Viscosity to entropy density ratio ($\\eta$/s) in nanoliquid

Abstract

ABSTRACT We present the coefficient of viscosity (), entropy (S) and viscosity to entropy density (s) ratio () for aqueous silver nanoparticle (AgNP) solution at temperatures T = 273–300 K performing experiments and examining the same with discrete dipole approximation (DDA) simulation. The experimental UV-Visible dipole extinction spectra of the nanoliquid, matched with simulations, explore cluster morphologies. The latter is used for the calculation of (cluster volume fraction ~ 4–10%; NP, cluster radii 8–15 nm and 35–55 nm, respectively). In addition, dimer (AgNP-AgNP) formation free energy and S are explored at those T’s. We determine ratio exploiting nanoparticle behaviour. The value of is found lower than that of water and similar to strongly correlated liquid He4, owing to higher S for NP agglomeration. Our results of , S and are also corroborated from hard sphere model calculation. This, to the best of our knowledge, is the first attempt to determine in NP.