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Smith A, Runde S, Chew AK, Kelkar AS, Maheshwari U, Van Lehn RC, Zavala VM. Topological Analysis of Molecular Dynamics Simulations using the Euler Characteristic. J Chem Theory Comput 2023; 19:1553-1567. [PMID: 36812112 DOI: 10.1021/acs.jctc.2c00766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Molecular dynamics (MD) simulations are used in diverse scientific and engineering fields such as drug discovery, materials design, separations, biological systems, and reaction engineering. These simulations generate highly complex data sets that capture the 3D spatial positions, dynamics, and interactions of thousands of molecules. Analyzing MD data sets is key for understanding and predicting emergent phenomena and in identifying key drivers and tuning design knobs of such phenomena. In this work, we show that the Euler characteristic (EC) provides an effective topological descriptor that facilitates MD analysis. The EC is a versatile, low-dimensional, and easy-to-interpret descriptor that can be used to reduce, analyze, and quantify complex data objects that are represented as graphs/networks, manifolds/functions, and point clouds. Specifically, we show that the EC is an informative descriptor that can be used for machine learning and data analysis tasks such as classification, visualization, and regression. We demonstrate the benefits of the proposed approach through case studies that aim to understand and predict the hydrophobicity of self-assembled monolayers and the reactivity of complex solvent environments.
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Affiliation(s)
- Alexander Smith
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Spencer Runde
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Alex K Chew
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Atharva S Kelkar
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Utkarsh Maheshwari
- Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Reid C Van Lehn
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Victor M Zavala
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, United States
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2
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Yin T, Liu H, Wen X, Wang W, Wang C, Yan Z, Yang Z. pH-responsive clean fracturing fluid based on pseudo-trimeric surfactants. Colloid Polym Sci 2023. [DOI: 10.1007/s00396-023-05053-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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3
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Koide Y, Goto S. Flow-induced scission of wormlike micelles in nonionic surfactant solutions under shear flow. J Chem Phys 2022; 157:084903. [DOI: 10.1063/5.0096830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We investigate flow-induced scission of wormlike micelles with dissipative particle dynamics simulations of nonionic surfactant solutions under shear flow. To understand flow-induced scission in terms of micellar timescales, we propose a method to evaluate the longest relaxation time of unentangled surfactant micelles from the rotational relaxation time and the average lifetime at equilibrium. The mean squared displacement of surfactant molecules provides evidence that the longest relaxation time estimated by the proposed method serves as the characteristic timescale at equilibrium. We also demonstrate that the longest relaxation time plays an essential role in flow-induced scission. Using conditional statistics based on the aggregation number of micelles, we examine the statistical properties of the lifetime of wormlike micelles. We then conclude that flow-induced scission occurs when the Weissenberg number defined as the product of the longest relaxation time and the shear rate is larger than a threshold value.
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Affiliation(s)
- Yusuke Koide
- Osaka University Graduate School of Engineering Science Department of Mechanical Science and Bioengineering, Japan
| | - Susumu Goto
- Graduate School of Engineering Science, Osaka University, Japan
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4
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Peroukidis SD, Stott IP, Mavrantzas VG. Coarse-Grained Model Incorporating Short- and Long-Range Effective Potentials for the Fast Simulation of Micelle Formation in Solutions of Ionic Surfactants. J Phys Chem B 2022; 126:5555-5569. [PMID: 35838193 DOI: 10.1021/acs.jpcb.2c02751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A coarse-grained model comprising short- and long-range effective potentials, parametrized with the iterative Boltzmann inversion (IBI) method, is presented for capturing micelle formation in aqueous solutions of ionic surfactants using as a model system sodium dodecyl sulfate (SDS). In the coarse-grained (CG) model, each SDS molecule is represented as a sequence of four beads while each water molecule is modeled as a single bead. The proposed CG scheme involves ten potential energy functions: four of them describe bonded interactions and control the distribution functions of intramolecular degrees of freedom (bond lengths, valence angles, and dihedrals) along an SDS molecule while the other six account for intermolecular interactions between pairs of SDS and water beads and control the radial distribution functions. The nonbonded effective potentials between coarse-grained SDS molecules extend up to about 12 nm and capture structural and morphological features of the micellar solution both at short and long distances. The long-range component of these potentials, in particular, captures correlations between surfactant molecules belonging to different micelles and is essential to describe ordering associated with micelle formation. A new strategy is introduced for determining the effective potentials through IBI by using information (target distribution functions) extracted from independent atomistic simulations of a micellar reference system (a salt-free SDS solution at total surfactant concentration cT equal to 103 mM, temperature T equal to 300 K, and pressure P equal to 1 atm) obtained through a multiscale approach described in an earlier study. It employs several optimization steps for bonded and nonbonded interactions and a gradual parametrization of the short- and long-range components of the latter, followed by reparametrization of the bonded ones. The proposed CG model can reproduce remarkably accurately the microstructure and morphology of the reference system within only a few hours of computational time. It is therefore very promising for future studies of structural and morphological behavior of various liquid surfactant formulations.
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Affiliation(s)
- Stavros D Peroukidis
- Department of Chemical Engineering, University of Patras and FORTH-ICE/HT, GR 26504, Patras, Greece
| | - Ian P Stott
- Unilever Research and Development Port Sunlight, Bebington CH63 3JW, United Kingdom
| | - Vlasis G Mavrantzas
- Department of Chemical Engineering, University of Patras and FORTH-ICE/HT, GR 26504, Patras, Greece.,Particle Technology Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, CH-8092 Zürich, Switzerland
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5
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Mandal T. Scission energy and topology of micelles controlled by the molecular structure of additives. SOFT MATTER 2022; 18:1678-1687. [PMID: 35137769 DOI: 10.1039/d2sm00040g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We employ coarse-grained (CG) molecular dynamics simulations (MD) to investigate the effects of the molecular structure of additives on the scission energy and morphology of charged micelles. Considering sodium dodecyl sulfate (SDS) as a representative charged surfactant and taking trimethylphenylammonium chloride (TMPAC) and octyltrimethylammonium bromide (OTAB) as oppositely charged additives, we show that the scission energy and topology of micelles vary significantly depending on the molecular structure of the hydrophobic part of the additives. The cyclic aromatic tail of the TMPAC disrupts the core structure of the SDS micelle and hence decreases the micelle scission energy, whereas the linear alkyl tail of the OTAB packs very well with the micelle core and increases the scission energy. Although both the additives have similar head structures, they lead to very different micelle morphologies because of the difference in the shape of their tail structures; ring-like or toroidal shaped micelles are formed in SDS/TMPAC solution whereas bicelle-like structures are formed in SDS/OTAB solution when the additive to surfactant ratio is higher than a certain value.
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Affiliation(s)
- Taraknath Mandal
- Department of Physics, Indian Institute of Technology - Kanpur, Kanpur 208016, India.
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6
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Baiesi M, Iubini S, Orlandini E. The rise and fall of branching: A slowing down mechanism in relaxing wormlike micellar networks. J Chem Phys 2021; 155:214905. [PMID: 34879666 DOI: 10.1063/5.0072374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
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.
