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SCIENCE TECHNOLOGY Professor of Physics Department of Physics Tel 868 662 2002 ext. 82591 E-mail satpal.sekhonsta.uwi.edu PROF. SATPAL SINGH SEKHON The research work of my group is related to various types of materi- als polymers ionic liquids composites membranes metal free catalysts nanomaterials for energy devices. A brief description of the research work in each area and some representative publica- tions are listed below Carbon Nanomaterials in collaboration with Sangmyung UniversityCheonan CampusRepublic of Korea Carbon nanomaterials multiwall carbon nanotubes and graphene have been developed for use in fuel cells.Graphene was functionalized with nitrogen containing polyelectrolyte PDDA and found to be suitable for use as a metal-free catalyst for the oxygen reduction reaction in fuel cells. The multiwall carbon nanotubes functionalized with hydrogen-containing groups can find applications in fuel cell membranes and thus MWCNTs were functionalized with different proton-containing groups using various single- and double-step chemical routes. As multiwall carbon nanotubes generally exist in bundles in the pristine form so they were dispersed by using a surfactant Triton X-100 prior to their functionalization. The CNTs functionalized with COOH groups show better functionalization.The maximum functionaliza- tion with -SO3H groups was achieved by a double-step chemical routewhereas the maximum functionalization with -PO3H2 groups was achieved with phosphoric acid. The incorporation of CNTs functionalized with the -SO3H and -PO3H2 groups in sulfonated polymers can be used to develop high-temperature fuel cell membranes. Fuel Cells in collaboration with Korea Institute of Energy ResearchDaejeonRepublic of Korea Inasmuch as fossil fuels are limited fuel cells are proposed as future power sources which are environment friendly and green in nature with no toxic emissions. Due to problems of CO poisoning and methanol-crossover with the membranes currently used in fuel cells there is need to develop alternate materials. We developed water-free proton conducting fuel cell membranes containing ionic liquids EMIBF4 EMIPF6. The effect of replacing water with ionic liquids in polymeric membranes based on recast Nafion and sulfonated poly aryl ether ketone SPAEK-6F on the morphology and the formation of ionic aggregates was studied using small-angle X-ray scattering SAXS. The membranes containing ionic liquids have ionic conductivity 0.01 Scm-1 above 100oC under ambient humidity have good mechanical strength and are thermally stable up to 300o C and are hence suitable for use in polymer electrolyte fuel cells PEFCs at medium temperatures 100-200o C under non-humid conditions. The evolution of the ionomer peak with an increase in the concentration of the ionic liquid was studied for the first time for recast Nafion membranes containing an ionic liquid by SAXS.It was found that sulfonated polymers with distinct hydrophobic and hydrophilic parts favour the formation of ionic clusters along with higher ionic conductivity.The correlation between ionic conductiv- ity and the cluster morphology can be quite helpful in designing new water-free proton-conducting membranes for fuel cells. Fluoride Ion Conductors in collaboration with Hiroshima Universityand Nihon UniversityJapan The ionic diffusional motion of various fluoride ion conductors containing ionic liquids ILs studied by Solid State NMR and DTA simultaneously has been found to be strongly correlated with the ionic conductivity. The ionic liquid containing an acidic counter- anion showed a high value of ionic conductivity 3.37 10-2 Scm-1 at 150C. The onset of ion diffusional motion in electrolytes contain- ing ILs takes place at the same temperatures at which line narrow- ing was observed in the NMR spectra and corresponds to the glass transition and melting temperatures. The transformation of the polymer from the semi-crystalline to amorphous phase at the melting temperature observed by XRD was also correlated with the ionic conductivity results. Nanoclusters of III-V Compound Semiconductors in collaboration with Dr.Vijay Kumar FoundationIndia The nanoparticles of III-Vn IIIAlGaInVNPSbn 1-150 are very important materials for various optoelectronic applications and have been studied from first-principles calculations.Our results show that in the small size range AlP13 and AlAs13 are magic. However in the intermediate size range GaP32 and GaAs32 are magic with AlP13 and GaP32 being more exceptional. The magic behaviour of III-V nanoparticles is material-specific and the bonding character also plays an important role. The GaN and AlN nanoparticles favour inorganic fullerene analogs of empty-cage structures with sizes of at least up to around 34 and they may continue to be so even for some larger sizes due to stronger sp2 bonding while for InN32 a filled-cage isomer becomes lower in energy.The InN nanoparticles were found to develop 3D structures faster as the size grows compared to AlN and GaN. We have also shown from first-principles calculations that 118