Viscosity and normal stress forces of Lennard-Jones chains using reverse non-equilibrium molecular dynamics

Reverse non-equilibrium molecular dynamics was applied for the calculation of the viscosity for different chain lengths. Each chain consisted of m tangent spherical sites, where m was 1, 2, 4, 8 or 16, respectively. From these results, shear thinning was observed at high shear rates. The normal stress forces were also estimated via the calculation of the total stress tensor, and they were related to the shear thinning effect depending on the length of the chain. Furthermore, a power law equation was used to fit the rheological curves of each chain, making possible the calculation of the viscoelasticity as a function of the sites involved in the chains.