Theresa Hedderman BA (Mod.) PhD

Email: theresa.hedderman@dit.ie

Graduated with B.A. (mod.) (Hons) in Chemistry in 1999 from Trinity College Dublin. I undertook a PhD on a part-time basis in January 2001 and graduated in 2006. The research explored novel materials, carbon fibers. I am currently supervising a PhD project titled "A study of structure-property relationship between single wall carbon nanotubes and polycyclic aromatic hydrocarbons" by Sourabhi .Debnath.

Research Interests:

My current research interests invlove investigating the potential of carbon fibers to purify contaminated water.

The availability of potable water is a global crisis. Carbon materials have shown potential to treat contaminated water. Research has shown that carbon materials such as charcoal and activated carbon materials have been used to treat waste water. This project proposes to introduce nanocarbon fibers known as single walled carbon nanotube, multi walled carbon nanotubes and fullerenes to treat contaminated water in the hope of producing potable water. It is proposed that the nanofilter will allow steps in the current filtration method to be bypassed thereby increasing the amount of potable water available in a shorter space of time with no additional energy requirement which would be very desirable given the current global energy crisis. The proposed organic nanofilter will be assessed via spectroscopic and microscopic techniques along with a host of other analytical techniques such as chromatography and ICP on both fresh and salt water samples. If successful not only will Ireland’s but the world’s potable water crisis will be substantially alleviated by the new development in technology. The proposed end result of the project is a commercially viable filter. The project as a whole will contribute greatly to enhancing and developing the environment and the economy in a green manner through increased knowledge, techniques and expertise in environmental science.

PhD Thesis Title:

Solubilisation, Purification and Processing of Single Walled Carbon Nanotubes Using Organic Molecules.

Thesis overview:

In the research, the solubilisation, purification and bundle dispersion of single walled carbon nanotubes (SWNTs) on interaction with the polycyclic aromatic hydrocarbons (PAHs), anthracene and p-terphenyl were explored. The investigations were performed in toluene due to its poor affinity for the retention of SWNTs. Thus this solvent acted as a good indicator for improvements in the solubility of the SWNTs due to the presence of the PAHs. The hydrocarbons anthracene and p-terphenyl were chosen because like toluene they were non polar and therefore were highly soluble in toluene and with their simple structure it was proposed that the PAH’s may exhibit molecular recognition of SWNTs with a similar backbone structure to that of the hydrocarbon. 

The study began with the exploration of the interaction between the SWNTs in an untreated sample and the PAHs, and results revealed enhanced solubility of the SWNTs in toluene and subsequently the purification of the SWNT sample. Interaction between the PAHs and the SWNTs drew the SWNTs into solution allowing all side products to precipitate out. The composite solutions were stable suspension of finely dispersed SWNTs with no evidence of SWNT precipitation observed in over a five year period. This observation indicated an enhanced stability of the SWNTs in solutions due to an interaction with the PAH molecules and this observation is supported by Raman and fluorescence spectroscopic studies which were presented in this thesis. Both anthracene and p-terphenyl map via a π – π interaction to the SWNT backbone with strong indications of structural selectivity between the SWNT surfaces and PAHs.

The literature is scarce with regard to the interaction between organic molecules and SWNTs. In this research an investigation into the interaction that occurs between PAHs and SWNTs was conducted. The interactions and debundling of SWNTs over a broad concentration range were probed through spectroscopic methods including fluorescence and Raman. Fluorescence concentration dependence studies defined the concentration range where aggregated PAHs and isolated PAHs exist. A fluorescence model based on the fraction of free hydrocarbons is used to indicate the concentration range where debundled and bundled SWNTs and PAHs were interacting with atomic force microscopic (AFM) studies supporting the results.  AFM is used to obtain a topographic profile of the SWNTs at a range of concentrations to image the debundling of SWNTs with decreasing concentration. The fluorescence model also allows the calculation of a binding energy between the SWNTs and PAHs at low concentrations. The binding energy determined is further supported by alternative theoretical models and the results obtained correlate well. Raman studies support fluorescence and AFM studies with regard to the interaction and debundling of SWNTs and the Raman radial breathing modes (RBMs) were probed to investigate selective interaction of the PAH molecules at low concentrations and results reveal a degree of selective interaction.

