Monte Carlo Simulations Of Surfactant Self Assembly

Fully atomistic computer simulations of surfactant self-assembly are extremely challenging because of the different length scales and the associated different times scales, implying large system sizes and tediously long simulations. To overcome this, the uninteresting degrees of freedom at the atomistic level can be integrated out leading to a meso-scale model, which can span the required length and time scales with less computational burden. We use such a meso-scale model to study surfactant self-assembly and how alcohols affect this self-assembly behavior in supercritical carbon dioxide. Here the surfactants and alcohols are represented as a chain of beads where each bead represents a set of atoms. This model is implemented into lattice Monte Carlo simulations. We show that short chain alcohols act as cosurfactants by concentrating in the surfactant layer of the aggregates, strongly decreasing micellar size and increasing the number of aggregates. In contrast long chain alcohols act as cosolvents by concentrating more in the solvent and increasing the micellar size. We then focus on systematically constructing a meso-scale model that preserves the important aspects of the atomistic model, while spanning these different length and time scales. The process of constructing this meso-scale model from the corresponding atomistic model is called coarse-graining. We first explore the rigorous coarse-graining technique in which we match the partition function of the atomistic model with that of the meso-scale model. Such a rigorous procedure has the advantage that it leads to the reproduction of all the structural and thermodynamic properties of the atomistic model in the meso-scale model. We develop a procedure to calculate the rigorous 1, 2 ... N-body effective interactions using Widom's particle insertion method. We implement this rigorous procedure for a binary ArD r system, where the degrees of freedom of Ar are integrated out. We observed that the structure at.

Dynamics of Surfactant Self-Assemblies explains the dynamics of micellar equilibria, tracking surfactant exchange, and micelle formation/breakdown processes. Highlighting the structural similarities of amphiphilic block copolymers to surfactants, this volume elucidates the dynamics of more complex self-assemblies that surfactants and amphiphilic bl

Hailed as one of the key areas of nanoscience likely to shape future scientific research, self-assembly offers the most promising route to true molecular nanotechnology. Focusing on this dynamic new field, Self Assembly: The Science of Things That Put Themselves Together explores nature's self-assembly of structures, the use of it to build engineer

Keywords: coarse-graining, cosolvent, supercritical, alcohol, co2, cosurfactant, multi-scale, simulation, modeling, surfactant, self-assembly, effective potential.

This volume includes 58 contributions to the 11th International Conference on Surface and Colloid Science, a highly successful conference sponsored by the International Association of Colloid and Interface Scientists and held in Iguassu Falls, Brazil, in September 2003. Topics covered are the following: Biocolloids and Biological Applications, Charged Particles and Interfaces, Colloid Stability, Colloidal Dispersions, Environmental Colloidal Science, Interfaces and Adsorption, Nanostructures and Nanotechnology, Self-Assembly and Structured Fluids, Surfactants and Polymers, Technology and Applications, Colloids and Surfaces in Oil Production. Surface and colloid science has acquired great momentum during the past twenty years and this volume is a good display of new results and new directions in this important area.

Understanding Molecular Simulation: From Algorithms to Applications explains the physics behind the "recipes" of molecular simulation for materials science. Computer simulators are continuously confronted with questions concerning the choice of a particular technique for a given application. A wide variety of tools exist, so the choice of technique requires a good understanding of the basic principles. More importantly, such understanding may greatly improve the efficiency of a simulation program. The implementation of simulation methods is illustrated in pseudocodes and their practical use in the case studies used in the text. Since the first edition only five years ago, the simulation world has changed significantly -- current techniques have matured and new ones have appeared. This new edition deals with these new developments; in particular, there are sections on: Transition path sampling and diffusive barrier crossing to simulaterare events Dissipative particle dynamic as a course-grained simulation technique Novel schemes to compute the long-ranged forces Hamiltonian and non-Hamiltonian dynamics in the context constant-temperature and constant-pressure molecular dynamics simulations Multiple-time step algorithms as an alternative for constraints Defects in solids The pruned-enriched Rosenbluth sampling, recoil-growth, and concerted rotations for complex molecules Parallel tempering for glassy Hamiltonians Examples are included that highlight current applications and the codes of case studies are available on the World Wide Web. Several new examples have been added since the first edition to illustrate recent applications. Questions are included in this new edition. No prior knowledge of computer simulation is assumed.