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Affiliation(s)
- Marco Baiesi
- Dipartimento di Fisica e Astronomia, Università di Padova, via Marzolo 8, I-35131 Padova, Italy
| | - Stefano Iubini
- Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Enzo Orlandini
- Dipartimento di Fisica e Astronomia, Università di Padova, via Marzolo 8, I-35131 Padova, Italy
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7
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Wen B, Bai B, Larson RG. Surfactant desorption and scission free energies for cylindrical and spherical micelles from umbrella-sampling molecular dynamics simulations. J Colloid Interface Sci 2021; 599:773-784. [PMID: 33989930 DOI: 10.1016/j.jcis.2021.04.138] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 11/28/2022]
Abstract
HYPOTHESIS The free energies associated with adsorption/desorption of individual surfactants from micelles and the fusion/scission of long micelles can be used to estimate the rate constants for micellar kinetics as functions of surfactant and salt concentration. EXPERIMENTS We compute the escape free energies △Gesc of surfactant from micelles and the scission free energies △Gsciss of long micelles from coarse-grained molecular dynamics simulations coupled with umbrella sampling, for micelles of both sodium dodecylsulfate (SDS) in sodium chloride (NaCl) and cetyltrimethylammonium chloride (CTAC) in sodium salicylate (NaSal). FINDINGS For spherical micelles, △Gesc values have maxima at certain aggregation numbers, and at salt-to-surfactant molar concentration ratios R near unity, consistent with experiments. For cylindrical micelles, SDS/NaCl shows a minimum, and CTAC/NaSal a maximum in △Gesc, both at R ~ 0.7, while △Gsciss of CTAC micelles also peaks at around R ~ 0.7 and that of SDS micelles increases monotonically with R. We explain the non-monotonic dependence of escape and scission free energies on R by a combination of electrostatic screening and the decrease of micelle radius with increasing R. Transitions from predominantly spherical to cylindrical micelles, and between adsorption/desorption and fusion/scission kinetics with changing salt concentration can be inferred from the free energies for CTAC/NaSal.
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Affiliation(s)
- Boyao Wen
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, United States; State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Bofeng Bai
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Ronald G Larson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, United States.
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8
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Wang K, Li Z, Huang Y, YaotianTao, Liang X, Chu X, He N, Gui S, Li Z. Additives-directed lyotropic liquid crystals architecture: Simulations and experiments. Int J Pharm 2021; 600:120353. [PMID: 33549811 DOI: 10.1016/j.ijpharm.2021.120353] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 01/17/2021] [Accepted: 01/29/2021] [Indexed: 10/22/2022]
Abstract
In this study, alkanes and sucrose esters are employed to investigate the influence of additives on lyotropic liquid crystal architecture. After molecular dynamic simulations and experiment characterization, we showed how the additives control the structure of LLCs. By controlling the polarity of additives, the phase behavior of LLCs can be engineered to form the required structure. Dissipative particle dynamics (DPD) is introduced for simulating the self-assembly of phytantriol (PT), providing intuitionistic images and structure information, which shows that additives with low-polarity complicate the internal structure of liquid crystal systems. Then the ternary phase diagrams of additives, PT, and water are constructed to systematically study the effects of additives on the phase behavior of LLCs. Consistent with DPD simulation results, there is a certain regularity in the effects of additives on the structure of liquid crystals. The difference in the structure of LLCs is due to the variability in the critical packing parameter (CPP) obtained by changing the polarity of additives. Our findings demonstrate that additives polarity is a key factor in LLCs structure, and may pave a promising avenue for novel LLCs development and translation, determining the self-assembly process and the resulting phase of LLCs.
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Affiliation(s)
- Kang Wang
- Department of Pharmaceutics, College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China
| | - Zhi Li
- Department of Pharmaceutics, College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China
| | - Yiming Huang
- Department of Pharmaceutics, College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China
| | - YaotianTao
- Institute of Pharmaceutics, Anhui Academy of Chinese Medicine, Hefei, China; Engineering Technology Research Center of Modernized Pharmaceutics Anhui Education Department (AUCM), China; Anhui Province Key Laboratory of Pharmaceutical Technology and Application (Anhui University of Chinese Medicine), Hefei, China
| | - Xiao Liang
- Department of Pharmaceutics, College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China
| | - Xiaoqin Chu
- Department of Pharmaceutics, College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China; Institute of Pharmaceutics, Anhui Academy of Chinese Medicine, Hefei, China; Engineering Technology Research Center of Modernized Pharmaceutics Anhui Education Department (AUCM), China; Anhui Province Key Laboratory of Pharmaceutical Technology and Application (Anhui University of Chinese Medicine), Hefei, China
| | - Ning He
- Department of Pharmaceutics, College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China; Institute of Pharmaceutics, Anhui Academy of Chinese Medicine, Hefei, China; Engineering Technology Research Center of Modernized Pharmaceutics Anhui Education Department (AUCM), China; Anhui Province Key Laboratory of Pharmaceutical Technology and Application (Anhui University of Chinese Medicine), Hefei, China
| | - Shuangying Gui
- Department of Pharmaceutics, College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China; Institute of Pharmaceutics, Anhui Academy of Chinese Medicine, Hefei, China; Engineering Technology Research Center of Modernized Pharmaceutics Anhui Education Department (AUCM), China; Anhui Province Key Laboratory of Pharmaceutical Technology and Application (Anhui University of Chinese Medicine), Hefei, China.
| | - Zhenbao Li
- Department of Pharmaceutics, College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China; Institute of Pharmaceutics, Anhui Academy of Chinese Medicine, Hefei, China; Engineering Technology Research Center of Modernized Pharmaceutics Anhui Education Department (AUCM), China; Anhui Province Key Laboratory of Pharmaceutical Technology and Application (Anhui University of Chinese Medicine), Hefei, China
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9
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Endter LJ, Risselada HJ. Where are those lipid nano rings? J Colloid Interface Sci 2020; 587:789-796. [PMID: 33246654 DOI: 10.1016/j.jcis.2020.11.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/06/2020] [Accepted: 11/07/2020] [Indexed: 12/28/2022]
Abstract
Highly curved toroidal micelles with diameters as small as 100 nm have been successfully constructed by self-assembly of amphiphilic block copolymers. These structures may have potential applications in gene or drug delivery. Experimental observations suggest that toroidal micelles likely originate from spherical or disc-like micelles which are tricked into forming toroidal micelles upon external stimuli ('smart' materials). Since self-assembly of polymeric and lipid surfactants is guided by the same physical principles, we hypothesize that 'smart' lipid surfactants can be equivalently tricked into forming highly curved toroidal micelles that are tenfold smaller (≃10 nm diameter). Paradoxically, these 'nano rings' have never been observed. Using coarse-grained molecular dynamics (MD) simulations in conjunction with a state-of-the-art free energy calculation method (a string method), we illustrate how a thermo-responsive lipid surfactant is able to form toroidal micelles. These micelles originate from disc-like micelles that are spontaneously perforated upon heat shocking, thereby supporting a longstanding hypothesis on the possible origin of polymeric toroidal micelle phases observed in experiments. We illustrate that kinetically stable 'nano rings' are substantially shorter lived than their tenfold larger polymeric analogs. The estimated life-time (milliseconds) is in fact similar to the characteristic breaking time of the corresponding worm-like micelle. Finally, we resolve the characteristic finger print which 'nano rings' leave in time-resolved X-ray spectra and illustrate how the uptake of small DNA fragments may enhance their stability. Despite a shared kinetics of self-assembly, length scale dependent differences in the life-time of surfactant phases can occur when phases are kinetically rather than thermodynamically stable. This results in the apparent absence or presence of toroidal micelle phases on different length scales. Our theoretical work precisely illustrates that the universality of surfactants nevertheless remains conserved even at different length scales.
