoparticles is made even smaller, significantly more mercury can be extracted relative to the amount of silver used.

In the conventional process, two silver atoms react with one mercury ion, which carries a twofold positive charge, to produce two silver ions, which go into solution, and a neutral mercury atom, which is taken up by the metallic silver particles. The stoichiometric ratio of mercury to silver is thus 1:2. Read more.


Research Publications

For reprints please contact Dr Raymond Whitby via email (r.whitby@brighton.ac.uk) or download from his personal website (www.whitbyresearch.co.uk).

2012

53. Ortrud Aschenbrenner, Takahiro Fukuda, Takashi Hasumura, Toru Maekawa, Vladimir M. Gun'ko, Sergey V. Mikhalovsky, Andrew B. Cundy, and Raymond L.D. Whitby, "Creation of 3-Dimensional Carbon Nanostructures from UV Irradiation of Carbon Dioxide at Room Temperature", of Supercritical Fluids, accepted 2012.

52. Raymond L.D. Whitby, Takahiro Fukuda, Toru Maekawa. "Macro-scale complexity of nano- to micro-scale architecture of olivine crystals through an iodine vapour transport mechanism", Bulletin of Materials Science, accepted 2012.

51. Raymond L.D. Whitby, Vladimir M. Gun'ko, Alina Korobeinyk, Rosa Busquets, Andrew B. Cundy, Krisztina László, Jadwiga Skubiszewska-Zięba, Roman Leboda, Etelka Tombácz, Ildiko Y. Toth, Krisztina Kovacs, Sergey V. Mikhalovsky. "Driving Forces of Conformational Changes in Single-Layer Graphene Oxide", ACS Nano, 6, 3967–3973 (2012). Abstract: The extensive oxygen-group functionality of single-layer graphene oxide proffers useful anchor sites for chemical functionalization in the controlled formation of graphene architecture and composites. However, the physicochemical environment of graphene oxide and its single-atom thickness facilitate its ability to undergo conformational changes due to responses to its environment, whether pH, salinity, or temperature. Here, we report experimental and molecular simulations confirming the conformational changes of single-layer graphene oxide sheets from the wet or dry state. MD, PM6, and ab initio simulations of dry SLG and dry and wetted SLGO and electron microscopy imaging show marked differences in the properties of the materials that can explain variations in previously observed results for the pH dependent behavior of SLGO and electrical conductivity of chemically modified graphene-polymer composites. Understanding the physicochemical responses of graphene and graphene oxide architecture and performing selected chemistry will ultimately facilitate greater tunability of their performance. Free copy graphene geometry .pdf

50. Yanqiu Zhu, Raymond L.D. Whitby, Renzhi Ma, Steve F.A. Acquah, 1D Nanomaterials 2011, 535697 (2012). DOI: http://dx.doi.org/10.1155/2012/535697. 1D Nanomaterials .pdf

49. Ortrud Aschenbrenner, Takahiro Fukuda, Takashi Hasumura, Toru Maekawa, Andrew B. Cundy, Raymond L. D. Whitby, "Creation of spherical carbon nanoparticles and clusters from carbon dioxide via UV dissociation at the critical point", Green Chemistry, 14, 1196-1201 (2012). DOI: http://dx.doi.org/10.1039/c2gc16593g. Abstract: Carbon nanomaterials have become increasingly important for many applications, including sensors, electronics, biomedical materials and functional composites. Currently their production is based on hydrocarbons or graphite and requires very high temperatures. Here we present a method for the synthesis of carbon nanomaterials from carbon dioxide. Unlike previously described methods, our synthesis method works near room temperature. Carbon dioxide is irradiated at its critical point, producing spherical carbon nanoparticles even without the use of a catalyst. We examine the influence of irradiation parameters and different metals and catalysts on the nanocarbon production. Together with analysis of the fluid phase, this allows us to draw some conclusions on the carbon dioxide dissociation mechanism. CO2 Green Chemistry .pdf

2011

48. Lyudmyla V. Karabanova, Raymond L. D. Whitby, Alina Korobeinyk, Oksana Bondaruk, Jonathan P. Salvage, Andrew W. Lloyd, Sergey V. Mikhalovsky, "Microstructure changes of polyurethane by inclusion of chemically modified carbon nanotubes at low filler contents", Composites Science and Technology, accepted 2012. Abstract: The surface of multi-walled carbon nanotubes (MWCNTs) was modified to introduce acidic groups in either covalent or van der Waals interaction bonding environments to establish cross-linking sites with a host polymer. Nanocomposites based on a polyurethane matrix (PU) containing chemically functionalized multi-walled carbon nanotubes (MWCNTs) have been shown to alter its mechanical performance depending on the nature of the surface functional groups on MWCNTs, which correlates to the type of bonding interaction of the surface group and also the dispersibility of MWCNTs and their influence on the domain structure of polyurethane. The stress at break for nanocomposites containing 0.25 wt% of acid-oxidised MWCNTs (MWCNT-ox), bearing covalently attached carboxylic, lactone and phenolic groups, was twice that of the native PU and Young's Modulus for the nanocomposites increased by 4 times. Whereas when hemin, which contains carboxylic functionality, was immobilised to the surface of pure MWCNTs, the improvement in Young's Modulus was only around twice that of pure PU. Differences in the disaggregation of MWCNTs into PU were observed between the samples as well as variation of the native domain structure of PU. The results also infer that the purification of MWCNTs from acid-oxidative lattice fragments (fulvic acids) is vital prior to conducting surface chemistry and polymerisation in order to ensure maximum mechanical performance enhancement in their reinforcement of the host polymer.