List of publications:

Refereed Journals

Hedderman, T.G., Shanahan, A.E., Mostaert, A., Byrne H.J., (2009), “The Bundle Dispersion of SWCNT on Interaction with p-Terphenyl”, New Carbon Materials, vol. 4, no.1, 73-81.

Debnath, S., Cheng, Q., Hedderman, T.G., Byrne H.J., (2008), “A Study of the Interaction between Single-Walled Carbon Nanotubes and Polycyclic Aromatic Hydrocarbons: Toward Structure-Property Relationships”, J. Phys. Chem. C., 112, 10418-10422.

Hedderman, T.G., Keogh, S.M., Chambers, G., Byrne H.J., (2006), “In-depth study into the interaction of single walled carbon nanotubes with anthracene and p-terphenyl”, J. Phys. Chem. B., 110, 3895-3901.

Hedderman, T.G., Keogh, S.M., Chambers, G., Byrne H.J., (2004), “Solubilisation of SWNT with organic dye molecules”, J. Phys. Chem. B., 108, 18860-18865.

Keogh S.M., Hedderman T.G., Lynch P.,Byrne H.J., (2006), “Bundling and diameter selectivity in HiPco SWNTs poly (p-phenylene vinylene-co-2, 5 dioctyloxy-m-pheneylene) composites”, J. Phys. Chem. B., 110, 19369-19374.

Keogh S.M., Hedderman T.G., Ruther, M.G., Lyng. F.M., Gregan E., Farrell G., Chambers G., Byrne H.J., (2005), “Temperature- induced nucleation of poly(p-phenylene vinylene-co-2,5-dioctyloxy-m-phenylene vinylene) crystallization by HiPco SWNT”, J. Phys. Chem. B., 109, 5600–5607.

Keogh S.M., Hedderman T.G., Gregan E., Farrell G., Mc Namara M., Ruether M., Chambers G., Byrne H.J., (2005), “Temperature dependent studies of HiPco SWNT and polymer composites”, Journal of Synthetic Metals, 154, 197-201.

Keogh S.M., Hedderman T.G., Gregan E., Farrell G., Chambers G., Byrne H.J., (2004), “Spectroscopic analysis of single-walled carbon nanotubes and semiconjugated polymer composites”, J. Phys. Chem. B., 108, 6233–6241.

Conference Proceedings

Debnath, S., Cheng, Q., Hedderman, T.G., Byrne, H.J.,  (2008), “An experimental study of the interaction between single walled carbon nanotubes and polycyclic aromatic hydrocarbons”, Proceedings of the International Winterschool of the Electronic Properties of Novel Materials (IWEPNM), Physica Status Solidi, (reference number JOT 5188).

Hedderman, T.G., O’Neill, L., Maguire, A., Keogh, S.M., Gregan, E., McCarthy, B., Dalton, A.B., Chambers, G., Byrne, H.J., (2005), “Spectroscopic analysis of the interaction of SWNT with simple organic molecules”, Proceedings of Opto Ireland, The International Society for Optical Engineering, Society of Photographic Instrumentation Engineers (SPIE), 5826, 12-24.

Hedderman T.G., O’Neill, L., Maguire, A., Keogh, S.M., Gregan, E., Chambers, G., Byrne, H.J., (2003), “Interaction of SWNT with simple dye molecules”, Proceedings of the International Winterschool of the Electronic Properties of Novel Materials (IWEPNM), 685, 261-264.

Hedderman, T.G., O’Neill, L., Maguire, A., Keogh, S.M., Gregan, E., McCarthy, B., Dalton, A.B., Chambers, G., Byrne, H.J., (2002), “The use of single walled carbon nanotubes as templates for organic molecules”, Proceedings of the International Winterschool of the Electronic Properties of Novel Materials (IWEPNM), 633, 610-613.

Hedderman, T.G., O’Neill, L., Maguire, A., Keogh, S.M., Gregan, E., McCarthy, B., Dalton, A.B., Chambers, G., Byrne, H.J., (2002), “Single walled carbon nanotubes as templates for organic molecules”, Proceedings of Opto Ireland, The International Society for Optical Engineering, Society of Photographic Instrumentation Engineers (SPIE), 4876, 696-703.

