Computer simulation of Langmuir-Blodgett films

Abstract

The computer simulation has been applied to predict the structure and dynamics of a Langmuir-Blodgett film of a stearic acid with three molecular models. The energy minimisation has been used to reveal the structure of the film at ground state(0 K). The minimium energy structure of the film is not so sentive to the molecular model for the molecular tilt but shows the big difference in the behaviour of the minimum energy as a function of molecular area. The incorporation of electrostatic interaction does not have significant effect on the minimum energy structure since Van der Waals interaction between chains dominates the overall structure of the film. In the molecular dynamics calculation, the explicit-hydrogen model predicts that the monolayer with A_{m =} 20.8A*² has a negligible molecular tilt and the monolayer with A_{m =} 21.2A*² has a molecular tilt of 9^o. The layer has co-operative molecular motion between the molecular tilt and the azimuthal orientation of the layer because of relatively small molecular tilt. The all-atom model including electrostatic interaction predicts the molecular tilt of 18.8^o for the layer with A_{m =} 21.2A*², which is more than twice the molecular tilt of the simulation using the explicit-hydrogen model. The dipolar interaction in the layer with the all-atom model has a role to determine the detailed molecular orientation of the layer. The bilayer with the all-atom model shows the strong correlation of the structures between the first layer and the second layer since there is very strong electrostatic interaction between layers.

More information

Identifiers

Catalogue record

Export record

ASCII CitationAtomBibTeXData Cite XMLDublin CoreDublin CoreEP3 XMLEndNoteHTML CitationHTML CitationHTML ListJSONMETSMODSMPEG-21 DIDLOpenURL ContextObjectOpenURL ContextObject in SpanRDF+N-TriplesRDF+N3RDF+XMLRIOXX2 XMLReferReference ManagerSimple Metadata