Modulus--Pressure Equation for Confined Fluids

Published

October 28, 2016

Author(s)

Daniel W. Siderius, Gennady Y. Gor, Vincent K. Shen, Noam Bernstein

Abstract

Ultrasonic experiments allow one to measure the elastic modulus of bulk solid or fluid samples. Recently such experiments have been carried out on fluid-saturated nanoporous glass to probe the modulus of a confined fluid. In our previous work (J. Chem. Phys., 2015, 143, 194506), using Monte Carlo simulations we showed that the elastic modulus $K$ of a fluid confined in a mesopore is a function of the pore size. Here we focus on modulus-pressure dependence $K(P)$, which is known to be linear for bulk materials, a relation known as the Tait-Murnaghan equation. Using transition-matrix Monte Carlo simulations we calculated the elastic modulus of bulk argon and confined in silica mesopores as a function of Laplace pressure. Our calculations show that while the elastic modulus is strongly affected by confinement and temperature, the slope of the modulus- pressure relation is not. Moreover, the calculated slope is in a good agreement with the reference data for bulk argon and experimental data for confined argon derived from ultrasonic experiments. We propose to use the value of the slope of $K(P)$ as a constraint to the analysis of experimental ultrasonic data, to estimate the elastic moduli of an unknown porous medium.

Citation

Journal of Chemical Physics

Volume

145

Pub Type

Journals

Download Paper

https://doi.org/10.1063/1.4965916

Keywords

bulk modulus, confined fluid, adsorption, molecular simulation, thermodynamics, statistical mechanics

Citation

Siderius, D. , Gor, G. , Shen, V. and Bernstein, N. (2016), Modulus--Pressure Equation for Confined Fluids, Journal of Chemical Physics, [online], https://doi.org/10.1063/1.4965916 (Accessed October 31, 2024)