Paper Number
SC41
Session
Suspensions & Colloids
Title
Linear viscoelasticity of colloidal suspensions from probe rheology simulations: Application to nanoscopic systems
Presentation Date and Time
October 18, 2018 (Thursday) 9:05
Track / Room
Track 1 / Galleria I
Authors
- Sundaravadivelu Devarajan, Dinesh (Texas Tech University, Department of Chemical Engineering)
- Khare, Rajesh (Texas Tech University, Department of Chemical Engineering)
Author and Affiliation Lines
Dinesh Sundaravadivelu Devarajan and Rajesh Khare
Department of Chemical Engineering, Texas Tech University, Lubbock, TX
Speaker / Presenter
Sundaravadivelu Devarajan, Dinesh
Text of Abstract
The wide-spread industrial applications of colloidal suspensions have led to a significant interest in understanding their structure, flow, and end-use properties. Rheology of nanocolloidal dispersions is governed by interparticle interactions; molecular simulations provide a tool for investigating these effects. Previously, for polymer melts, we showed that the simulated nanoparticle motion in those systems can be analyzed using the inertial generalized Stokes-Einstein relation (IGSER) to predict the linear viscoelasticity of the medium. In this work, we have applied the same formalism to colloidal systems in both the active and the passive modes. The colloidal volume fraction (φ) range investigated in this study covers the regime from dilute suspensions to concentrated suspensions up to the liquid/solid transition point. Dynamic modulus values obtained by analyzing the nanoparticle motion using IGSER are shown to be in good agreement with those calculated from the non-equilibrium molecular dynamics (NEMD) simulations of the same system. Calculated dynamic viscosity values are also found to be consistent with the literature experimental values. In the oscillatory active nanorheology molecular simulations, colloidal distribution around the probe was studied in the context of the Peclet number (Pe) and the oscillation rate (α). Results will also be presented for different size ratios of probe and colloidal particles.