Micelle formation molecular dynamics simulation

A new insight into the dynamic processes in the bulk and at the surface of surfactant solutions can be seen in molecular dynamics simulations. Only now are computers sufficiently powerful that such simulations can be performed without too many simplifications. The state of the art of molecular dynamics was recently summarised by van Os Karabomi (1993), showing that complex processes such as micelle formation (Karabomi O Connell 1993), emulsion formation or solubilisation processes (Smit et al. 1993) can be simulated. Future improvements of computers and algorithms will provide a deep insight into even more complex processes connected with dynamics of interfacial phenomena, such as adsorption layer stracture and formation, effects of molecular interfacial and bulk interactions in mixed systems of surfactants and polymers. 

Molecular dynamics simulations of gemini surfactants in aqueous solutions accounted for the change of micelle shape from spheroidal to elongated upon decreasing spacer carbon number [115]. They also predicted the formation of branched thread-like micelles. Oligomeric surfactants are capable of forming such structures because the different alkyl chains of such a surfactant can take different relative orientations in the micelles. 

Abstract Amphiphilic polymers have the ability to self-assemble into supramolec-ular structures of great complexity and utility. Nowadays, molecular dynamics simulations can be employed to investigate the self-assembly of modestly sized natural and synthetic macromolecules into structures, such as micelles, worms (cylindrical micelles), or vesicles composed of membrane bilayers organized as single or multilamellar structures. This article presents a perspective on the use of large-scale computer simulation studies that have been used to xmderstand the formation of such structures and their interaction with nanoscale solutes. Advances in this domain of research have been possible due to relentless progress in computer power plus the development of so-called coarse-grained intermolecular interaction models that encode the basic architecture of the amphiphUic macromolecules of interest. 

The molecular thermodynamic theory for micelle formation has heen worked out with increasing sophistication following the pioneering work of Israelachvili, Mitchell, and Ninham.26 The most comprehensive reports on micelle formation are those of Nagarajan and Ruckenstein and of Shiloah and Blankschtein. Many other theoretical approaches have been used in recent years to account for the formation of micelles and their properties thermod3mamics of small systems, the self-consistent field lattice model, the scaled particle theory, and Monte-Carlo and molecular dynamics MD simulations. MC and DC simulations are presently much in favor due to the increased availability of fast computers. A prediction common to all these theories is that micelles represent a thermodynamically stable state and that micellar solutions are single-phase systems. Several recent results of MD and (MC) simulations are in agreement with experimental results. ... 

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