Prof. Karl S. Coleman
(email at email@example.com)
The group’s research interests are in the field of nanotechnology. Nanotechnology is the science of creating structures or materials on a nanometre (one millionth of a millimetre) scale. Interestingly, the fundamental physical and chemical properties of materials are altered as they are decreased to the nanometre scale. Therefore, nanostructured materials offer great potential in the development of new electronic devices, bio-sensors and high strength composites. Our work in this area involves, amongst others, the synthesis and chemistry of graphene and carbon nanotubes as well as nanolithography (the patterning of surfaces).
Synthetic procedures within the group often involve sensitive materials which are handled using inert atmosphere glove-box or Schlenk line techniques. As well as making use of the more routine analytical techniques to characterise the materials, such as NMR spectroscopy and mass spectrometry, the group makes extensive use of scanning probe microscopy (SPM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). An outline of some of our interests are given below.
Chemistry of Carbon Nanotubes
Single-walled carbon nanotubes (SWNTs) have attracted interest and excitement across a broad spectrum of sciences from engineering, materials, chemistry, biology to medicine. Single-walled carbon nanotubes can simply be thought of as a rolled up single sheet of graphite joined at the edges. They are immensely strong with a strength similar to that of steel and can be metallic or semi-conducting depending on their structure. Such impressive mechanical and electronic properties have opened the way for the development of new technologies. However, many possible applications of nanotubes, from use as components in electronics to chemical and biological sensors, can only be realized through chemical control.
We are currently investigating methods of chemically functionalising the carbon nanotubes to:
- improve dispersion in aqueous and non-aqueous solvents.
- control their electronic properties for nanoelectronics.
- enhance their interaction with a range of polymer matrices to form new generation nanocomposites.
- improve and tailor the bio- compatibility of the nanotube surface to selectively adsorb biological materials for nanoscale biosensors.
- translocate into cells for imaging and drug delivery.
Graphene is single layer of carbon atoms arranged in a continuous honeycomb network and is the latest addition to the nanocarbon family. This 2D nanostructure, best visualised as single layer of graphite, shares the exciting properties of other carbon nanomaterials. Like carbon nanotubes, which can be considered to be a rolled up sheet of graphene, the material has exceptional electrical, thermal and mechanical properties. As a result various applications in materials science including polymer nanocomposites, energy storage materials, transparent thin film electrodes and nanoelectronic components have been envisaged. It has even been suggested that graphene could outperform carbon nanotubes in some of these applications.
One of the problems in graphene research is the availability of the material and the difficulties involved with its synthesis. These issues need to be solved if the applications listed above are to be made viable. Our interests lie in the synthesis of graphene using a variety of methodologies that are scalable and selective for the formation of graphene or few-layer graphene.
We have formed a University spinout company Durham Graphene Science Ltd (http://www.durhamgraphene.com) to commercialise some aspects of this work.
Figure: Filtered high-resolution transmission electron micrograph of a graphene sheet produced in our laboratory.
Nano- Patterned Functional Surfaces
In recent years the generation of nano-patterned surfaces has attracted considerable attention. The ability to selectively engineer chemical composition and structure on such a small scale is of great potential application, particularly in the fields of nanoelectronics, biotechnology and sensing. Methods such as microcontact printing, mechanical spotting and nanoimprint lithography have proved useful in the development and fabrication of DNA, protein and glyco arrays. More recently, nanolithography methods, based on scanning probe technology [atomic force microscopy (AFM), scanning tunnelling microscopy (STM) and scanning near-field optical microscopy (SNOM)] have been developed, taking advantage of the nanometre sized dimensions of the probes and strong localised tip-surface interactions.
We are currently investigating methods to:
- generate chemically distinct and spatially controlled nanometre scale patterns in multi-layer films using nano-displacement methodology.
- use chemically modified AFM probes to induce spatially controlled surface reactions.
- use chemically distinct patterned regions to selectively adsorb or bind biomolecules.
- use patterned region as a template for directed nanoparticle assembly.
Nanodisplacement strategy to induce site specific changes in a multilayer film generating a hydrophobic pocket capable of selectively binding biomolecules.
- Directly observed covalent coupling of quantum dots to single-wall carbon nanotubes. B.R. Azamian, K. S. Coleman, J. J. Davis, N. Hanson, M. L. H. Green, Chemical Communications, 2002, 366-367.
- Functionalization of single walled carbon nanotubes via the bingel reaction. K. S. Coleman, S. R. Bailey, S. Fogden, M. L. H. Green, Journal of the American Chemical Society, 2003, 125, 8722-8723.
- Chemical and bio-chemical sensing with modified single walled carbon nanotubes. J.J. Davis, K. S. Coleman, B. R. Azamian, C. B. Bagshaw, M. L. H. Green, Chemistry a European Journal, 2003, 9, 3732-3739.
- Spatially resolved suzuki coupling reaction initiated and controlled using a catalytic AFM Probe. J. J. Davis, K. S. Coleman, K. L. Busuttil, C. B. Bagshaw. Journal of the American Chemical Society, 2005, 127, 13082-13083.
- Iodination of single-walled carbon nanotubes. K. S. Coleman, A. K. Chakraborty, S. R. Bailey, J. Sloan, M. Alexander. Chemistry of Materials 2007, 19, 1076-1081.
- A new route to the production and nanoscale patterning of highly smooth, ultrathin zirconium oxide films. S. M. D. Watson, K. S. Coleman, A. K. Chakraborty. ACS Nano 2008, 2, 643-650.
- A facile, solvent-free, noncovalent, and nondisruptive route to functionalize single-wall carbon nanotubes using tertiary phosphines. A. Suri, A. K. Chakraborty, K. S. Coleman. Chemistry of Materials 2008, 20, 1705-1709.
- Fluorescent single-walled carbon nanotubes following the 1,3-dipolar cycloaddition of pyridinium ylides. M. K. Bayazit, K. S. Coleman. Journal of the American Chemical Society 2009, 131, 10670-10676.
- Pyridine-functionalized single-Walled carbon nanotubes as gelators for poly(acrylic acid) hydrogels. M. K. Bayazit, L. S. Clarke, N. Clarke, K. S. Coleman, Journal of the American Chemical Society 2010, 132, 15814.
- Simple and scalable route for the 'bottom-up' synthesis of few-layer graphene platelets and thin films. C. R. Herron, R. S. Edwards, K. S. Coleman, B. Mendis, Journal of Materials Chemistry 2011, DOI: 10.1039/C0JM03437A