Molecular dynamics study of 5CB at the air-water interface: From gas to beyond the monolayer collapse

We extend our earlier fully atomistic molecular dynamics (MD) study [Gürbulak, O., and Cebe, E. (2017)] to the analysis of the interfacial behaviour of 4-n-pentyl-4′-cyanobiphenyl (5CB) at the air/water interface with surface coverages ranging from 0.07 to 5.01 molecules/nm2. The density profiles of interfacial species and simulated tilt angles lead to the alignment variation of molecules from planar to tilted with increasing surface density of 5CB that is in good accord with experiments. Order parameters of various ranks and CH bond order parameters relevant for deuterium nuclear magnetic resonance spectra were computed. The orientational order of mesogen molecules is considerably enhanced with respect to that for pure nematic 5CB, and increases also with surface density. The calculated interfacial thickness, monolayer width, and radial distribution functions were compared with previously reported results.