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Affiliation(s)
- Laura Josefine Endter
- Georg-August University Göttingen, Institute for Theoretical Physics, 37077 Göttingen, Germany
| | - Herre Jelger Risselada
- Georg-August University Göttingen, Institute for Theoretical Physics, 37077 Göttingen, Germany; Leiden University, Leiden Institute of Chemistry (LIC), 2311 Leiden, Netherlands.
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10
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Zhou J, Ranjith PG. Self-assembly and viscosity changes of binary surfactant solutions: A molecular dynamics study. J Colloid Interface Sci 2020; 585:250-257. [PMID: 33285463 DOI: 10.1016/j.jcis.2020.11.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 11/15/2022]
Abstract
HYPOTHESIS Structure and self-assembly of surfactants in the solution shows a fundamental influence on its viscosity. Through molecular simulations using Martini force field, synergistic effects in aggregation as well as the viscosity changes of a binary ionic surfactant system can be modelled. Simulations: Coarse-grained molecular dynamics simulations are performed to model the SDS/CAPB binary surfactant solution, and both equilibrium and non-equilibrium methods are used to calculate the viscosity of the equilibrated micellar systems. FINDINGS Our simulation results indicate that the new version of the Martini force field can provide more reasonable self-assembly of surfactant, both single and binary system. Synergistic effects in micelle formation for SDS/CAPB have been successfully reproduced, that is, the formation of cylindrical micelles or even wormlike micelles at a lower concentration when compared with the pure system. Meanwhile, both equilibrium and non-equilibrium methods provide quantitatively comparable viscosity for each system. For pure micellar system, the viscosity linearly increases with the total concentration. Nevertheless, our simulation fails to capture the viscosity enhancement of the solution in corresponding with the formation of rodlike or wormlike micelles, and a full parameter optimization of force field is still necessary.
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Affiliation(s)
- Jun Zhou
- Department of Civil Engineering, Monash University, Building 60, Melbourne, Victoria 3800, Australia
| | - P G Ranjith
- Department of Civil Engineering, Monash University, Building 60, Melbourne, Victoria 3800, Australia.
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11
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Iubini S, Baiesi M, Orlandini E. Aging of living polymer networks: a model with patchy particles. SOFT MATTER 2020; 16:9543-9552. [PMID: 32968747 DOI: 10.1039/d0sm01391a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Microrheology experiments show that viscoelastic media composed by wormlike micellar networks display complex relaxations lasting seconds even at the scale of micrometers. By mapping a model of patchy colloids with suitable mesoscopic elementary motifs to a system of worm-like micelles, we are able to simulate its relaxation dynamics, upon a thermal quench, spanning many decades, from microseconds up to tens of seconds. After mapping the model to real units and to experimental scission energies, we show that the relaxation process develops through a sequence of non-local and energetically challenging arrangements. These adjustments remove undesired structures formed as a temporary energetic solution for stabilizing the thermodynamically unstable free caps of the network. We claim that the observed scale-free nature of this stagnant process may complicate the correct quantification of experimentally relevant time scales as the Weissenberg number.
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Affiliation(s)
- Stefano Iubini
- Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy. and Dipartimento di Fisica e Astronomia, Università di Padova, Via Marzolo 8, I-35131 Padova, Italy
| | - Marco Baiesi
- Dipartimento di Fisica e Astronomia, Università di Padova, Via Marzolo 8, I-35131 Padova, Italy and INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova, Italy
| | - Enzo Orlandini
- Dipartimento di Fisica e Astronomia, Università di Padova, Via Marzolo 8, I-35131 Padova, Italy and INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova, Italy
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12
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Conchuir BO, Gardner K, Jordan KE, Bray DJ, Anderson RL, Johnston MA, Swope WC, Harrison A, Sheehy DR, Peters TJ. Efficient Algorithm for the Topological Characterization of Worm-like and Branched Micelle Structures from Simulations. J Chem Theory Comput 2020; 16:4588-4598. [DOI: 10.1021/acs.jctc.0c00311] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | - Kirk Gardner
- Department of Computer Science & Engineering, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Kirk E. Jordan
- IBM T. J. Watson Research, Cambridge, Massachusetts 02142, United States
| | - David J. Bray
- The Hartree Centre, STFC Daresbury Laboratory, Warrington WA4 4AD, U.K
| | | | | | - William C. Swope
- IBM Almaden Research Center, San Jose, California 95120, United States
| | - Alex Harrison
- IBM Research Europe, The Hartree Centre, Daresbury WA4 4AD, U.K
| | - Donald R. Sheehy
- Department of Computer Science, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Thomas J. Peters
- Department of Computer Science & Engineering, University of Connecticut, Storrs, Connecticut 06269, United States
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13
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Liu F, Liu D, Zhou W, Wang S, Chen F, Wei J. Weakening or losing of surfactant drag reduction ability: A coarse-grained molecular dynamics study. Chem Eng Sci 2020. [DOI: 10.1016/j.ces.2020.115610] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Zhou J, Ranjith P, Wanniarachchi W. Different strategies of foam stabilization in the use of foam as a fracturing fluid. Adv Colloid Interface Sci 2020; 276:102104. [PMID: 31978640 DOI: 10.1016/j.cis.2020.102104] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 01/01/2020] [Accepted: 01/06/2020] [Indexed: 10/25/2022]
Abstract
An attractive alternative to mitigate the adverse effects of conventional water-based fluids on the efficiency of hydraulic fracturing is to inject foam-based fracking fluids into reservoirs. The efficiency of foaming fluids in subsurface applications largely depends on the stability and transportation of foam bubbles in harsh environments with high temperature, pressure and salinity, all of which inevitably lead to poor foam properties and thus limit fracturing efficiency. The aim of this paper is to elaborate popular strategies of foam stabilization under reservoir conditions. Specifically, this review first discusses three major mechanisms governing foam decay and summarizes recent progress in research on these phenomena. Since surfactants, polymers, nanoparticles and their composites are popular options for foam stabilization, their stabilizing effects, especially the synergies in composites, are also reviewed. In addition to reporting experimental results, the paper also reports recent advances in interfacial properties via molecular dynamical simulation, which provide new insights into gas/liquid interfacial properties under the influence of surfactants at molecular scale. The results of both experiments and simulations indicate that foam additives play an essential role in foam stability and the synergic effects of surfactants and nanoparticles exhibit more favorable performance.