Keogh, S.M., Maguire, A., Hedderman, T.G., Gregan, E., Chambers, G., Byrne, H.J., (2005), “Fluorescence concentration studies of HiPco SWNT and semi-conjugated polymers”, Proceedings of Opto Ireland, The International Society for Optical Engineering, Society of Photographic Instrumentation Engineers (SPIE), 5826, 67-74.

Keogh, S.M., Hedderman, T.G., Farrell, G.F., Ruether, M., Gregan, E., McNamara, M., Chambers, G., Byrne, H.J., (2005), “Temperature dependent studies of HiPco SWNT and polymer composites”, International Conference of Synthetic Metals (ICSM), 154, 197-

207.

Keogh, S.M., Maguire, A., Hedderman, T.G., Gregan, E., Chambers, G., Byrne, H.J., (2003), “Physical interaction between HiPco SWNT’s and semi-conjugated polymers”, Proceedings of the International Winterschool of the Electronic Properties of Novel Materials (IWEPNM), 685, 265-268.

Keogh, S.M., Maguire, A., Hedderman, T.G., Gregan, E., Chambers, G., Byrne, H.J., (2002), “Physical interaction between HiPco SWNT’s and Semi-conjugated polymers”, Proceedings of Opto Ireland, The International Society for Optical Engineering, Society of Photographic Instrumentation Engineers (SPIE), 4876, 723-731.

Keogh, S.M., Maguire, A., Hedderman, T.G., Gregan, E., McCarthy, B., Dalton, A.B., Chambers, G., Byrne, H.J., (2002), “Physical interaction between HiPco SWNT’s and semi-conjugated polymers”, Proceedings of the International Winterschool of the Electronic Properties of Novel Materials (IWEPNM), 633, 570-573.

Gregan, E., Keogh, S.M., Hedderman, T.G., Chambers, G., Byrne, H.J., (2005), “Use of Raman in the investigation of debundling of single walled carbon nanotubes”, Proceedings of Opto Ireland, The International Society for Optical Engineering, Society of Photographic Instrumentation Engineers (SPIE), 5826, 56-66.

Gregan, E., Keogh, S.M., Maguire, A., Hedderman, T.G., O’Neill, L., Chambers G., Byrne, H.J., (2004), “Purification and isolation of SWNT”, Carbon, 42, 1031-1035.

Gregan, E., Keogh, S.M., Hedderman, T.G., Chambers, G., Byrne, H.J., (2002), “Stokes/anti-Stokes Raman spectroscopy of HiPco single walled carbon nanotubes”, Proceedings of Opto Ireland, The International Society for Optical Engineering, Society of Photographic Instrumentation Engineers (SPIE), 4876, 1149-1157.

Gregan, E., Keogh, S.M., Hedderman, T.G., McCarthy, B., Farrell, G., Chambers, G., Byrne, H.J., (2002), “Stokes/anti-Stokes Raman spectroscopy of HiPco single walled carbon nanotubes”, Proceedings of the International Winterschool of the Electronic Properties of Novel Materials (IWEPNM), 633, 294-297.

Oral presentations

“Spectroscopic analysis of the interaction of polycyclic aromatic hydrocarbons with SWNT”, International Conference of Synthetic Metals (ICSM), Trinity College, Dublin, July 2006.

“Spectroscopic analysis of the interaction of SWNT with simple organic molecules”, Opto Ireland, Society of Photographic Instrumentation Engineers (SPIE) conference, Royal Dublin Society, Dublin, April 2005.

Poster presentations

“The analysis of the interaction of SWNT with terphenyl” International Conference of Synthetic Metals (ICSM), Trinity College, Dublin, July 2006.

“Carbon nanotubes as templates for organic molecules”, International Winterschool of the Electronic Properties of Novel Materials (IWEPNM), Kirchberg, Austria, March, 2003.

“Single walled carbon nanotubes as templates for organic molecules”, Opto Ireland, Society of Photographic Instrumentation Engineers (SPIE) conference, Galway, September 2002.

“Carbon nanotubes as templates for organic molecules”, International Winterschool of the Electronic Properties of Novel Materials (IWEPNM), Kirchberg, Austria, March, 2002.