Polybenzimidazole and phosphoric acid based membrane Presently we are looking at Polybenzimidazole (PBI) and Phosphoric acid (PA) based fuel cell membrane in atomistic length scale. In this case we are trying to understand the mechanism of proton conductance and the participation of PBI in that from ab-initio quantum chemical calculation. Simultaneously we are also working on the classical molecular dynamics simulation of the same system to elucidate the formation of hydrogen bond network among PA and PBI molecules. A snapshot of such a system is depicted in the following figure. For further details, please refer: 1.S. Pahari, C.K. Choudhury, P. R. Pandey, M. More, A. Venkatnathan, S. Roy*, Molecular Dynamics Simulation of Phosphoric Acid Doped Monomer of Polybenzimidazole: A Potential Component of Polymer Electrolyte Membrane of fuel cell, The Journal of Physical Chemistry B 2012 116 (24), 7357-7366 2. M. More, S. Pahari, S. Roy*, A Venkatnathan, Characterization of structure and dynamics of phosphoric acid doped benzimidazole mixtures: A molecular dynamics study 3. S. Pahari, and S. Roy*, Evidence and characterization of binary mixtures of phosphoric acid and benzimidazole, J. Chem. Phys. 139, 154701 (2013) Morphology of block co-polymer based membrane Self-assembly process, morphology of block co-polymers etc are large length (micrometer) and long time (microsecond) scale phenomena. To simulate such properties we apply dissipative particle dynamics (DPD) simulation method. The interaction potentials we use for it is only repulsive and related to solubility between different blocks of the systems. The solubility constants are calculated from all atomistic molecular dynamics simulations. So we connect different methods in different scales via parameter transfer. In this way we have used multiscale molecular modeling method for the simulation of phosphonic acid based fuel cell polymer electrolyte membrane. Phosphonic acid based membranes are block co-polymers where phosphonic acid functionalized blocks are responsible for proton transport in fuel cell. We have calculated the mechanism of proton transport in such system and showed that protons are transferred via hydrogen bond network formed by the phosphonic acid blocks. The morphologies of such block copolymers, which are dependent on the composition and topology of different blocks of the copolymer, are calculated by DPD method. The morphology of grafted block copolymer consists of polystyrene backbone and heptylphosphonic acid side-chain looks like the following figure. |
Research >