47. Kseniia V. Katok, Raymond L. D. Whitby, Takahiro Fukuda, Toru Maekawa, Igor Bezverkhyy, Sergey V. Mikhalovsky, and Andrew B. Cundy, "Hyperstoichiometric Interaction Between Silver and Mercury at the Nanoscale", Angewandte Chemie International Edition, Early View 3 Feb 2012. Abstract: Extraction of heavy metals (e.g. silver, gold) through the formation of amalgams with mercury has been utilized in jewellery production[1] and mining[2] for over 2500 years. This has been contemporarily applied in a nanoformulation for the opposite process with the abstraction of mercury from waste sources using zero-valent nanoparticles of noble metals.[3] The interaction of metal nanoparticles with other species has shown great promise for a number of applications[4] and in particular silver nanoparticles (AgNPs) have been used as an anti-microbial agent in textiles and composites[5] and also (less frequently) for the destruction of pesticides or the removal of mercury from industrial effluents and other waters.[6]With the formation of silver through a silicon hydride reduction, we expect that as the size of the particle is reduced to the nanoscale its interaction with aqueous mercury will be dominated by surface forces.

46. Alina Korobeinyk, Raymond L.D. Whitby, Jonathan P. Salvage, Sergey V. Mikhalovsky, "Exfoliated production of single- and multi-layer graphenes and carbon nanofibres from the carbonization of a co-polymer", Carbon, 50, 2018-2025 (2012). Abstract: Non-catalysed growth methodologies of carbon nanomaterial synthesis can represent lower costs and greener approaches and cause less damage to the nanomaterial. During the carbonization of a polyacrylonitrile-based co-polymer, carbon nanofibres (CNFs) and single- and multi-layer graphenes (SLG and MLG) are generated. The accumulated fragmentation products of the co-polymer coalesce to form CNFs that radiate away from the monolith, whose dimensions are linked to their template growth along crests, which were formed from the out-gassing of volatile products of the polymer during the stabilisation step. The slight shrinkage of the carbonizing monolith also leads to exfoliation of larger areas of the surface yielding single- and multi-layered graphenes. These results reveal a potentially useful process for the facile production of carbon nanomaterials. Graphene production .pdf

45. Alina Korobeinyk, Raymond L.D. Whitby, Sergey V. Mikhalovsky, "High temperature oxidative resistance of polyacrylonitrile-methylmethacrylate copolymer powder converting to a carbonized monolith", European Polymer Journal (accepted 2011). Abstract: The doping of polyacrylonitrile (PAN) prior to carbonization can alter the physicochemical nature of the polymer under thermal treatment. The inclusion of a “lower” thermally stable monomer methylmethacrylate (MMA) enables fusion of PAN particles into monoliths and, depending on the heating rate, can control the expansion of the structure and establish pore formation through the volatilisation and escape of its thermal degradation products. Moreover, geometry is maintained through the carbonization step, when heated up to 850 °C. The exothermic regime of PAN-co-MMA is much broader and the cyclization reaction starts at a lower temperature compared with that of the PAN homopolymer. TGA reveals that the thermal stability of the copolymer, compared with pure PAN at 800 °C, has increased by 30 wt % in air, which is far higher than reported in previous studies of copolymers of PAN. The results show promise in providing a facile mechanism for the production of monolithic PAN-based carbons with the potential of controlled porosity.

44. Takahiro Fukuda, Yoshihiro Katsube, Nami Watabe, Shunji Kurosu, Raymond L.D. Whitby, Toru Maekawa, "Nano clusters composed of C60 molecules deposit in C60 benzene solution under near critical conditions of benzene", Journal of Supercritical Fluid, 58, 407-411 (2011). DOI: 10.1016/j.supflu.2011.07.006. Abstract: We dissolve C60, C70 or C84 molecules in benzene and change the fluid state from a gas-liquid two-phase region (25.0 °C) to the critical point (289.0 °C) and from the critical point to the original state (25.0 °C) along the gas-liquid coexistence curve. We find that particle-like and whisker-like nano/micro clusters, which are composed of C60 molecules, deposit on the surface of a silicon substrate placed vertically in C60/benzene solution during the temperature change, whereas no appreciable clusters were detected on the silicon substrate in either C70/benzene or C84/benzene solutions. The clusters, in which fcc lattice structures are formed by C60 molecules, remain stable in the solution. The present result suggests that C60 molecules can be separated and extracted from a mixture of C60, C70 and C84 molecules dissolved in benzene.

43. Raymond L.D. Whitby, Alina Korobeinyk, Vladimir M. Gun’ko, Rosa Busquets, Andrew B. Cundy, Krisztina Laszlo, Jadwiga Skubiszewska-Zięba, Roman Leboda, Etelka Tombacz, Ildiko Toth, Krisztina Kovacs, Sergey V. Mikhalovsky, "pH-driven physicochemical conformational changes of single-layer graphene oxide", Chem. Comm., 47, 9645-9647 (2011). Abstract: Single-layer graphene oxides (SLGO) undergo morphological changes depending on the pH of the system and may account for restricted chemical reactivity. Herein, SLGO may also capture nanoparticles through layering and enveloping when the pH is changed, demonstrating potential usefulness in drug delivery or waste material capture. pH effects graphene chemistry.pdf

