in a condensed phase state dispersed in a continuous liquid-expanded phase. Simple and wide used models for biological membranes are the Langmuir monolayers, which have the possibility to change their composition and phase state in a very controlled manner.
For neutral lipids, the interdomain interactions are of dipolar nature. ``Usually'' domains are modeled as point dipoles with excluded area interactions. This approximation disregards the fact that the ``effective'' dipolar interaction arises from the dipolar surface densities carried by the lipids inside the domains, and thus is a good model only for large interdomain distances and small domains.
In this work we investigated the structure, dynamics and rheology of inhomogeneous monolayer at the air/water interface. For this purpose we implemented brownian dynamics simulations taking into account the surface dipolar density interactions, and we performed experiments with mixed monolayers at different proportions of distearoylphosphatidylcholine (DSPC) and dimyristoylphosphatidylcholine (DMPC).
We studied the pair correlation function, self-diffusion coefficient and surface shear viscosity as a function of the condensed area fraction, and the range validity of the point dipole approximation.
