CONICET | Buscador de Institutos y Recursos Humanos

Molecular dynamics simulations have been carried out to investigatethe structure and dynamics of liquid methanol confined in3.3~nm diameter, cylindrical silica pores.Three cavities, differing in the characteristics of the functional groupsat their walls have been examined:(i) smooth hydrophobic pores, in whichdispersive forces prevail;(ii) hydrophilic cavities, with surfaces covered by polar silanol groups,and(iii) a much more rugged pore, in which 60\%\ of the previousinterfacial hydroxyl groups were replaced by the bulkiertrimethylsilyl ones.Confinement promotes a considerable structure at the vicinityof the pore walls, which is enhanced in the case ofhydroxylated surfaces; moreover, in the presence oftrimethylsilyl groups, the propagation of thisinterface-induced spatial ordering extends down to thecentral region of the pore.Concerning the dynamical modes, we observed an overall slowdown inboth, translational and rotational motions.\, An \, analysis of these mobilities froma local perspective \, shows \, that \, the \, largest \, retardations\clearpage\noindent operate at the vicinity of the interfaces.The gross features of the rotational dynamics were analyzedin terms of contributions arising from bulk and surface states.Compared to the bulk dynamical behavior, the characteristictimescales associated with the rotational motions show themost dramatic increments.A dynamical analysis of hydrogen bond formation andbreaking processes is also included.