2010/05/13 by Pradeep Kumar, Kumar, Pradeep
Chemistry · Engineering · Physics and Astronomy · #Electrostatics and Colloid Interactions #FOS: Physical sciences #Nanopore and Nanochannel Transport Studies #Soft Condensed Matter (cond-mat.soft) #Spectroscopy and Quantum Chemical Studies
paper · pdf · doi:10.48550/arxiv.1005.2380
openalex publication_date 2010/05/13 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
Using molecular dynamics simulations we study the dynamics of a water-like\nTIP5P model of water in hydrophilic and hydrophobic confinement. We find that\nin case of extreme nanocofinement such that there is only one molecular layer\nof water between the confinement surface, the dynamics of water remains\nArrhenius with a very high activation energy up to high temperatures. In case\nof polar (hydrophilic) confinement, The intermediate time scale dynamics of\nwater is drastically modified presumably due to the transient coupling of\ndipoles with the effective electric field due to the surface charges.\nSpecifically, we find that in the presence of the polar surfaces, the dynamics\nof monolayer water shows anomalous region -- namely the lateral mean square\ndisplacement displays a distinct superdiffusive intermediate time scale\nbehavior in addition to ballistic and diffusive regimes. We explain these\nfinding by proposing a simple model. Furthermore, we find that confinement and\nthe surface polarity changes the vibrational density of states specifically we\nsee the enhancement of the low frequency collective modes in confinement\ncompared to bulk water. Finally, we find that the length scale of\ntranslational-orientational coupling increases with the strength of the\npolarity of the surface.\n