Exploring the Impact of Tail Polarity on the Phase Behavior of Single Component and Mixed Lipid Monolayers Using a...

Coarse-grained molecular dynamics simulations have been used to investigate the effect of dipalmitoylphosphatidylcholine (DPPC) tail group polarity on the structural and phase behavior of both single component and binary mixed monolayers using the MARTINI force field. Surface pressure-area isotherms of single component systems indicate that DPPC monolayers become more expanded as a function of increasing tail group polarity, as observed in experimental measurements in the literature. A combination of radial distribution functions and tilt angle measurements indicate that increasing tail group polarity results in the formation of increasingly disordered monolayers. For the mixed monolayer systems, the time dependence of the radial distribution function as well as average cluster size measurements indicate that phase separation takes place between components of different tail group polarity when the monolayers undergo phase transition into disordered configurations.