Viscosity to entropy density ratio ($\eta$/s) in nanoliquid. (3rd September 2022)

• Record Type: Journal Article
• Authors: Islam, Md Moinul; De, Alokkumar; Pandit, Deepak; Dey, Balaram; Sakib, Nazmus; Bhattacharya, Srijit
• Is Part Of: Physics and chemistry of liquids. Volume 60:Number 5(2022)
• Page Start: 667
• Page End: 681
• Publication Date: 2022-09-03
• Subjects: Nanoliquid -- viscosity -- entropy -- DDA -- DDSCAT -- η/s ratio; Liquids -- Periodicals; 530.4205
• DOI: 10.1080/00319104.2022.2031195
• Languages: English
• ISSNs: 0031-9104

Abstract

ABSTRACT: We present the coefficient of viscosity ( η ), entropy (S) and viscosity to entropy density (s) ratio ( η / s ) 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 η (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 η / s ratio exploiting nanoparticle behaviour. The value of η / s is found lower than that of water and similar to strongly correlated liquid He 4, owing to higher S for NP agglomeration. Our results of η, S and η / s are also corroborated from hard sphere model calculation. This, to the best of our knowledge, is the first attempt to determine η / s in NP.