Wetting and de-wetting behavior of carbon based electrode materials by imidazolium based ionic liquid: Role of solvophilicity and flexibility

Harender S. Dhattarwal*, Shobha Sharma*, and Hemant K. Kashyap*

* Department of Chemistry, Indian Institute of Technology Delhi

Attributed to the role of ionic liquids in nanoscale-assembly and stabilization of biomolecules such as proteins, understanding the energetics of their interfacial interaction at molecular level is of immense importance. Insights on these details can be gained by studying the surface tension and contact angle along with energetics of the capillary evaporation process. Among these, measuring the contact angle experimentally can be affected by various environmental and laboratory setups such as pressure, moisture and temperature etc. However, we can control these factors more efficiently in computational studies. Thus, here we present the molecular dynamic (MD) simulation studies of biocompatible ionic liquid, 1-butyl-3-methylimidazolium acetate on model hexagonal surfaces. We have studied the effect of varying surface potential from solvophobic to solvophillic range on the contact angle. Effect of surface flexibility by making the nearest neighbor of the sheet harmonically bonded with a spring constant of 600 kJ mol-1A-2 was also investigated. To measure the contact angles, isochoric number density profiles were fitted in equation of circle. Complete dewetting of the surface was observed for both rigid and flexible surfaces in low surface potential region. On increasing the potential well depth the solvophobicity differ in case of rigid and flexible surfaces.

References:

1.      Burt, R.; Birkett, G.; Salanne, M.; Zhao, X. S. The Journal of Physical Chemistry C 2016, 120 (28), 15244-15250.

2.      Peng, H.; Nguyen, A. V.; Birkett, G. R. Molecular Simulation 2012, 38 (12), 945-952.

3.      Herrera, C.; García, G.; Atilhan, M.; Aparicio, S.The Journal of Physical Chemistry C 2015, 119(43), 24529-24537.