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15
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Liu D, Li Y, Liu F, Zhou W, Sun A, Liu X, Chen F, Xu BB, Wei J. Interfacial Interaction Enhanced Rheological Behavior in PAM/CTAC/Salt Aqueous Solution-A Coarse-Grained Molecular Dynamics Study. Polymers (Basel) 2020; 12:polym12020265. [PMID: 31991789 PMCID: PMC7077399 DOI: 10.3390/polym12020265] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 01/19/2020] [Accepted: 01/21/2020] [Indexed: 11/16/2022] Open
Abstract
Interfacial interactions within a multi-phase polymer solution play critical roles in processing control and mass transportation in chemical engineering. However, the understandings of these roles remain unexplored due to the complexity of the system. In this study, we used an efficient analytical method-a nonequilibrium molecular dynamics (NEMD) simulation-to unveil the molecular interactions and rheology of a multiphase solution containing cetyltrimethyl ammonium chloride (CTAC), polyacrylamide (PAM), and sodium salicylate (NaSal). The associated macroscopic rheological characteristics and shear viscosity of the polymer/surfactant solution were investigated, where the computational results agreed well with the experimental data. The relation between the characteristic time and shear rate was consistent with the power law. By simulating the shear viscosity of the polymer/surfactant solution, we found that the phase transition of micelles within the mixture led to a non-monotonic increase in the viscosity of the mixed solution with the increase in concentration of CTAC or PAM. We expect this optimized molecular dynamic approach to advance the current understanding on chemical-physical interactions within polymer/surfactant mixtures at the molecular level and enable emerging engineering solutions.
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Affiliation(s)
- Dongjie Liu
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China; (D.L.); (W.Z.)
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China;
| | - Yong Li
- Drilling and Production Engineering Research Institute, Chuanqing Drilling and Exploration Engineering Company Ltd., CNPC, Xi’an 710018, China;
| | - Fei Liu
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China;
| | - Wenjing Zhou
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China; (D.L.); (W.Z.)
| | - Ansu Sun
- Mechanical and Construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK; (A.S.); (X.L.)
| | - Xiaoteng Liu
- Mechanical and Construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK; (A.S.); (X.L.)
| | - Fei Chen
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China; (D.L.); (W.Z.)
- Correspondence: (F.C.); (B.B.X.); (J.W.); Tel.: +86-029-82664375 (J.W.)
| | - Ben Bin Xu
- Mechanical and Construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK; (A.S.); (X.L.)
- Correspondence: (F.C.); (B.B.X.); (J.W.); Tel.: +86-029-82664375 (J.W.)
| | - Jinjia Wei
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China; (D.L.); (W.Z.)
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China;
- Correspondence: (F.C.); (B.B.X.); (J.W.); Tel.: +86-029-82664375 (J.W.)
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16
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Constructing the phase diagram of sodium laurylethoxysulfate using dissipative particle dynamics. J Colloid Interface Sci 2019; 557:34-44. [DOI: 10.1016/j.jcis.2019.08.091] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/23/2019] [Accepted: 08/24/2019] [Indexed: 01/08/2023]
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17
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Zhou W, Liu F, Liu D, Chen F, Wei J. Energy analysis of a surfactant micelle’s deformation by coarse-grained molecular dynamics simulations. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.03.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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18
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Sagisaka M, Saito T, Yoshizawa A, Rogers SE, Guittard F, Hill C, Eastoe J, Blesic M. Water-in-CO 2 Microemulsions Stabilized by Fluorinated Cation-Anion Surfactant Pairs. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:3445-3454. [PMID: 30739456 DOI: 10.1021/acs.langmuir.8b03942] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
High-water-content water-in-supercritical CO2 (W/CO2) microemulsions are considered to be green, universal solvents, having both polar and nonpolar domains. Unfortunately, these systems generally require environmentally unacceptable stabilizers like long and/or multifluorocarbon-tail surfactants. Here, a series of catanionic surfactants having more environmentally friendly fluorinated C4-C6 tails have been studied in terms of interfacial properties, aggregation behavior, and solubilizing power in water and/or CO2. Surface tensions and critical micelle concentrations of these catanionic surfactants are, respectively, lowered by ∼9 mN/m and 100 times than those of the constituent single fluorocarbon-tail surfactants. Disklike micelles in water were observed above the respective critical micelle concentrations, implying the catanionic surfactants have a high critical packing parameter, which should be suitable for the formation of reverse micelles. Based on visual observation of phase behavior and Fourier transform infrared spectroscopic and small-angle neutron scattering studies, one of the three catanionic surfactants tested was found to form transparent single-phase W/CO2 microemulsions with a water-to-surfactant molar ratio of up to ∼50. This is the first successful demonstration of the formation of W/CO2 microemulsions by synergistic ion-pairing of anionic and cationic single-tail surfactants. This indicates that catanionic surfactants offer a promising approach to generate high-water-content W/CO2 microemulsions.
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Affiliation(s)
- Masanobu Sagisaka
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology , Hirosaki University , 3 Bunkyo-cho , Hirosaki , Aomori 036-8561 , Japan
| | - Tatsuya Saito
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology , Hirosaki University , 3 Bunkyo-cho , Hirosaki , Aomori 036-8561 , Japan
| | - Atsushi Yoshizawa
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology , Hirosaki University , 3 Bunkyo-cho , Hirosaki , Aomori 036-8561 , Japan
| | - Sarah E Rogers
- ISIS-CCLRC, Rutherford Appleton Laboratory , Chilton OX11 0QX , Oxon , U.K
| | - Frédéric Guittard
- Univ. Cote d'Azur, NICE-Lab , 61-63 av. S. Viel , 06200 Nice , France
| | - Christopher Hill
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , U.K
| | - Julian Eastoe
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , U.K
| | - Marijana Blesic
- School of Chemistry and Chemical Engineering , Queen's University Belfast , University Road , Belfast BT7 1NN , U.K
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19
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Mandal T, Larson RG. Stretch and Breakage of Wormlike Micelles under Uniaxial Strain: A Simulation Study and Comparison with Experimental Results. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:12600-12608. [PMID: 30251869 DOI: 10.1021/acs.langmuir.8b02421] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We use coarse-grained (CG) molecular dynamics simulations to determine the effect of uniaxial strain on the stress, scission stress, and scission energy of solutions of wormlike micelles of cetyltrimethylammonium chloride/sodium salicylate (NaSal). We find that the breaking stress, stretch modulus, and scission energy of the charged micelles are nonmonotonic functions of oppositely charged hydrotrope (NaSal) concentration. While the stretch modulus shows a peak at a value of surfactant-to-hydrotrope concentration ratio ( R) close to unity as expected due to neutralization of head-group charge at R = 1, the breaking stress and scission energy produce a peak at R < 1.0 because of thinning of the micelle diameter with increased R. The breaking stress from the simulations depends on the rate of deformation and roughly agrees with the experimental values of Rothstein ( J. Rheol. 2003 , 47 , 1227 ) after extrapolation to the much lower experimental rates. The method and results can be used to predict the effects of flow and mechanical stress on rates of micellar breakage, which is important in the rheology of wormlike micellar solutions.
