(216k) Diffusion of n-Alkanols With in Self-Assembled Monolayer On Mica Surface: A Molecular Dynamics Study

Hydrophobicity or hydrophilicity of surface greatly induces the orientation of amphiphilic molecules and give rise to different types of pattern on the surface which is also called as self-assembled layer. In this study, self-assembled mono layer of n-alkanols on mica surface has been investigated with the help of molecular dynamics simulations. In particular, we have investigated the effect of chain length of n-alkanols on the self-assembly and layering of n-alkanols on the surface as well as the surface diffusion of the n-alkanols with in the monolayer. This work provides some insight and clarifies the assumption of tilted n-alkanols monolayer on mica surface irrespective of the chain length and the ordering of the n-alkanols with in the layer. Under varying density of n-alkanols with in monolayer, the orientation profile of the molecules change, at the same time, transition from solid-like structure to liquid-like structure is also observed from the radial distribution function. This transition also ensures strong attractive force between surface and alkanols and hence strong hydrogen bonding. The isotherm typically follows Langmuir adsorption isotherm. Study of the nature of the surface diffusion of alkanols is found to be most interesting. We have tried to correlate the surface diffusion of alkanols with hydrogen bonding, both intermolecular as well as with surface.