Energy polydisperse 2d Lennard-Jones fluid in the presence of flow field

LS Shagolsem, PRAMANA-JOURNAL OF PHYSICS, 96, 182 (2022).

DOI: 10.1007/s12043-022-02435-7

The behaviour of energy polydisperse 2d Lennard-Jones fluid (in thin- film geometry) is studied subjected to linear flow field using molecular dynamics simulations. By considering neutral and selective substrates, we systematically explore the effect of flow field on particle ordering as well as response of the system. It is shown that particle density profile, spatial organisation as well as local particle identity ordering in the film are affected. Furthermore, we observe flow-induced melting associated with a decrease of effective interaction parameter, , which characterises local neighbourhood identity ordering. In terms of macroscopic response, the systems exhibit both shear thinning and shear thickening, and shear thinning exponent decreases with increasing temperature and eventually attains Netwonian fluid-like behaviour at sufficiently high temperature. The onset of shear thinning is governed by the time scale of structural relaxation of the strongly attractive particles. It is found that the qualitative behaviour of the one-component LJ-fluid and energy polydisperse fluid with neutral substrates are similar in many respects, while the one with selective substrate shows differences. In the case of energy polydisperse system, the effect of having different substrate types is significantly manifested in the density profile near the interface, effective interaction parameter and in viscosity.

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