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Affiliation(s)
- Taraknath Mandal
- Department of Chemical Engineering , University of Michigan , 10-A150 NCRC, 2800 Plymouth Ave. , Ann Arbor , Michigan 48109 , United States
| | - Ronald G Larson
- Department of Chemical Engineering , University of Michigan , 10-A150 NCRC, 2800 Plymouth Ave. , Ann Arbor , Michigan 48109 , United States
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20
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Custer GS, Xu H, Matysiak S, Das P. How Hydrophobic Hydration Destabilizes Surfactant Micelles at Low Temperature: A Coarse-Grained Simulation Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:12590-12599. [PMID: 30247911 DOI: 10.1021/acs.langmuir.8b01994] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Micelles are self-assembled aggregates of amphiphilic surfactant molecules that are important in a variety of applications, including drug delivery, detergency, and catalysis. It is known that the micellization process is driven by the same physiochemical forces that drive protein folding, aggregation, and biological membrane self-assembly. Nevertheless, the molecular details of how micelle stability changes in water at low temperature are not fully clear. We develop and use a coarse-grained model to investigate how the interplay between nonionic surfactants and the surrounding water at the nanoscale affects the stability of micelles at high and low temperatures. Simulations of preformed C12E5 micelles in explicit water at a range of temperatures reveal the existence of two distinct surfactant conformations within the micelle, a bent structure and an extended structure, the latter being more prevalent at low temperature. Favorable interactions of the surfactant with more ordered solvation water stabilizes the extended configuration, allowing nanoscale wetting of the dry, hydrophobic core of the micelle, leading to the micelle breaking. Taken together, our coarse-grained simulations unravel how energetic and structural changes of the surfactant and the surrounding water destabilize micelles at low temperature, which is a direct consequence of the weakened hydrophobicity. Our approach thus provides an effective mean for extracting the molecular-level changes during hydrophobicity-driven destabilization of molecular self-assembly, which is important in a wide range of fields, including biology, polymer science, and nanotechnology.
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Affiliation(s)
| | | | | | - Payel Das
- IBM Thomas J. Watson Research Center , Yorktown Heights, New York 10598 , United States
- Department of Applied Physics and Applied Mathematics , Columbia University , New York 10027 , United States
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21
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Coarse-grained molecular dynamics study on the rheological behaviors of surfactant aqueous solution. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.06.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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22
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Sagisaka M, Ono S, James C, Yoshizawa A, Mohamed A, Guittard F, Enick RM, Rogers SE, Czajka A, Hill C, Eastoe J. Anisotropic reversed micelles with fluorocarbon-hydrocarbon hybrid surfactants in supercritical CO 2. Colloids Surf B Biointerfaces 2018; 168:201-210. [PMID: 29276082 DOI: 10.1016/j.colsurfb.2017.12.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/28/2017] [Accepted: 12/09/2017] [Indexed: 11/19/2022]
Abstract
Previous work (M. Sagisaka, et al. Langmuir 31 (2015) 7479-7487), showed the most effective fluorocarbon (FC) and hydrocarbon (HC) chain lengths in the hybrid surfactants FCm-HCn (sodium 1-oxo-1-[4-(perfluoroalkyl)phenyl]alkane-2-sulfonates, where m = FC length and n = HC length) were m and n = 6 and 4 for water solubilization, whereas m 6 and n 6, or m 6 and n 5, were optimal chain lengths for reversed micelle elongation in supercritical CO2. To clarify why this difference of only a few methylene chain units is so effective at tuning the solubilizing power and reversed micelle morphology, nanostructures of water-in-CO2 (W/CO2) microemulsions were investigated by high-pressure small-angle neutron scattering (SANS) measurements at different water-to-surfactant molar ratios (W0) and surfactant concentrations. By modelling SANS profiles with cylindrical and ellipsoidal form factors, the FC6-HCn/W/CO2 microemulsions were found to increase in size with increasing W0 and surfactant concentration. Ellipsoidal cross-sectional radii of the FC6-HC4/W/CO2 microemulsion droplets increased linearly with W0, and finally reached ∼39 Å and ∼78 Å at W0 = 85 (close to the upper limit of solubilizing power). These systems appear to be the largest W/CO2 microemulsion droplets ever reported. The aqueous domains of FC6-HC6 rod-like reversed micelles increased in size by 3.5 times on increasing surfactant concentration from 35 mM to 50 mM: at 35 mM, FC6-HC5 formed rod-like reversed micelles 5.3 times larger than FC6-HC6. Interestingly, these results suggest that hybrid HC-chains partition into the microemulsion aqueous cores with the sulfonate headgroups, or at the W/CO2 interfaces, and so play important roles for tuning the W/CO2 interfacial curvature. The super-efficient W/CO2-type solubilizer FC6-HC4, and the rod-like reversed micelle forming surfactant FC6-HC5, represent the most successful cases of low fluorine content additives. These surfactants facilitate VOC-free, effective and energy-saving CO2 solvent systems for applications such as extraction, dyeing, dry cleaning, metal-plating, enhanced oil recovery and organic/inorganic or nanomaterial synthesis.
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Affiliation(s)
- Masanobu Sagisaka
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan.
| | - Shinji Ono
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan
| | - Craig James
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan
| | - Atsushi Yoshizawa
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan
| | - Azmi Mohamed
- Department of Chemistry, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, 35900 Tanjong Malim, Perak, Malaysia; Nanotechnology Research Centre, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, 35900 Tanjong Malim, Perak, Malaysia
| | | | - Robert M Enick
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, 940 Benedum Hall, 3700 O'Hara Street, Pittsburgh, PA 15261, United States
| | - Sarah E Rogers
- ISIS-CCLRC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, UK
| | - Adam Czajka
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - Christopher Hill
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - Julian Eastoe
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
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23
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Mandal T, Koenig PH, Larson RG. Nonmonotonic Scission and Branching Free Energies as Functions of Hydrotrope Concentration for Charged Micelles. PHYSICAL REVIEW LETTERS 2018; 121:038001. [PMID: 30085808 DOI: 10.1103/physrevlett.121.038001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 04/30/2018] [Indexed: 06/08/2023]
Abstract
Using coarse-grained molecular dynamics simulations and an umbrella sampling method that uses local surfactant density as a reaction coordinate, we directly calculate, for the first time, both the scission and branching free energies of a model charged micelle [cationic cetyltrimethylammonium chloride (CTAC)] in the presence of inorganic and organic salts (hydrotropes). We find that while inorganic salt only weakly affects the micelle scission energy, organic hydrotropes produce a strong, nonmonotonic dependence of both scission energy and branching on salt concentration. The nonmonotonicity in scission energy is traced to a competition between electrostatic screening of the repulsions among the surfactant head groups and thinning of the micellar core, which result from attachment of the hydrotropes to the micelle surface. We are able to correlate the nonmonotonicity in the scission energy of CTAC micelles with the peak observed experimentally in viscosity versus hydrotrope concentration and the location of this peak in CTAC solutions.
