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MSc or PhD positions are available in my group for 2011/2012. 4th year undergraduate students interested in completing Honours research projects in my lab are always welcome. Please contact if interested.
Materials, Electrochemistry and Analytical Chemistry
Surface modifications have emerged as powerful tools in the field of materials science and nanotechnology. Recognizing the increasing role of molecular electronic devices and sensors, different strategies have been employed to immobilize organic or bioorganic molecules onto the surface of electrodes. The covalent binding of alkane thiols to Au(111) carrying target molecules has been widely used to form self-assembled monolayers (SAMs). Other electrode surfaces have also been tested. However, the lack of reproducibility and reliability are primary drawbacks. Moreover, the stability of the surface on air exposure and organic solvents is a major problem. Another alternative has been developed through derivatization of semi-conducting surfaces such as Si(111) via alkyl chains substituted by electro-polymerizable π-aromatic compounds such as thiophene. The presence of the polythiophene layers at the Si(111) surface prevents the penetration of metal and organic solvents that can potentially damage the Si surface.
The improvement of the immobilization techniques and consequently the organic- and bioorganic- based biosensors depends on the control of the immobilization environment. To overcome different problems associated with the adsorption of organic or bioorganic molecules at the surface of the electrodes, we propose a convenient approach, which aims at protecting the electrode with a conducting π-conjugated polymer and incorporates the target molecule onto the surface of the polymer layer and not directly onto the electrode. The choice of this conducting layer is essential to the process. It should be stable, easy to functionalize, highly conducting and have excellent adhesive properties. Polythiophenes, polypyrroles and polyfurans are potential candidates for these electrode protection purposes. The success of the adsorption of a designated organic or bioorganic molecule onto the surface of the electrode relies upon control and closer understanding of the phenomena occurring at the interfaces. The interactions involving Metal/polymer and polymer-target molecules generate important physico-chemical data, which can be monitored to enhance the success of the immobilization process.
We are interested in: 1- Studying the interaction occurring at the surface of the electrode or of the polymer and ii) the adsorption of organic/bioorganic moieties as a single molecule onto the surface of the polymer. 2- Developing microchip devices which can be used as electrochemical, optical and biological sensors. 3- Using green chemistry for the synthesis of new heterocyclic compounds necessary to build materials that can be used in electro-chromic devices.
Selected publications
McTiernan, C.D., Omri, K., and Chahma, M.
Chiral conducting surfaces via electrochemical oxidation of L-leucine-oligothiophenes.
J. Org. Chem. 2010, 75 (18): 6096-103.
Myles, D. J. T.; Chahma, M.; Hicks, R. G. “ Synthesis and electronic structure investigations of end-caped of bis(oligothienyl) sulfides”.
Can. J. Chem. 2008, 86, 982-991.
Chahma, M.; Gilroy, J.; Hicks, R. G. “Linear and branched electroactive polymers based on ethylenedioxythiophene – triarylamine conjugats”.
J. Mater. Chem. 2007, 17, 4768-4771.
Chahma, M.; Macnamara, K.; van der Est A.; Alberola, A.; Polo, V.; Pilkington, M. “Synthesis and characterization of a TTF-pi-verdazyl radical A new building block for conducting and/or magnetic systems”.
New J. Chem. 2007, 31, 1973-1978.
Chahma, M.; Hassan, N.; Alberola, A.; Stoeckli-Evans, H.; Pilkington, M. “Preparation and coordination complex of the first imine bridged TTF-Pyridine donor ligand”.
Inorg. Chem. 2007, 46, 3807-3809.
Tanko, J. M.; Li, X.; Chahma, M.; Jackson, W.; Spencer, J. N. “Cyclopropyl conjugation and ketyl anions: When do things begin to fall apart?”.
J. Am. Chem. Soc. 2007, 129, 4181-4192.
C. Ji, M. Ahmida, M. Chahma, A. Houmam. “Radical/ion pair formation in the electrochemical reduction of arene sulfenyl chlorides”.
J. Am. Chem. Soc. 2006, 128, 15423-15431.
M. Chahma, M. Pilkington, X. Wang, A.Van der Est. “Synthesis and characterization of a new family of spin bearing TTF ligands ”.
J. Org. Chem. 2006, 17, 2750-2755.
M. Chahma*. “Synthesis and characterization of new poly(thiophene sulfides) via chemically initiated oxidative polymerization methods”.
Synth. Metals. 2005, 155, 474-479.
M. Chahma, D. J. T. Myles, R. G. Hicks. “Synthesis and electropolymerization behavior of bis(oligothienyl) sulfides. Generation of heteroaromatic poly(p-phenylene sulfide) analogs”.
Chem. Mater. 2005, 17, 2672-2678.
M. Chahma, X. Li, J. P. Phillips, P. Schwartz, L. E. Brammer, Y. Wang, J. M. Tanko. “Activation/driving force relationships for cyclopropylcarbinyl homoallyl-type rearrangements of radical anions”.
J. Phys. Chem. A 2005, 109, 3372-3382.
M. Chahma*, J. S. Lee, H-B. Kraatz. “Fc-ssDNA conjugate: Electrochemical properties in borate buffer and adsorption on gold electrode surfaces”.
J. Electroanal. Chem. 2004, 567, 283-287.
M. Chahma*, C. Combellas, A. Thiébault. “Synthesis of new nitrogen heterocyclic organic salts”.
Synthesis 2004, 4, 517-520.
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