A slip-spring framework to study relaxation dynamics of entangled wormlike micelles with kinetic Monte Carlo algorithm

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:600

Article

Pahari, Silabrata^1,2  Bhadriraju, Bhavana^1,2  Akbulut, Mustafa¹  Kwon, Joseph Sang-Il^1,2 

[1] Texas A&M Univ, Artie McFerrin Dept Chem Engn, College Stn, TX 77845 USA

[2] Texas A&M Univ, Texas A&M Energy Inst, College Stn, TX 77845 USA

关键词: Wormlike micelles;    Slip-spring framework;    Kinetic Monte Carlo;    Relaxation dynamics;    Linear rheology;   

DOI  :  10.1016/j.jcis.2021.05.032

来源: Elsevier

【 摘 要 】

Hypothesis: Wormlike micelles (WLMs) formed due to the self-assembly of amphiphiles in aqueous solution have similar viscoelastic properties as polymers. Owing to this similarity, in this work, it is postulated that kinetic Monte Carlo (kMC) sampling of slip-springs dynamics, which is able to model the rheology of polymers, can also be extended to capture the relaxation dynamics of WLMs. Theory: The proposed modeling framework considers the following relaxation mechanisms: reptation, union-scission, and constraint release. Specifically, each of these relaxation mechanisms is simulated as separate kMC events that capture the relaxation dynamics while considering the living nature of WLMs within the slip-spring framework. As a case study, the model is implemented to a system of sodium oleate and sodium chloride to predict the linear rheology and the characteristic relaxation times associated with the individual relaxation mechanisms at different pH and salt concentrations. Findings: Linear rheology predictions were found to be in good agreement with experimental data. Furthermore, the calculated relaxation times highlighted that reptation contributed to a continuous increase in viscosity while union-scission contributed to the decrease in viscosity of WLM solutions at a higher salinity and pH. This manifests the proposed model's capability to provide insights into the key processes governing WLM's rheology. (c) 2021 Elsevier Inc. All rights reserved.

【 授权许可】

Free