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Affiliation(s)
- Taraknath Mandal
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Peter H Koenig
- Computational Chemistry, Modeling and Simulation, The Procter & Gamble Company, 8611 Beckett Road, West Chester, Ohio 45069, USA
| | - Ronald G Larson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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24
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Zhang J, Zhang Y, Li J, Wang P, Sun X, Yan Y. Effect of organic salt on the self-assembly of ammonium gemini surfactant: An experiment and simulation study. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2018.01.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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25
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Calabrese MA, Wagner NJ. Detecting Branching in Wormlike Micelles via Dynamic Scattering Methods. ACS Macro Lett 2018; 7:614-618. [PMID: 35632965 DOI: 10.1021/acsmacrolett.8b00188] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Topological differences in a model series of wormlike micelles (WLMs) with varying degrees of branching are investigated via neutron spin echo (NSE) and dynamic light scattering (DLS). Branching was previously verified via microscopy, scattering methods, and rheology. NSE measurements reveal that on the shortest length scales, where WLMs are topologically similar, the dynamic behavior is independent of branching level. However, branching leads to deviations from wormlike chain behavior on length scales relevant to branching. These differences continue into the DLS regime, where two relaxation modes are observed. While measuring micellar branching is challenging, our measurements of segmental dynamics provide a direct dynamic measurement of WLM branching and demonstrate promise for future identification of topological changes in self-assembled materials.
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Affiliation(s)
- Michelle A. Calabrese
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Norman J. Wagner
- Center for Neutron Science, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
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26
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Liu F, Liu D, Zhou W, Chen F, Wei J. Coarse-Grained Molecular Dynamics Simulations of the Breakage and Recombination Behaviors of Surfactant Micelles. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.8b01490] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fei Liu
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Dongjie Liu
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Wenjing Zhou
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China
| | - Fei Chen
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China
| | - Jinjia Wei
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China
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27
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Danov KD, Kralchevsky PA, Stoyanov SD, Cook JL, Stott IP, Pelan EG. Growth of wormlike micelles in nonionic surfactant solutions: Quantitative theory vs. experiment. Adv Colloid Interface Sci 2018; 256:1-22. [PMID: 29804690 DOI: 10.1016/j.cis.2018.05.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 11/25/2022]
Abstract
Despite the considerable advances of molecular-thermodynamic theory of micelle growth, agreement between theory and experiment has been achieved only in isolated cases. A general theory that can provide self-consistent quantitative description of the growth of wormlike micelles in mixed surfactant solutions, including the experimentally observed high peaks in viscosity and aggregation number, is still missing. As a step toward the creation of such theory, here we consider the simplest system - nonionic wormlike surfactant micelles from polyoxyethylene alkyl ethers, CiEj. Our goal is to construct a molecular-thermodynamic model that is in agreement with the available experimental data. For this goal, we systematized data for the micelle mean mass aggregation number, from which the micelle growth parameter was determined at various temperatures. None of the available models can give a quantitative description of these data. We constructed a new model, which is based on theoretical expressions for the interfacial-tension, headgroup-steric and chain-conformation components of micelle free energy, along with appropriate expressions for the parameters of the model, including their temperature and curvature dependencies. Special attention was paid to the surfactant chain-conformation free energy, for which a new more general formula was derived. As a result, relatively simple theoretical expressions are obtained. All parameters that enter these expressions are known, which facilitates the theoretical modeling of micelle growth for various nonionic surfactants in excellent agreement with the experiment. The constructed model can serve as a basis that can be further upgraded to obtain quantitative description of micelle growth in more complicated systems, including binary and ternary mixtures of nonionic, ionic and zwitterionic surfactants, which determines the viscosity and stability of various formulations in personal-care and house-hold detergency.
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28
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Mandal T, Larson RG. Prediction of striped cylindrical micelles (SCMs) formed by dodecyl-β-d-maltoside (DDM) surfactants. SOFT MATTER 2018; 14:2694-2700. [PMID: 29565444 DOI: 10.1039/c8sm00274f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Using fully atomistic and coarse-grained (CG) molecular dynamics (MD) simulations, we report, for the first time, the self-assembly of initially randomly dispersed dodecyl-β-d-maltoside (DDM) surfactants into a striped cylindrical micelle (SCM) with lamellae of surfactant heads and tails alternating along the cylindrical axis, with both heads and tails in contact with the water. By changing the interaction strength of the head group with water relative to itself, we find that such micelles are most likely for head groups with marginal solubility in the water solvent. Unlike the surfactants in a regular cylindrical micelle, whose tails are in the fluid micelle interior, the diffusion of DDM surfactants along the micelle body is blocked by the lamellar patterning. As a consequence, branches cannot slide along the micelle body and surfactant molecules cannot exchange between the micelle body and the branch, which should have a significant impact on the rheological properties of these micelles.
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Affiliation(s)
- Taraknath Mandal
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI-48109, USA.
| | - Ronald G Larson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI-48109, USA.
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29
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Wang H, Tang X, Eike DM, Larson RG, Koenig PH. Scission Free Energies for Wormlike Surfactant Micelles: Development of a Simulation Protocol, Application, and Validation for Personal Care Formulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:1564-1573. [PMID: 29244513 DOI: 10.1021/acs.langmuir.7b03552] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present a scheme to calculate wormlike micelle scission free energies from a potential of mean force (PMF) derived from a weighted histogram analysis method (WHAM) applied to coarse grained dissipative particle dynamics (DPD) simulations. In contrast to previous related work, we use a specially chosen external potential based on a reaction coordinate that reversibly drives surfactants out of the nascent scission location. For the application to a model body wash formulation, we predict how addition of NaCl and small molecules such as perfume raw materials (PRMs) affect scission energies. The results show qualitative agreement and correct trends compared to recently determined scission energies for the same system; however, a more rigorous parametrization of the underlying DPD potential is required for quantitative agreement.
