Lattice fluid self-consistent field theory

Peck DG, Johnston KP. Lattice fluid self-consistent field theory of surfaces with anchored chains. Macromolecules 1993 26 1537. 

The unique density dependence of fluid properties makes supercritical fluids attractive as solvents for colloids including microemulsions, emulsions, and latexes, as discussed in recent reviews[l-4]. The first generation of research involving colloids in supercritical fluids addressed water-in-alkane microemulsions, for fluids such as ethane and propane[2, 5]. The effect of pressure on the droplet size, interdroplet interactions[2] and partitioning of the surfactant between phases was determined experimentally[5] and with a lattice fluid self-consistent field theory[6]. The theory was also used to understand how grafted chains provide steric stabilization of emulsions and latexes. 

Peck, D. G. and Johnston, K. P. (1993) Prediction of interfacial properties in microemulsions The lattice fluid self-consistent field theory, J. Phys. Chem. 5661-67. 

Quantitative predictions of surfactant phase behavior can be made by constructing a thermodynamic model. The classical expression for the free energy of a microemulsion is a function of the interfacial tension, bending moment, and micelle-micelle interactions [47]. Two quantitative models have been developed to describe supercritical microemulsions based on this concept. Here, the key challenge is to find accurate expressions for the oil-surfactant tail interactions and the tail-tail interactions. To do this, the first model uses a modified Flory-Krigbaum theory [43,44], and the second a lattice fluid self-consistent field (SCF) theory [25]. 

Molecular-based theories are useful for developing rational stabilizer design criteria and investigating the correlation with bulk phase behavior for stabilizers in supercritical fluids. Molecular theories of polymer adsorption, such as the lattice self-consistent field (SCF) theory of Scheutjens and Fleer[69], allow chain structure, adsorption energy, solubility, length, and concentration to be varied independently. Simulation, while more computationally intensive, offers the additional advantages of... 

With realizations of the Vycor glass as shown in Fig. 1, mean field theory applied to the lattice model (1) provides a simple and sufficiently realistic method to examine fluid adsorption behavior on a coarse-grained level. In particular, the local density on each site pi = (riitj) is self-consistently determined by... 

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