A mean-field kinetic model suggests that the relaxation dynamics of wormlike micellar networks is a long and complex process due to the problem of reducing the number of free end-caps (or dangling ends) while also reaching an equilibrium level of branching after an earlier overgrowth. The model is validated against mesoscopic molecular dynamics simulations and is based on kinetic equations accounting for scission and synthesis processes of blobs of surfactants. A long relaxation time scale is reached with both thermal quenches and small perturbations of the system. The scaling of this relaxation time is exponential with the free energy of an end cap and with the branching free energy. We argue that the subtle end-recombination dynamics might yield effects that are difficult to detect in rheology experiments, with possible underestimates of the typical time scales of viscoelastic fluids.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1063/5.0072374 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Interactions Between Cationic Micellar Solution and Aromatic Hydrotropes with Subtle Structural Variations.
Molecules
November 2024
School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, China.
Wormlike micelles (WLMs) with tunable viscoelastic characteristics have emerged as indispensable smart materials with a wide range of applications, which have garnered intense interest over the past few decades. However, quantitatively predicting the effect of various hydrotropes on the rheological behaviors of WLMs remains a challenge. In this article, micelles were formed in a mixture of 3-hexadecyloxy-2-hydroxypropyltrimethylammonium bromide (RHTAB) and aromatic hydrotropes (e.
View Article and Find Full Text PDFWormlike Micellar Glycerol Solutions Formed from a Double-Tailed Surfactant with Two Quaternary Ammonium Head Groups.
Langmuir
September 2024
The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China.
Herein, a quaternary ammonium surfactant with dual heads and tails, ,,,,-pentamethyl--(3-(2-tetradecylhexadecanamido)propyl)propane-1,3-diaminium dibromide, abbreviated as Di-C14-N2, was synthesized. For the first time, clear observation of aggregate structures formed by surfactants in pure glycerol systems was achieved using cryogenic transmission electron microscopy (cryo-TEM). The system's rheological properties were analyzed using both steady-state shear and oscillatory rheological measurements.
View Article and Find Full Text PDFFlow of wormlike micellar solutions over concavities.
Soft Matter
September 2024
Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan.
We present a comprehensive investigation combining numerical simulations with experimental validation, focusing on the creeping flow behavior of a shear-banding, viscoelastic wormlike micellar (WLM) solution over concavities with various depths () and lengths (). The fluid is modeled using the diffusive Giesekus model, with model parameters set to quantitatively describe the shear rheology of a 100 : 60 mM cetylpyridinium chloride:sodium salicylate aqueous WLM solution used for the experimental validation. We observe a transition from "cavity flow" to "expansion-contraction flow" as the length exceeds the sum of depth and channel width .
View Article and Find Full Text PDFCryo-electron tomography study of the evolution of wormlike micelles to saturated networks and perforated vesicles.
J Colloid Interface Sci
October 2024
Physics Department, Moscow State University, 119991 Moscow, Russia.
Hypothesis: The formation of micellar aggregates and the changes in their morphology are crucial for numerous practical applications of surfactants. However, a proper structural characterization of complicated micellar nanostructures remains a challenge. This paper demonstrates the advances of cryo-electron tomography (cryo-ET) in revealing the structural characteristics that accompany the evolution of surfactant aggregates.
View Article and Find Full Text PDFShear layers and plugs in the capillary flow of wormlike micellar gels.
Soft Matter
June 2024
Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Ln, Vancouver, British Columbia V6T1Z4, Canada.
Wormlike micellar solutions formed by long-chained zwitterionic surfactants show gel-like rheology at room temperature and have recently been found to exhibit other complex and interesting rheological features. We study the dynamics of these wormlike micellar gels in a pipe-flow scenario using particle imaging and tracking velocimetry and report the existence of plug flows with strong wall slip and non-parabolic velocity profiles for different surfactant concentrations and imposed flow rates. We rationalize these results as features of a developing transient flow of a viscoelastic solution in space and time.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!