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Affiliation(s)
- Huan Wang
- University of Cincinnati Simulation Center , 2728 Vine Street, Cincinnati, Ohio 45220, United States
| | - Xueming Tang
- Department of Chemical Engineering, 2800 Plymouth Road, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - David M Eike
- Computational Chemistry, Modeling and Simulation, The Procter & Gamble Company , 8611 Beckett Road, West Chester, Ohio 45069, United States
| | - Ronald G Larson
- Department of Chemical Engineering, 2800 Plymouth Road, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Peter H Koenig
- Computational Chemistry, Modeling and Simulation, The Procter & Gamble Company , 8611 Beckett Road, West Chester, Ohio 45069, United States
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30
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Sambasivam A, Dhakal S, Sureshkumar R. Structure and rheology of self-assembled aqueous suspensions of nanoparticles and wormlike micelles. MOLECULAR SIMULATION 2017. [DOI: 10.1080/08927022.2017.1387658] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Abhinanden Sambasivam
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY, USA
| | - Subas Dhakal
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY, USA
| | - Radhakrishna Sureshkumar
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY, USA
- Department of Physics, Syracuse University, Syracuse, NY, USA
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31
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Asgari M. Micro-mechanical, continuum-mechanical, and AFM-based descriptions of elasticity in open cylindrical micellar filaments. SOFT MATTER 2017; 13:7112-7128. [PMID: 28858368 PMCID: PMC5636689 DOI: 10.1039/c7sm00911a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present theoretical and experimental descriptions of the elasticity of cylindrical micellar filaments using micro-mechanical and continuum theories, and atomic force microscopy. Following our micro-mechanical elasticity model for micellar filaments [M. Asgari, Eur. Phys. J. E: Soft Matter Biol. Phys., 2015, 38(9), 1-16], the elastic bending energy of hemispherical end caps is found. The continuum description of the elastic bending energy of a cylindrical micellar filament is also derived using constrained Cosserat rod theory. While the continuum approach provides macroscopic description of the strain energy of the micellar filament, the micro-mechanical approach has a microscopic view of the filament, and provides expressions for kinetic variables based on a selected interaction potential between the molecules comprising the filament. Our model predicts the dependence of the elastic modulus of the micellar filaments on their diameter, which agrees with previous experimental observations. Atomic force microscopy is applied to estimate the elastic modulus of the filaments using force volume analysis. The obtained values of elastic modulus yield the persistence length of micellar filaments on the same order of the previously reported values. Consistent with previous studies, our results indicate that semi-flexible linear micelles have a relatively large local strain energy at their end points, which explains their tendency to fuse to minimize the number of end caps at relatively low total surfactant volume fractions. Also, the elastic modulus of micellar filaments was found to increase when the indentation frequency increases, a finding which agrees with previous rheological observations on the bulk shear modulus of micellar solutions.
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Affiliation(s)
- Meisam Asgari
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, QC H3A 0C3, Canada.
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32
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Wu QY, Tian WD, Ma YQ. Modeling the Self-Assembly of Bolaamphiphiles under Nanoconfinement by Coarse-Grained Molecular Dynamics. J Phys Chem B 2017; 121:8984-8990. [DOI: 10.1021/acs.jpcb.7b04015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Qing-Yan Wu
- National
Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
| | - Wen-de Tian
- Center
for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, China
| | - Yu-qiang Ma
- National
Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
- Center
for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, China
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33
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Wang P, Tan J, Pei S, Wang J, Zhang Y, Sun X, Zhang J. Dual effects of cationic surfactant on the wormlike micelle formation of catanionic surfactants mixtures: An experiment and simulation study. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.05.079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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34
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Dhakal S, Sureshkumar R. Anomalous diffusion and stress relaxation in surfactant micelles. Phys Rev E 2017; 96:012605. [PMID: 29347138 DOI: 10.1103/physreve.96.012605] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Indexed: 06/07/2023]
Abstract
We investigate the mechanisms of anomalous diffusion in cationic surfactant micelles using molecular dynamics simulations in the presence of explicit salt and solvent-mediated interactions. Simulations show that when the counterion density increases, saddle-shaped branched interfaces manifest. In experiments, branched structures exhibit lower viscosity as compared to linear and wormlike micelles. This has long been attributed to stress relaxation arising from the sliding motion of branches along the main chain. Our simulations reveal a mechanism of branch motion resulting from an enhanced counterion condensation at the branched interfaces and provide quantitative evidence of stress relaxation facilitated by branched sliding. Furthermore, depending on the surfactant and salt concentrations, which in turn determine the microstructure, we observe normal, subdiffusive, and superdiffusive motions of surfactants. Specifically, superdiffusive behavior is associated with branch sliding, breakage and recombination of micelle fragments, as well as constraint release in entangled systems.
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Affiliation(s)
- Subas Dhakal
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, USA
| | - Radhakrishna Sureshkumar
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, USA and Department of Physics, Syracuse University, Syracuse, New York 13244, USA
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35
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Wang M, Fang T, Wang P, Yan Y, Zhang J, Liu B, Sun X. Molecular-Scale Design of Hydrocarbon Surfactant Self-Assembly in Supercritical CO 2. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:5291-5297. [PMID: 28485950 DOI: 10.1021/acs.langmuir.7b01176] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Forming wormlike reverse micelles (RMs) by hydrocarbon surfactant self-assembly is an economic and environmental strategy to improve the physicochemical properties of supercritical carbon dioxide (scCO2), but it remains challenging. Introducing cosurfactant in hydrocarbon surfactant self-assembly system is a potential method to generate wormlike RMs. Here, adopting molecular dynamics simulations, we performed hydrocarbon surfactant (TC14) self-assembly with introducing cosurfactants (C8Benz). It is found that adding the C8Benz molecules will induce the spherical RMs to a short rodlike form. In this case, the microstructure of the short rodlike RMs shows a dumbbell-like form that is composed by three parts including a middle part of C8Benz and two parts of TC14 aggregation at both ends of rodlike RMs, which is regarded as the origin of RMs shape transition. Further, the analysis of free energy for RMs fusion indicates that the high fusion ability of C8Benz aggregation drives the formation of the dumbbell-like RMs. Accordingly, enhancing the affinity of the C8Benz is found to be effective strategy to further fusion of rodlike RMs in end-to-end manner, yielding a wormlike RMs with a beads-on-a-string structure. It is expected that this work will provide a valuable information for design the hydrocarbon wormlike RMs and facilitate the potential application of scCO2.
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Affiliation(s)
- Muhan Wang
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Timing Fang
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Pan Wang
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Youguo Yan
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Jun Zhang
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Bing Liu
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Xiaoli Sun
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
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36
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Study on the transformation from linear to branched wormlike micelles: An insight from molecular dynamics simulation. J Colloid Interface Sci 2017; 494:47-53. [DOI: 10.1016/j.jcis.2017.01.057] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 01/14/2017] [Accepted: 01/17/2017] [Indexed: 11/17/2022]
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37
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Gaudino D, Pasquino R, Kriegs H, Szekely N, Pyckhout-Hintzen W, Lettinga MP, Grizzuti N. Effect of the salt-induced micellar microstructure on the nonlinear shear flow behavior of ionic cetylpyridinium chloride surfactant solutions. Phys Rev E 2017; 95:032603. [PMID: 28415244 DOI: 10.1103/physreve.95.032603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Indexed: 06/07/2023]
Abstract
The shear flow dynamics of linear and branched wormlike micellar systems based on cetylpyridinium chloride and sodium salicylate in brine solution is investigated through rheometric and scattering techniques. In particular, the flow and the structural flow response are explored via velocimetry measurements and rheological and rheometric small-angle neutron scattering (SANS) experiments, respectively. Although all micellar solutions display a similar shear thinning behavior in the nonlinear regime, the experimental results show that shear banding sets in only when the micelle contour length L[over ¯] is sufficiently long, independent of the nature of the micellar connections (either linear or branched micelles). Using rheometric SANS, we observe that the shear banding systems both show very similar orientational ordering as a function of Weissenberg number, while the short branched micelles manifest an unexpected increase of ordering at very low Weissenberg numbers. This suggests the presence of an additional flow-induced relaxation process that is peculiar for branched systems.
