Molecular Dynamics Simulations of Mixed Cationic/Anionic Wormlike Micelles

Yakovlev, D. S.; Boek, Edo S.

doi:10.1021/la063268y

Cited by 44 publications

(46 citation statements)

References 25 publications

(47 reference statements)

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“…Surprisingly little simulation work has addressed coupled aggregation and LC order. Some papers have focused on the molecular details that promote aggregate formation in specific systems and considered single aggregates [67][68][69][70][71][72]. Simulating larger systems of interacting aggregates is too computationally costly for atomistic simulation and coarse-grained models are required.…”

Section: Introductionmentioning

confidence: 99%

Linear aggregation and liquid-crystalline order: comparison of Monte Carlo simulation and analytic theory

2010

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Many soft-matter and biophysical systems are composed of monomers which reversibly assemble into rod-like aggregates. The aggregates can then order into liquid-crystal phases if the density is high enough, and liquid-crystal ordering promotes increased growth of aggregates. Systems that display coupled aggregation and liquid-crystal ordering include wormlike micelles, chromonic liquid crystals, DNA and RNA, and protein polymers and fibrils. Coarse-grained molecular models that capture key features of coupled aggregation and liquid-crystal ordering common to many different systems are lacking; in particular, the role of monomer aspect ratio and aggregate flexibility in controlling the phase behavior are not well understood. Here we study a minimal system of sticky cylinders using Monte Carlo simulations and analytic theory. Cylindrical monomers interact primarily by hard-core interactions but can stack and bind end to end. We present results for several different cylinder aspect ratios and a range of end-to-end binding energies. The phase diagrams are qualitatively similar to those of chromonic liquid crystals, with an isotropic-nematic-columnar triple point. The location of the triple point is sensitive to the monomer aspect ratio.We find that the aggregate persistence length varies with temperature in a way that is controlled by the interaction potential; this suggests that the form of the interaction potential affects the phase behavior of the system. Our analytic theory shows improvement compared to previous theory in quantitatively predicting the I-N transition for relatively stiff aggregates, but requires a better treatment of aggregate flexibility. arXiv:1007.4530v1 [cond-mat.soft]

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Section: Introductionmentioning

confidence: 99%

Linear aggregation and liquid-crystalline order: comparison of Monte Carlo simulation and analytic theory

2010

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“…Various theoretical models have been given and used to interpret the experimental results of binary combinations [3][4][5][6][7][8][9][10][11][12][13][14]. Mixed micelles formed by surfactant combinations such as nonionic/nonionic [15,16], anionic/nonionic [17,18], cationic/nonionic [16,19], cationic/anionic [20][21][22], cationic/cationic [19,23] and anionic/anionic [16,18] have been studied in detail by several workers. Now-a-days gemini surfactants are gaining wide attention as these surfactants are much more surface active compared to their * Corresponding author.…”

Section: Introductionmentioning

confidence: 99%

Studies of mixed micelle formation between cationic gemini and cationic conventional surfactants

Azum

Naqvi

Akram

et al. 2008

Journal of Colloid and Interface Science

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“…The aim of work [54] was to study the molecular structure of a wormlike mixed micelle of cationic and anionic surfactants containing hydrophobic radicals of different lengths by atomistic MD simulation. This was necessary for understanding the rheological prop erties of solutions of such micelles, which are charac terized by exclusively high viscosities.…”

Section: Cylindrical Aggregatesmentioning

confidence: 99%

Computer simulations of micellar systems

Brodskaya

2012

Colloid J

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LINTRODUCTIONMicelles, which represent nanosized aggregates formed from amphiphilic molecules in solutions, are, at present, being intensely investigated by different chemical and physical methods. Surfactants, block copolymers, and biomolecules are typical amphiphilic compounds. These compounds are distinguished by the presence of spatially separated polar and nonpolar moieties in their molecule, which differently interact with solvent molecules and predetermine the ability of the compounds to aggregate in solutions. Aggregates formed in solutions are characterized by diverse shapes and sizes, while their solutions are distin guished by various phase states, which, first of all, depend on the nature of a solvent, the concentration of an amphiphilic substance, and the structure of its mol ecules. So called normal and reverse micelles are formed in polar and nonpolar solvents, respectively. Researchers studying micellar solutions have to solve the following main problems:-determination of the shape and average size of micelles and the size distribution of aggregates; -description of the molecular structure of aggre gates and surrounded solutions;-estimation of the characteristics of the interac tion of aggregates with each other and with a sol vent;-investigation of the influence of different addi tives (first of all, salts) present in solvents on micelles;-revealing mechanisms that predetermine the aggregation processes and their kinetics;-determination of the domains of different phase states; and -studying the behavior of micelles in surface lay ers, including solution-solid interfaces.All of the above listed problems and a large number of other questions are solved using diverse experimen tal and theoretical methods, including the methods of molecular simulations. The latter are increasingly being employed to supplement both real experiments and theoretical approaches, especially those used to determine the molecular structure of aggregates and mechanisms of their formation. In these cases, the suppleness of the simulation methods and the possibil ity of visualization of studied objects sometimes make these methods indispensable instruments for describ ing micellar systems. However, it should be noted that, at present, computer simulations are characterized by constraints on the sizes of examined systems (several nanometers) and the times of their observation (sev eral nanoseconds), which are partly overcome by sim plifying the description of the molecular structure of studied compounds. This review is devoted to studies of micellar systems performed by the methods of molecular simulations since 2000 up to the present. This work does not pre tend to absolute completeness; however, in the opin ion of the author, it reflects the main results of using computer methods for solving the above formulated problems. Works devoted to simulations of micellar systems were first carried out using lattice models more than 20 years ago [1]. Then, using a similarly simplified description devoid of the constraints inher ent in...

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Molecular Dynamics Simulations of Mixed Cationic/Anionic Wormlike Micelles

Cited by 44 publications

References 25 publications

Linear aggregation and liquid-crystalline order: comparison of Monte Carlo simulation and analytic theory

Linear aggregation and liquid-crystalline order: comparison of Monte Carlo simulation and analytic theory

Studies of mixed micelle formation between cationic gemini and cationic conventional surfactants

Computer simulations of micellar systems

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