Dr. Jamal Hassan obtained his Ph.D. degree in Physics , Nuclear Magnetic Resonance, from the University of Waterloo, Ontario, Canada in 2007. Dr. Hassan’s research interest is studying water dynamics and behavior in nano-confinements including carbon nanotubes. He uses different NMR experimental techniques to study water behavior inside hydrophobic, silica-based, and hydrophobic, carbon-based, materials.
Several theoretical studies using molecular dynamics MD simulations showed an enhancement of water dynamics inside hydrophobic channels and reported a peak of the liquid self-diffusion coefficient at certain carbon nanotube sizes. However, experimental confirmation of this size-dependent liquid-dynamics was so far lacking. We use 2D NMR spectroscopy diffusion –relaxation 2D D-T2, relaxation-relaxation 2D T1-T2 measurements as well as MD simulations of water in carbon nanotubes of different sizes to investigate water diffusion in thses systems. These NMR methods provide unique ways to distinguish water in the interior of CNTs from bulk water and water adsorbed on the external surface of the CNTs. Experiments show that water inside CNTs is further resolved into two components with different diffusion coefficient (D) values; water in proximity with the CNT walls, and water along the CNT axis.