Physical adsorption of polyvinyl pyrrolidone on carbon nanotubes under shear studied with dissipative particle dynamics simulations

Dissipative Particle Dynamics (DPD) simulations were used to investigate the conformation of polyvinyl pyrrolidone (PVP) grafted on carbon nanotubes (CNT) and the physical adsorption of the PVP under shear flow. The behavior of PVP on the surface of CNTs was illustrated after the physical adsorption of PVP on the CNT reached equilibrium in an aqueous medium. It was found that PVP molecules prefer to adsorb on the CNT surface and to occupy an “island” area. To examine the structure of CNT-PVP under shear flow, equilibrium CNT-PVP particles were released into Couette and Poiseuille flows. Depending on the shear rate, the polymer could be in one of three configurations: adsorbed, shear-affected and separated. Additionally, the conformation of the polymer was influenced. Average values of the end-to-end distance and the radius of gyration were found to increase when the shear force increases.