42. Raymond L.D. Whitby, Alina Korobeinyk, Sergey V. Mikhalovsky, Takahiro Fukuda, Toru Maekawa, "Morphological effects of single-layer graphene oxide in the formation of covalently bonded polypyrrole composites using intermediate diisocyanate chemistry", Journal of Nanoparticle Research, 13, 4829-4837 (2011). Abstract: Single-layer graphene oxide (SLGO) possesses carboxylic and hydroxyl groups suitable for reactions with aliphatic or aromatic diisocyanate molecules. TEM analysis reveals that aliphatic diisocyanate molecules caused SLGO to scroll into star-like formations, whereas aromatic diisocyanate molecules retained SGLO in a flat-sheet morphology. TGA confirms the stabilisation of the formed urea and urethane groups on SLGO, but the onset of sheet pyrolysis occurs at a lower temperature due to isocyanate reactions with anhydride and epoxide groups embedded in the sheet. Pendant isocyanate groups act as bridging units to facilitate the attachment of pyrrole molecules, which are then used as anchor sites for the covalent polymerisation of pyrrole to polypyrrole (PPy). The use of FeCl3 as the polymerisation catalyst generated both covalent and free PPy, but also iron hydroxide nanoparticles were observed decorating the SLGO surface. When using ammonium persulfate as a catalyst and dodecylbenzenesulfonate as a dopant, free PPy could be removed under treatment with solvents to leave a purely covalent system. Discrete regions of SLGO were observed decorated with nanoparticles of PPy along the edge or across the surface of individual sheets. It was found that the flexibility of the SLGO sheet and the type of diisocyanate used directly affected the electrical resistance of the final composite. graphene polypyrrole.pdf

41. I.N. Savina, C. English, R.L.D. Whitby, Y. Zheng, A. Leistner, S.V. Mikhalovsky, A.B. Cundy, "High Efficiency Removal of Dissolved As (III) using Iron Nanoparticle-Embedded Macroporous Polymer Composites", Journal of Hazardous Materials, 192, 1002-8 (2011). Abstract: Novel nanocomposite materials where iron nanoparticles are embedded into the walls of a macroporous polymer were produced and their efficiency for the removal of As(III) from aqueous media was studied. Nanocomposite gels containing α-Fe2O3 and Fe3O4 nanoparticles were prepared by cryopolymerization resulting in a monolithic structure with large interconnected pores up to 100 μm in diameter and possessing a high permeability (ca. 3 * 10-3 m s-1). The nanocomposite devices showed excellent capability for the removal of trace concentrations of As(III) from solution, with a total capacity of up to 3 mg As / per gram of nanoparticles. The leaching of iron was minimal and the device could operate in a pH range 3–9 without diminishing removal efficiency. The effect of competing ions such as SO4^-2 and PO4^-3 was negligible. The macroporous composites can be easily configured into a variety of shape and structures and the polymer matrix can be selected from a variety of monomers, offering high potential as flexible metal cation remediation devices. nanoiron composites.doc

40. Kateryna V. Voitko, Raymond L.D. Whitby, Vladimir M. Gun’ko, Olga M. Bakalinska, Mykola T. Kartel, Krisztina Laszlo, Andrew B. Cundy, Sergey V. Mikhalovsky, "Morphological and chemical features of nano- and macroscale carbons affecting hydrogen peroxide decomposition in aqueous medium", Journal of Colloid and Interface Science, 361, 129-136 (2011). Abstract: Chemical and structural factors of carbon materials affect their activity in adsorption and surface reactions in aqueous media. Decomposition of hydrogen peroxide studied is a probe reaction for exploring parameters of carbons that might be involved, such as specific surface area, nitrogen and oxygen doping and conformational changes. To date, a detailed comparison of the behavior of carbon nanoscale (Carbon Nanotubes, CNT, Single Layer Graphene Oxide, SLGO) with macroscale (Activated Carbons, AC) materials in this reaction has not been forthcoming. Herein, we demonstrate that on their first cycle, ACs in doped and undoped forms outperform all nanoscale carbons tested in the H2O2 decomposition. Among the nanocarbons, nitrogen-doped CNT exhibited the highest activity in this reaction. However, subsequent recycling of each carbon, without chemical regeneration between uses, reveals SLGO exhibits greater reaction rate stability over an extended number of cycles (n > 8) than other carbons including nitrogen-doped CNT and ACs. The effects of pH, temperature and concentration on the reaction were analyzed. Quantum chemical modeling and reaction kinetics analysis reveal key processes likely involved in hydrogen peroxide decomposition and show evidence of the reaction rate linked to the active sites with N- and O-containing functionalities. graphene catalysis.pdf and nanocarbon catalysis SI.doc

39. A.V. Korobeinyk, R.L.D. Whitby, J.J. Niu, Y. Gogotsi, S.V. Mikhalovsky, "Rapid assembly of carbon nanotube-based magnetic composites", Materials Chem. Phys., 128, 514-518 (2011). Paper: The rapid assembly of magnetic carbon nanotubes is mediated through the electrostatic attraction of α-haemetite nanoparticles to carboxylic groups decorating their outer surface. The system is then stabilised through covalently bonding a silica coat using a 3-aminopropyltriethoxysilane precursor, which creates a thin barrier protecting the α-haemetite particles from aggressive pH solutions. The nanocomposites can be effectively dispersed in aqueous solution and can be attracted to an external magnetic field. The proposed method can be used for synthesis of magnetic CNTs suitable for assembling densely packed magnetic arrays, remotely guided drug delivery and organic chemical wastewater remediation with the added benefit of nanomaterial recovery. magnetic carbon nanotubes.pdf

38. Z. Wang, R.L.D. Whitby, M. Rousseau, S. Nevill, G. Geaves, S.V. Mikhalovsky, "Vibration reduction ability of MWCNT PVAc composites measured under high frequency for acoustic device application", J. Mater. Chem., 21, 4150-4155 (2011). Paper: Through the functionalization strategy of multi-walled carbon nanotubes (MWCNTs) with polyvinyl acetate (PVAc), dampening material for acoustic devices was sought. In this paper, we investigated the effect of polymer grafting of MWCNTs on the frequency response based on a mechanistic basis. We have found that vibration reduction ability of the MWCNTs incoporated polymer has a maximum increase of 70% compared with pure polymer. Composites with pristine MWCNTs and polymer grafted MWCNTs were found to exhibit similar dynamic mechanical behavior in the frequency above 1000 Hz. carbon nanotube accoustics.pdf

