Simulating the effect of liquids and gases on films

 I'm interested in examining the structure and self-assembly of multilayer
 films using molecular mechanics.  Unfortunately, the structure of these
 films - often their existance - depends on the presence of a liquid or gas
 medium which helps to hold the film onto the substrate even if it is not
 incorporated into the film.  A trivial example would be Langmuir-Blodget
 films of stearic acid on aluminum.  In air a multilayer film is stable for
 months.  When the sample is introduced to vacuum, all but the layer directly
 attached to the aluminum rapidly sublimate from the surface.
 To study the self assembly of a monolayer film at the solid-liquid interface
 one properly needs to incorporate the liquid itself.  However, the inclusion
 of the liquid molecules rapidly drives the computational effort through the
 roof.  It seems to me that it ought to be possible to simulate the effect of
 the liquid by a viscous damping term, possibly only applied to atoms on the
 solvent accessible surface of a molecule.  Has anyone looked at handling
 this problem in this kind of way or have any comments to make on whether
 they think this kind of approach would be feasible?
 Dr. Ross Underhill
 Royal Military College of Canada
 Kingston, Ontario
 K7K 5L0
 (613) 541-6000 X6175