About Dr Ahmad Jabbarzadeh

Dr Ahmad Jabbarzadeh is an internationally recognized molecular rheologist (science of flow and deformation of materials) and tribologist (science of friction and lubrication) whose research mainly deals with studying the properties of complex materials by advanced computational techniques at micro and nano scales.

Ahmad's work aims to understand material properties, flow and phenomena at nano-scale.

Dr. Jabbarzadeh has significant experience in molecular simulations of simple and complex fluids in bulk and complex geometries. His contributions include development of a domain decomposition message-passing parallel algorithm for molecular dynamics simulation of liquids in nano-scale geometries, development of parallel algorithm for simulation of branched molecules, use of molecular dynamics to investigate the ultrathin-film nanorheology and nanotribology, explaining the relationship between the boundary condition of fluid flow next to a solid surface and surface roughness, energy and molecular size. Using molecular level simulations of model lubricants he has explained the high load capacity of molecularly thin lubricant films in boundary lubrication regime through their non-Newtonian behaviour and high first normal stress differences. He also found correlation between the boundary conditions and many properties of the confining surface and molecular size of the confined film and also wall-fluid interaction energy. His simulations with sinusoidal shaped walls established the effect of roughness and its characteristics on the behaviour and boundary conditions in shear flow. One of the advantages of his work is to design material at molecular level with desired properties. He has done one of the first simulations to study the effects of molecular degree of branching on rheological properties under shear for polymers and lubricants. His most recent contributions have explained why confined films of linear alkanes (main constituent s of mineral oil) less than a few molecular diameters thick exhibit extremely high viscosity. In these studies the structural origins of transition to rigidity, and the role of confining surfaces roughness, in-plane order and relative orientation have been unravelled. These works have been reported in several papers including papers in the prestigious journal Physical Review Letters and a feature article in Journal of Physical Chemistry B. Dr. Jabbarzadeh together with other members of rheology group is involved in collaborative research with Australian Cooperative Research Centre for Polymers. Using molecular dynamics simulation he investigates polymer crystallization under various conditions.

Selected publications

Chapter in Books:  1. * A. Jabbarzadeh and R. I. Tanner, “Molecular dynamics simulation and its application in nano-rheology” Rheology Reviews, (Ed. D. M. Binding and K. Walters) 165-216 (2006).Journal Papers:  2. *A. Jabbarzadeh, J. D. Atkinson and R. I. Tanner, “Parallel Simulation of Shear Flow of Polymers Between Structured Walls By Molecular Dynamics Simulation on PVM,” Computer Physics Communications 107 (1997) 123-136.  3. *A. Jabbarzadeh, J. D. Atkinson and R. I. Tanner, “Nanorheology of Molecularly Thin Films of n-Hexadecane in Couette Shear Flow by Molecular Dynamics Simulation,” J. of Non-Newtonian Fluid Mechanics, 77(1998) 53-78.  4. *A. Jabbarzadeh, J. D. Atkinson and R. I. Tanner, “Wall Slip in the Molecular Dynamics Simulation of Thin Films of Hexadecane,” J. Chemical Physics, 110 (1999) 2612-2620.  5. *A. Jabbarzadeh, J. D. Atkinson and R. I. Tanner, “The Effect of the Wall Roughness on Slip and Rheological Properties of Hexadecane in Molecular Dynamics Simulation of Couette Shear Flow between Two Sinusoidal Walls” Physical Review E 61 (2000) 690-699.  6. *A. Jabbarzadeh, J. D. Atkinson and R. I. Tanner, The Effect of Branching on Slip and Rheological Properties of Lubricants in Molecular Dynamics Simulation of Couette Shear Flow” Tribology International 35 (2002) 35–46.  7. *A Jabbarzadeh, J. D. Atkinson and R. I. Tanner, “The Effect of Molecular Shape on Rheological Properties in Molecular Dynamics Simulation of Star, H, Comb and Linear Shape Polymer Melts” Macromolecules, 36 (2003) 5020-5031.  8. *A. Jabbarzadeh, P. Harrowell and R. I. Tanner, “The very low friction state of a dodecane film confined between mica surfaces” Physical Review Letters, 94, 126103 (2005).  9. *A. Jabbarzadeh, P. Harrowell and R.I. Tanner,” Crystal bridge formation marks the transition to rigidity in a thin lubrication film” Physical Review Letters, 96, 206102 (2006).  10.  *A. Jabbarzadeh, P. Harrowell, R. I. Tanner, “Crystal bridges, tetratic order, and elusive equilibria: The role of structure in lubrication films”, Journal of Physical Chemistry B 111, 11354-11365 (2007).