37. R.L.D. Whitby, A. Korobeinyk, K.V. Glevatska, "Morphological changes and covalent reactivity assessment of single-layer graphene oxides under carboxylic group-targeted chemistry", Carbon, 49, 722-725 (2011). Paper: Acid-base titrations were used to assess the covalent reactivity of carboxylic groups on single-layer graphene oxides (SLGO) or hydrazine-reduced analogues (SLGR) when treated with thionyl chloride and subsequent coupling to amines. Reflux with aggressive solvents led to size reduction and folding of individual sheets as well as loss of carboxylic groups, substantially so for SLGR. Room temperature treatment of SLGO with N-hydroxysuccinimide collapsed the sheets into star-like clusters, which exhibited poor subsequent reactivity with carbodiimides and amines. Ultimately, conventional chemical treatment of carboxylic groups on SLGO leads to morphological changes and reduced reactivity, which may potentially limit their use. graphene chemistry.pdf and graphene chemistry supporting information.pdf

36. Takashi Hasumura, Takahiro Fukuda, Raymond L.D. Whitby, Ortrud Aschenbrenner and Toru Maekawa, "Low temperature synthesis of iron containing carbon nanoparticles in critical carbon dioxide", Journal of Nanoparticle Research, 13, 53-58 (2011). Paper: We develop a low temperature, organic solvent-free method of producing iron containing carbon (Fe@C) nanoparticles. We show that Fe@C nanoparticles are self-assembled by mixing ferrocene with sub-critical (25.0 °C), near-critical (31.0 °C and super-critical (41.0 °C) carbon dioxide and irradiating the solutions with UV laser of 266-nm wavelength. The diameter of the iron particles varies from 1 to 100 nm, whereas that of Fe@C particles ranges from 200 nm to 1000 nm. Bamboo-shaped structures are also formed by iron particles and carbon layers. There is no appreciable effect of the temperature on the quantity and diameter distributions of the particles produced. The Fe@C nanoparticles show soft ferromagnetic characteristics. Iron particles are crystallised, composed of bcc and fcc lattice structures, and the carbon shells are graphitised after irradiation of electron beams. carbon particles from critical CO2.pdf

2010

35. R.L.D. Whitby, S.F.A. Acquah, R. Ma, Y. Zhu, "1 Dimensional Nanomaterials", J. Nanomater., 597851, (2011). 1D nanomaterials.pdf

34. R.L.D. Whitby, V. Gun’ko, T. Fukuda, T. Maekawa, “Relating bulk resistivity to nanoscale mechanical responses of carbon nanotubes randomly orientated in monoliths under compression”, Carbon, 48, 3635-3637 (2010). Paper: The bulk electrical resistivity of randomly orientated multi-walled carbon nanotubes assembled into monoliths was monitored under uniaxial compression-expansion cycling, which exhibited a linear response in the range of ε= 20 to 40%. In situ scanning electron microscopy of the compression and expansion steps detailed the mechanical response of individual carbon nanotubes and indicated that their localised, nonlinear responses account for the subtle deviations from the theoretical consideration of electrical resistivity under applied strains. carbon nanotube buckycolumn electrical resistivity.pdf

33. T. Hasumura, T. Fukuda, R.L.D. Whitby, O. Aschenbrenner, T. Maekawa “Low temperature synthesis of fibres composed of carbon-nickel nanoparticles in super-critical carbon dioxide”, Chemical Physics Letters, 493, 304-308 (2010). Abstract: We show that fibres composed of carbon-nickel nanoparticles are self-assembled by mixing nickelocene and oxygen with super-critical carbon dioxide in a dc electric field. The fibres grow in the direction of the electric field and the growth rate increases with an increase in the strength of the electric field. We also irradiate the fibres with electron beams and find that crystallized nickel particles are captured by carbon particles. The present result suggests that a low temperature method of creating carbon-metal hybrid nanostructures may be developed by mixing metallocene and trigger molecules with super-critical fluids subjected to a dc electric field.

32. K. Matsumoto, C. Sato, Y. Naka, R.L.D. Whitby, N. Shimizu,"Stimulation of neuronal neurite outgrowth using functionalized carbon nanotubes", Nanotechnology, 21, 115101 (2010). Abstract: Low concentrations (0.11-1.7 µg ml - 1) of functionalized carbon nanotubes (CNTs), which are multi-walled CNTs modified by amino groups, when added with nerve growth factor (NGF), promoted outgrowth of neuronal neurites in dorsal root ganglion (DRG) neurons and rat pheochromocytoma cell line PC12h cells in culture media. The quantity of active extracellular signal-regulated kinase (ERK) was higher after the addition of both 0.85 µg ml - 1 CNTs and NGF than that with NGF alone. CNTs increased the number of cells with neurite outgrowth in DRG neurons and PC12h cells after the inhibition of the ERK signaling pathway using a mitogen-activated protein kinase (MAPK)/ERK kinase (MEK) inhibitor. Active ERK proteins were detected in MEK inhibitor-treated neurons after the addition of CNTs to the culture medium. These results demonstrate that CNTs may stimulate neurite outgrowth by activation of the ERK signaling pathway. Thus, CNTs are biocompatible and are promising candidates for biological applications and devices. nanotube stimulation of neurites.pdf

