Molecular dynamics simulation of dispersion improvement of graphene sheets in nanofluids by steric hindrance resulting from functional groups

Nanofluids are candidate materials for thermal management of heat transfer equipment. Practical applications of thermally enhanced nanofluids contribute to the reduction of weight of systems, leading to improved energy efficiency. Microsize particles sink into the systems because of gravity, therefore rendering the addition meaningless in terms of improving thermal properties. However, nanoparticles can be buoyant, leading to Brownian motion in the fluid, when they do not aggregate with each other. The most important factor in nanofluids is long-term stability of the dispersion in the fluid. Numerous studies have reported the dispersion stability; functional groups attached to nanoparticles play a role in causing steric hindrance and have an affinity for the surrounding fluid, resulting in preserving the dispersion. We investigate the structural effects on dispersion by molecular dynamics simulations of nanofluid containing graphene sheets with functional groups of varying lengths at the surface. ...