Nanorheology of liquid alkanes

We report molecular dynamics simulations of liquid alkanes, squalane and tetracosane, confined between moving walls to which butane chains are tethered, effectively screening the details of the wall. As in an experiment, heat is removed by thermostatting the tethered molecules. Results obtained at high strain rates, typical of practical applications, suggest little or no difference between the bulk rheology and confined flow, and the occurrence of a high degree of slip at the wall–fluid interface at the conditions studied. At relatively low velocities and high densities, the tetracosane conformation becomes fully-extended at certain wall spacings.