31. R.L.D. Whitby, S.V. Mikhalovsky, V.M. Gun’ko, “Mechanical performance of highly compressible multi-walled carbon nanotube columns with hyperboloid geometries”, Carbon, 48, 145 (2010). Paper: Multi-walled carbon nanotube (MWCNT) columns are formed from the frit compression of a random distribution of MWCNTs in a casting solvent; its drying led to the formation of hyperboloid geometry. Uniaxial loading of MWNT columns mimics an open-cell foam behaviour and possesses an expansion rate in excess of 250mm min-1 and an elastic modulus of 10-12 MPa, thus superior to conventional low-density flexible foams. Successive compression-expansion cycling within the Hookean region reveals a hysteresis loop in the stress-strain curve that stabilises at a final value of εF = 18%, but on contact with its casting solvent and subsequent drying, the sample can be regenerated to within εR = 6% according to a memory effect and is repeatable in successive stress cycles and solvent regeneration. The system was modelled for the macroscopic stress-strain behaviour of the MWCNT column to reveal the contributions of linear dependence, elasticity-plasticity and elasticity-plasticity with hardening, revealing good agreement with the stress-strain data. MWCNT columns should prove useful as an energy adsorbing device. carbon nanotube buckycolumn mehanical performance.pdf

30. Z. Wang, A. Korobeinyk, R.L.D. Whitby, S.T. Meikle, S.V. Mikhalovsky, S.F.A. Aquah, H.W. Kroto, “Direct confirmation that carbon nanotubes still react covalently after removal of acid oxidative lattice fragments”, Carbon, 48, 916 (2010). Abstract: With careful removal of acid-oxidative lattice fragments and use of acid-base titrations, the covalent reactivity of covalently bound carboxylic groups on multi-walled carbon nanotube surfaces has been directly confirmed, including intermediate states, for carbodiimide promoted amidation reactions. covalent carbon nanotube chemistry.pdf

29. R.L.D. Whitby, T. Fukuda, T. Maekawa, S.V. Mikhalovsky, A.B. Cundy, "Real-time imaging of complex nanoscale mechanical responses of carbon nanotubes in highly compressible porous monoliths", Nanotechnology, 21, 075707 (2010). Paper: A facile and rapid assembly of powdered carbon nanotubes (CNTs) into compressible, porous, macroscale monoliths is reported. Despite a Poisson's ratio just above zero, we found that the sample under compression inside a scanning electron microscope (SEM) revealed CNT regions behaving in auxetic and vortex-like rotational modes as well as standard collapse responses. This method is crucial in understanding the macroscale behaviour based on the accumulation of nanoscale responses to an applied force. carbon nanotube buckycolumn compression.pdf

2009

28. Z. Wang, M.D. Shirley, S.T. Meikle, R.L.D. Whitby and S.V. Mikhalovsky, "The surface acidity of acid oxidised multi-walled carbon nanotubes and the influence of in-situ generated fulvic acids on their stability in aqueous dispersions", Carbon, 47, 73-79 (2009). Abstract: The oxidation of multi-walled carbon nanotubes (MWCNTs) with nitric acid was studied. In addition to the formation of oxygen-containing surface functional groups, the oxidative digestion of graphene caps and layers generated polycyclic aromatic substances, classified as fulvic acids (FAs). The latter remained immobilised on the MWCNT surface in acidic and neutral solutions but were released in basic pH solutions, which were subsequently separated, purified and characterised by high-performance liquid chromatography and mass spectrometry. Using acid-base titrations, the number of surface acidic functional groups was determined, which was shown to significantly decrease after FAs were removed. Depending on the length of oxidation, FAs account for up to 43% of the surface acidity of MWCNTs. The protonated solubilised fulvic acids can be readsorbed on the surface of oxidised or unfunctionalised MWCNTs, which assists the stability of carbon nanotube suspensions in the aqueous phase. carbon nanotube oxidation.pdf

27. K. Matsumoto, C. Sato, R. Whitby and N. Shimizu, “Carbon nanotubes stimulate neurite outgrowths of neurons by activation of MAPK/ERK signal transduction” , New Biotechnology, 25, Supplement 1, S27-S28 (2009).

2008

26. A.B. Cundy, L. Hopkinson and R.L.D. Whitby, "Use of iron-based technologies in contaminated land and groundwater remediation: A review", Science of The Total Environment, 400, 42-51 (2008). Abstract: Reactions involving iron play a major role in the environmental cycling of a wide range of important organic, inorganic and radioactive contaminants. Consequently, a range of environmental clean-up technologies have been proposed or developed which utilise iron chemistry to remediate contaminated land and surface and subsurface waters, e.g. the use of injected zero zero-valent iron nanoparticles to remediate organic contaminant plumes; the generation of iron oxyhydroxide-based substrates for arsenic removal from contaminated waters; etc. This paper reviews some of the latest iron based technologies in contaminated land and groundwater remediation, their current state of development, and their potential applications and limitations. nanoiron in remediation.pdf

25. R.L.D. Whitby, T. Fukuda, T. Maekawa, S.L. James, S.V. Mikhalovsky, "Geometric control and tuneable pore size distribution of buckypaper and buckydiscs", Carbon, 46, 949-956 (2008). Paper: The fabrication of buckypaper from unfunctionalised multi-walled carbon nanotubes (MWCNTs) without the aid of surfactants or surface modification techniques is accomplished through a novel and quick frit compression method. The dimensions can be controlled through the size of the syringe housing and the through the mass of carbon nanotubes added. Their thicknesses are typically much larger than surfactant-cast buckypaper, which have been synthesised from 120 μm up to 650 μm; whilst no nomenclature system exists to govern thicknesses for samples to be classified as paper, we refer to buckypaper with thicknesses greater than 500 μm as buckydiscs. Buckypaper and buckydiscs are mechanically robust to handle, flexible, stable in solvents and possess larger porosities than Triton-X100 cast buckypaper. They also exhibit a memory effect when bending wetted samples, returning to their former geometry on drying. Buckypaper and buckydiscs were studied by mercury intrusion porosimetry to reveal a distribution of mesopores and small macropores that is dependant on the surface tension of the casting solvent and therefore tuneable. Moreover, the frit compression system allows control over the 3-dimensional geometry of the buckydiscs during the casting process. carbon nanotube buckycolumn formation.pdf