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Affiliation(s)
- D Gaudino
- Dipartimento di Ingegneria Chimica, dei Materiali d della Produzione Industriale, Università degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli, Italy
| | - R Pasquino
- Dipartimento di Ingegneria Chimica, dei Materiali d della Produzione Industriale, Università degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli, Italy
| | - H Kriegs
- Institute for Complex Systems, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - N Szekely
- Jülich Centre for Neutron Science Outstation at MLZ, Lichtenbergstrasse 1, 85747 Garching, Germany
| | - W Pyckhout-Hintzen
- Jülich Centre for Neutron Science, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - M P Lettinga
- Institute for Complex Systems, Forschungszentrum Jülich, 52425 Jülich, Germany
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - N Grizzuti
- Dipartimento di Ingegneria Chimica, dei Materiali d della Produzione Industriale, Università degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli, Italy
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38
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Gaudino D, Pasquino R, Stellbrink J, Szekely N, Krutyeva M, Radulescu A, Pyckhout-Hintzen W, Grizzuti N. The role of the binding salt sodium salicylate in semidilute ionic cetylpyridinium chloride micellar solutions: a rheological and scattering study. Phys Chem Chem Phys 2017; 19:782-790. [DOI: 10.1039/c6cp06964a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The viscosity varies as a consequence of binding, first, and screening, later, action of the penetrating salt.
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Affiliation(s)
- D. Gaudino
- DICMaPI
- Università degli Studi di Napoli Federico II
- 80125 Napoli
- Italy
| | - R. Pasquino
- DICMaPI
- Università degli Studi di Napoli Federico II
- 80125 Napoli
- Italy
| | - J. Stellbrink
- Jülich Centre for Neutron Science JCNS (JCNS-1)
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | - N. Szekely
- Jülich Centre for Neutron Science outstation at MLZ
- 85747 Garching
- Germany
| | - M. Krutyeva
- Jülich Centre for Neutron Science JCNS (JCNS-1)
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | - A. Radulescu
- Jülich Centre for Neutron Science outstation at MLZ
- 85747 Garching
- Germany
| | - W. Pyckhout-Hintzen
- Jülich Centre for Neutron Science JCNS (JCNS-1)
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | - N. Grizzuti
- DICMaPI
- Università degli Studi di Napoli Federico II
- 80125 Napoli
- Italy
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39
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Wang P, Pei S, Wang M, Yan Y, Sun X, Zhang J. Coarse-grained molecular dynamics study on the self-assembly of Gemini surfactants: the effect of spacer length. Phys Chem Chem Phys 2017; 19:4462-4468. [DOI: 10.1039/c6cp07690d] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
This work provides a molecular-level understanding of the underlying mechanism of the self-assembly of Gemini surfactants.
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Affiliation(s)
- Pan Wang
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Shuai Pei
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Muhan Wang
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Youguo Yan
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
| | - Xiaoli Sun
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
| | - Jun Zhang
- College of Science
- China University of Petroleum
- 266580 Qingdao
- People's Republic of China
- Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong
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40
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Jeżewski W. Effect of long-range interactions on nanoparticle-induced aggregation. Phys Chem Chem Phys 2016; 18:22929-36. [PMID: 27485887 DOI: 10.1039/c6cp04490e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The process of attaching liquid media molecules to dispersed nanoparticles is studied by numerically investigating the time evolution of the size distribution of the emerging aggregates. Within the considered mechanism of aggregation, both the primary particles and the resulting aggregates are assumed to connect freely dispersing molecules, but the particles and aggregates are not allowed to self-link or self-assemble at each evolution stage of the system, due to, e.g., repulsive interactions. The process of random attachment of dispersing molecules to immersed nanoparticles and aggregates is considered to be driven by attractive long-range interactions of the van der Waals type. The molecule binding rate is, in consequence, modeled as being dependent not only on the size and surface morphology of the existing aggregates, but also on the van der Waals forces, whose strength is itself treated as dependent on the aggregate size. It is demonstrated that these forces diminish, in general, the inhomogeneity of aggregate size. Such an effect is shown to be especially distinct when the interaction strength is relatively large but does not increase as aggregates increase in size, i.e., when strongly attracted media molecules functionalize the resultant aggregates to prevent the increase of the interaction strength. This result can be helpful to construct stable complex substances containing aggregates with low size dispersion. Surprisingly, the evolution of aggregating systems toward more significant inhomogeneity takes place when the interaction strength is initially large and increases fast enough with the size of aggregates.
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Affiliation(s)
- Wojciech Jeżewski
- Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland.
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41
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Johnston MA, Swope WC, Jordan KE, Warren PB, Noro MG, Bray DJ, Anderson RL. Toward a Standard Protocol for Micelle Simulation. J Phys Chem B 2016; 120:6337-51. [DOI: 10.1021/acs.jpcb.6b03075] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - William C. Swope
- IBM Almaden Research Center, San Jose, California, United States
| | - Kirk E. Jordan
- IBM T.J. Watson Research, Cambridge, Massachusetts, United States
| | | | - Massimo G. Noro
- Unilever R&D Port Sunlight, Quarry Road East, Bebington, Wirral, CH63 3JW, U.K
| | - David J. Bray
- STFC
Hartree Centre, SciTech Daresbury, Warrington, Cheshire WA4
4AD, U.K
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Sambasivam A, Sangwai AV, Sureshkumar R. Self-Assembly of Nanoparticle-Surfactant Complexes with Rodlike Micelles: A Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:1214-1219. [PMID: 26760445 DOI: 10.1021/acs.langmuir.5b03689] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The self-assembly of nanoparticles (NPs) with cationic micelles of cetyltrimethylammonium chloride (CTAC) is known to produce stable nanogels with rich rheological and optical properties. Coarse-grained molecular dynamics (MD) simulations are performed to explore the molecular mechanisms underlying this self-assembly process. In an aqueous solution of CTAC surfactants, a negatively charged NP with a zeta potential of less than -45 mV is observed to form a stable vesicular structure in which the particle surface is almost entirely covered with a double layer of surfactants. In comparison, surfactants form a monolayer, or a corona, around an uncharged hydrophobic NP with the tailgroups physically adsorbed onto the particle. In the presence of sodium salicylate salt, such NP-surfactant complexes (NPSCs) interact with rodlike CTAC micelles, resulting in the formation of stable junctions through the opening up of the micelle end-cap followed by surfactant exchange, which is diffusion-limited. The diffusive regime spans several hundred nanoseconds, thereby necessitating MD simulations over microsecond time scales. The energetics of NPSC-micelle complexation is analyzed from the variation in the total pair-potential energy of the structures.
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43
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Dhakal S, Sureshkumar R. Uniaxial Extension of Surfactant Micelles: Counterion Mediated Chain Stiffening and a Mechanism of Rupture by Flow-Induced Energy Redistribution. ACS Macro Lett 2015. [DOI: 10.1021/acsmacrolett.5b00761] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Subas Dhakal
- Department of Biomedical and Chemical Engineering and ‡Department of Physics, Syracuse University, Syracuse, New York 13244, United States
| | - Radhakrishna Sureshkumar
- Department of Biomedical and Chemical Engineering and ‡Department of Physics, Syracuse University, Syracuse, New York 13244, United States
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