0000000000541973
AUTHOR
Harald Lange
Monte Carlo Simulation of Langmuir Monolayer Models
We study a coarse grained, continuum model for Langmuir monolayers, i.e., monolayers of amphiphilic molecules on a polar substrate. The amphiphiles are represented by stiff chains of beads with one end grafted to a planar surface. Monte Carlo Simulations at constant pressure have been performed, using simulation boxes of variable size and variable shape. A number of techniques have been explored in order to obtain an efficient simulation algorithm. We discuss the resulting phase diagram, characterize the different phases, and analyze the conditions, under which they can be found.
Surface anchoring on liquid crystalline polymer brushes
We present a Monte Carlo study of the surface anchoring of a nematic fluid on swollen layers of grafted liquid crystalline chain molecules. The liquid crystalline particles are modeled by soft repulsive ellipsoids, and the chains are made of the same particles. An appropriately modified version of the configurational bias Monte Carlo algorithm is introduced, which removes and redistributes chain bonds rather than whole monomers. With this algorithm, a wide range of grafting densities could be studied. The substrate is chosen such that it favors a planar orientation (parallel to the surface). Depending on the grafting density, we find three anchoring regimes: planar, tilted, and perpendicula…
Theoretical modeling of Langmuir monolayers
Abstract We study coarse-grained continuum models for Langmuir monolayers by self-consistent field theory and by Monte Carlo simulations. Amphiphilic molecules are represented by stiff chains of monomers with one end grafted to a planar surface. In particular, we discuss the origin of successive fluid–fluid transitions, the possible origin of tilt order and the factors which determine the direction of tilt.