24. K. Matsumoto, C. Sato, R.L.D. Whitby, N. Shimizu, "BIOT

2006-2007

23. T. Fukuda, N. Watabe, R. Whitby and T. Maekawa, "Creation of carbon onions and coils at low temperature in near-critical benzene irradiated with an ultraviolet laser", Nanotechnology, 18, 415604 (2007). Abstract: Gas-liquid coexistence curves terminate at their critical points, where second-order phase transitions occur. The specific heat and compressibility increase greatly as the fluid systems approach their critical points. As a result, thermal diffusion is suppressed and the perturbations of the temperature, pressure and density propagate as acoustic waves. In this paper, we irradiate near-critical benzene with a laser beam of 266 nm in wavelength, the energy flux of which is 1.3 and 3.9 mWmm(-2), and show that benzene is dissociated and various carbon nano/ microstructures such as carbon onions and coils are created. Carbon onions are produced in both subcritical ( 200 degrees C) and supercritical ( 290 degrees C) benzene, whereas carbon coils are produced on an alloy catalyst composed of ( Fe: Cr: Ni = 74: 18: 8) in supercritical benzene irradiated with a laser beam of 3.9 mWmm(-2). The operational temperature of the present method is much lower than that used in conventional carbon structure synthesizing methods and a large number of carbon structures, such as carbon onions and coils, are produced in supercritical benzene.

22. T. Fukuda, T. Maekawa, T. Hasumura, N. Rantonen, K. Ishii, Y. Nakajima, T. Hanajiri, Y. Yoshida, R. Whitby and S. Mikhalovsky, "Dissociation of carbon dioxide and creation of carbon particles and films at room temperature", New Journal of Physics, 9, 321 (2007). Abstract: As fluids approach their gas-liquid critical points, the physical properties such as the specific heat and compressibility diverge due to the formation of large molecular clusters. Incident light cannot penetrate near-critical fluids because of the large clusters, a phenomenon known as critical opalescence. In this paper, we irradiate near-critical carbon dioxide (ncCO(2)), the critical temperature and pressure of which are 31.0 degrees C and 7.38MPa, with a laser beam of 213, 266, 355 and 532 nm wavelength and show that CO2 is dissociated and particles are produced when the system is set so close to the critical point that critical opalescence occurs in the case of 213 and 266 nm wavelength, whereas no particles are produced when the temperature is made to deviate from the critical value. We also apply a dc electric field to ncCO(2) during irradiation with a laser beam of 213 and 266 nm wavelength and find that particles are formed on both anode and cathode. As the intensity of the electric field increases, films are formed on the electrodes. Electron diffraction patterns and energy-dispersive x-ray, Auger electron, x-ray photoelectron and Raman spectroscopic analyses show that the particles and films are composed of amorphous carbon.

21. K. Matsumoto, C. Sato, Y. Naka, A. Kitazawa, R.L.D. Whitby, N. Shimizu, "Neurite outgrowths of neurons with neurotrophin-coated carbon nanotubes", J. Biosci. Bioeng., 103, 216-220 (2007). Abstract: Multiwalled carbon nanotubes (CNTs) coated with neurotrophin were used to regulate the differentiation and survival of neurons. Neurotrophin (nerve growth factor [NGF] or brain-derived neurotrophic factor [BDNF]) was covalently bound to CNTs modified by amino groups using a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) reagent. The CNTs coated with NGF or BDNF promoted the neurite outgrowths of neurons in the same manner as soluble NGF and soluble BDNF. By enzyme-linked immunosorbent assay (ELISA), we demonstrated that neurotrophin-coated CNTs carry neurotrophin. These results suggest that neurotrophin-coated CNTs have biological activity and stimulate the neurite outgrowths of neurons.

20. T. Fukuda, K. Ishii, S. Kurosu, R.L.D. Whitby, T. Maekawa, "Formation of clusters composed of C60 molecules via self-assembly in critical fluids", Nanotechnology, 18, 145611 (2007). Abstract: Fullerenes are promising candidates for intelligent, functional nanomaterials because of their unique mechanical, electronic and chemical properties. However, it is necessary to invent some efficient but relatively simple methods of producing structures composed of fullerenes for the development of nanomechatronic, nanoelectronic and biochemical devices and sensors. In this paper, we show that various structures such as straight fibres, networks formed by fibres, wide sheets and helical structures, which are composed of C60 molecules, are created by placing C60-crystals in critical ethane, carbon dioxide and xenon even though C60 molecules do not dissolve or disperse in the above fluids. It is supposed, judging by the intermolecular potentials between C60 and C60, between C60 and ethane, and between ethane and ethane, that C60-clusters grow with the assistance of solvent molecules, which are trapped between C60 molecules under critical conditions. This room-temperature self-assembly cluster growth process in critical fluids may open up a new methodology of forming structures built up with fullerenes without the need for any ultra-fine processing technologies.

19. A.B. Cundy, L. Hopkinson, R.L.D. Whitby. "From nano to macro: Utilising iron chemistry for contaminated land remediation and pollution control". Prog. Environ. Sci. Technol., 1, 1150-1154 (2007)

2005-2006

18. C. Gao C, Y.Z. Jin, H. Kong, R.L.D. Whitby, S.F.A. Acquah, G.Y. Chen, H.H. Qian, A. Hartschuh, S.R.P. Silva, S. Henley, P. Fearon, H.W. Kroto, D.R.M. Walton, "Polyurea-functionalized multiwalled carbon nanotubes: Synthesis, morphology, and Raman spectroscopy", J. Phy. Chem. B, 109, 11925-11932 (2005). Abstract: An in situ polycondensation approach was applied to functionalize multiwalled carbon nanotubes (MWNTs), resulting in various linear or hyperbranched polycondensed polymers [e.g., polyureas, polyurethanes, and poly(urea-urethane)-bonded carbon nanotubes]. The quantity of the grafted polymer can be easily controlled by the feed ratio of monomers. As a typical example, the polyurea-functionalized MWNTs were measured and characterized in detail. The oxidized MWNTs (MWNT-COOH) were converted into acyl chloride-functionalized MWNTs (MWNT-COCl) by reaction with neat thionyl chloride (SOCl2). MWNT-COCl was reacted with excess 1,6-diaminohexane, affording amino-functionalized MWNTs (MWNT-NH2). In the presence of MWNT-NH2, the polyurea was covalently coated onto the surfaces of the nanotube by in situ polycondensation of diisocyanate [e.g., 4,4 '-methylenebis(phenylisocyanate)] and 1,6-diaminohexane, followed by the removal of free polymer via repeated filtering and solvent washing. The coated polyurea content can be controlled to some extent by adjusting the feed ratio of the isocyanato and amino groups. The structure and morphology of the resulting nanocomposites were characterized by FTIR, NMR, Raman, confocal Raman, TEM, EDS, and SEM measurements. The polyurea-coated MWNTs showed interesting self-assembled flat or flowerlike morphologies in the solid state. The signals corresponding to that of the D and G bands of the carbon nanotubes were strongly attenuated after polyurea was chemically tethered to the MWNT surfaces. Comparative experiments showed that the grafted polymer species and structures have a strong effect on the Raman signals of polymer-functionalized MWNTs.

17. V. Stolojan, S.R.P. Silva, M.J. Goringe, R.L.D. Whitby, W.K. Hsu, D.R.M. Walton, H.W. Kroto, "Dielectric properties of WS2-coated multiwalled carbon nanotubes studied by energy-loss spectroscopic profiling", App. Phy. Lett., 86, art no. 063112 (2005). Abstract: We investigate experimentally the electronic properties of the coating for multiwalled carbon nanotubes covered in tungsten disulfide (WS2) of various thicknesses. Coatings of thicknesses between 2 and 8 monolayers (ML) are analyzed using energy-loss spectroscopic profiling (ELSP), by studying the variations in the plasmon excitations across the coated nanotube, as a function of the coating thickness. We find a change in the ELSP for coatings above 5 ML thickness, which we interpret in terms of a change in its dielectric properties.

2004

16. R.L.D. Whitby, K.S. Brigatti, I.A. Kinloch, D.P. Randall, T. Maekawa, "Novel Mg2SiO4 Structures", Chem. Comm., 21, 2396 (2004). Abstract: We describe the formation of novel, leaf-like Mg2SiO4 structures, via iodine vapour transport of magnesium onto quartz substrates.

15. R.L.D. Whitby, W.K. Hsu, Y.Q. Zhu, H.W. Kroto, D.R.M. Walton, "Novel Nanoscale Architectures: Coated Nanotubes and other Nanowires", Phil. Trans. R. Soc. Lond. A, 362, 2127-2142 (2004). Paper: Research has demonstrated that the structure and properties of a nanoscale system are inextricably linked. The advent of nanoscale research in 1991 relied upon nanoscale material production through random formation techniques, such as arc discharge, and the inherent properties and morphology of the system were therefore difficult to control. This article reviews some of the methods and ideas that have developed since the inception of nanotechnology, leading to fine control over the morphology of nanoscale systems and highlighting settle interesting nanoscale architecture. nanoscale architecture.pdf

14. Y.Z. Jin, Y.Q. Zhu, R.L.D. Whitby, N. Yao, R. Ma, P.C.P. Watts, H.W. Kroto, D.R.M. Walton, "Simple approaches to large-scale tungsten oxide nanoneedles", J. Phys. Chem. B, 108, 15572 (2004). Abstract: In this paper, a systematic study of large-scale production of highly crystalline W18O49 nanoneedles with high aspect ratios using a simple tungsten metal reacting with water at 800-1000 degreesC has been described. By altering the W source and other experimental conditions, we have generated W18O49 crystals with diverse morphologies, and needles with desired dimensions are achieved. The quality nanoneedles provide ideal samples for further property investigations. Possible growth mechanisms are discussed.

2003

13. R.L.D. Whitby, W.K. Hsu, C.B. Boothroyd, K.S. Brigatti, H.W. Kroto, D.R.M. Walton," WS2 layer formation on multi-walled carbon nanotubes" Appl. Phys. A-Mater. Sci. Process., 76, 527 (2003). Abstract: Time-dependent powder X-ray-diftraction analyses reveal that the conversion Of WO3 into WS2 on carbon nanotube surfaces in the presence of H2S is a one-step process. The W layers grow simultaneously along the tube in the radial and axial directions. Paper

12. R.L.D. Whitby, W.K. Hsu, C.B. Boothroyd, H.W. Kroto, D.R.M. Walton, "WS2/C Nanocomposites Reviewed", New Diamond and Frontier Carbon Technology, 13, 7 (2003). Abstract: Whilst generating nanotubes with modified material properties, multiwalled carbon nanotubes (MWCNs) were found to be capable of acting as templates for WS2 nanotube growth. The MWCNs, coated with WO, by heating a mixture of MWCNs and a tungsten oxide precursor, i.e., H2WO4 were then sulphidised at 900degreesC in order to convert the WO, into WS2 layers.

11. V. Stolojan, M.J. Coringe, S.R.P. Silva, R.L.D. Whitby, D.R.M. Walton, W.K. Hsu, H.W. Kroto, "Spatially resolved analysis of the electronic properties of WS2-coated carbon nanotubes using EELS in a TEM", Proceedings Seventh Applied Diamond Conference, Third Frontier Carbon Technology, A35, (2003)

2002

10. R.L.D. Whitby, W.K. Hsu, H. W. Kroto, D.R.M. Walton, "Tungsten disulphide coated multi-walled carbon nanotubes, review of the synthesis and characterisation", Physical Sciences, Engineering and Technology -Recent Research Developments in Applied Physics, Vol. 5 (2002) Part II. Abstract: The Sussex Nanoscience & Nanotechnology Centre has developed a novel method for the creating tungsten disulphide (WS2) nanotubes on the surface of multi-walled carbon nanotubes (MWCNs). The procedure allows for part control of the deposition mechanism, whereby it is now possible to generate single-walled WS2 nanotube coatings for MWCNs.

9. R.L.D. Whitby, W.K. Hsu, T.H. Lee, C.B. Boothroyd, H.W. Kroto, D.R.M. Walton, "Complex WS2 nanostructures", Chem. Phys. Lett., 359, 68 (2002). Abstract: A range of elegant tubular and conical nanostructures has been created by template growth of (WS2)(n) layers on the surfaces of single-walled carbon nanotube bundles. The structures exhibit remarkably perfect straight segments together with interesting complexities at the intersections, which are discussed here in detail in order to enhance understanding of the structural features governing tube growth. Paper

8. R.L.D. Whitby, W.K. Hsu, H.W. Kroto, D.R.M. Walton, "Conversion of amorphous WO3-x into WS2 nanotubes", Phys. Chem. Chem. Phys., 4, 3938 (2002). Abstract: Removal of the carbon template from WS2-coated multi-walled carbon nanotube ( MWCN) composites, produced WS2 nanotubes with intriguing microstructures. TEM characterisation shows that the intermediate phases of amorphous WO3-x-WS2 nanostructures, support the previously proposed growth model for WS2 nanotubes on MWCNs. Paper

7. R.L.D. Whitby, W.K. Hsu, C.B. Boothroyd, H.W. Kroto, D.R.M. Walton, "WS2 coated MWCNs", Chem. Phys. Lett., 359, 121 (2002). Abstract: Multi-walled carbon nanotubes (MWCNs), coated with ordered WS2 mono- or multi-layers, are generated by pyrolysing H2S/N-2 over MWCNs thinly coated with WO3. High-resolution transmission electron microscopy (HRTEM) reveals the presence of hexagonal WS2 arrays in the tube surface, consistent with the WS, simulated structure. Paper

6. R.L.D. Whitby, W.K. Hsu, P.K. Fearon, N.C. Billingham, I. Maurin, H.W. Kroto, D.R.M. Walton, C.B. Boothroyd, S. Firth, R.J.H. Clark, D. Collison, "Tungsten disulphide coated multi-walled carbon nanotubes", Chem. Mat., 14, 2209 (2002). Abstract: Novel binary-phase WS2-C nanotubes were generated by pyrolyzing WO3-coated multiwalled carbon nanotubes in an H2S/N-2 atmosphere at 900 degreesC. The WS2 coating acts as an anti-oxidizing agent. Paper

5. R.L.D. Whitby, W.K. Hsu, C.B. Boothroyd, P.K. Fearon, H.W. Kroto, D.R.M. Walton, "Binary Phase of Layered Nanotubes", Materials Research Society, Making functional materials with nanotubes, 706, Z7.6.1 (2002)

4. N. Grobert, W.K. Hsu, H.W. Kroto, M. Mayne, M. Terrones, P.C.P. Watts, R.L.D. Whitby, D.R.M. Walton, Y.Q. Zhu, "Novel nanostructures: from metal-filled carbon nanotubes to MgO nanoferns", Perspectives Fullerene Nanotech., 11-19 (2002). Abstract: Recently, numerous advances have been achieved by the fullerene/nanotube team at Sussex. Formerly, arc discharge techniques provided a unique method for generating fullerenes and carbon nanotubes. However, the yields and dimensional uniformity of these materials were not controllable. We have made significant advances in this area by pyrolysis of selected organic precursors in order to generate: (a) aligned nanotube bundles of uniform length and diameter; (b) metal nanowires using benzene-based aerosols in conjunction with metallocenes; (c) CNx nanostructures. High-temperature methods have also been employed to produce (d) fern-like MgO nanostructures using MgO and Co mixtures. Finally, these novel materials are predicted to exhibit extraordinary physical and chemical properties and may thus prove useful, i.e. in the manufacture of (superstrong) composite materials and novel electronic or optical devices (e.g. field emission sources, ultra-thin TV displays, etc.)

2001

3. R.L.D. Whitby, W.K. Hsu, C.B. Boothroyd, P.K. Fearon, H.W. Kroto, D.R.M. Walton, "Tungsten disulphide sheathed carbon nanotubes", ChemPhysChem, 2, 620 (2001). (Front Cover) Paper

2. R.L.D. Whitby, W.K. Hsu, C.B. Boothroyd, P.C.P. Watts, H.W. Kroto, D.R.M. Walton, "WS2-coated single-wall carbon nanotube bundles", Appl. Phys. Lett., 79, 4574 (2001). Abstract : Single-walled carbon nanotubes (SWCNs) encapsulated in multiwalled WS2 nanotubes are produced by pyrolyzing a mixture of WO3-x and SWCNs in N-2/H2S atmosphere. Paper

1. T. Drewello, T. Brown, R. Whitby, M.A. Trikoupis, J.K. Terlouw, P.R. Birkett, "Laser-induced aza-heterofullerene formation", Abstr. Pap. Am. Chem. Soc., 221, 201 (2001).