Molecular Structure and Dynamics in Thin Water Films at the Silica and Graphite Surfaces

Journal Article · Tue Jan 01 00:00:00 EST 2008 · Journal of Physical Chemistry C

DOI:https://doi.org/10.1021/jp803234a· OSTI ID:1021958

Argyris, Dr. Dimitrios ^[1]; Tummala, Dr. Naga Rajesh ^[1]; Cole, David R ^[2]

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1. University of Oklahoma
2. ORNL

The structure and dynamic properties of interfacial water at the graphite and silica solid surfaces were investigated using molecular dynamics simulations. The effect of surface properties on the characteristics of interfacial water was quantified by computing density profiles, radial distribution functions, surface density distributions, orientation order parameters, and residence and reorientation correlation functions. In brief, our results show that the surface roughness, chemical heterogeneity, and surface heterogeneous charge distribution affect the structural and dynamic properties of the interfacial water molecules, as well as their rate of exchange with bulk water. Most importantly, our results indicate the formation of two distinct water layers at the SiO2 surface covered by a large density of hydroxyl groups. Further analysis of the data suggests a highly confined first layer where the water molecules assume preferential hydrogen-down orientation and a second layer whose behavior and characteristics are highly dependent on those of the first layer through a well-organized hydrogen bond network. The results suggest that water-water interactions, in particular hydrogen bonds, may be largely responsible for macroscopic interfacial properties such as adsorption and contact angle.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1021958
• Journal Information: Journal of Physical Chemistry C, Vol. 112, Issue 35; ISSN 1932--7447
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
ADSORPTION
BEHAVIOR
CHARGE DISTRIBUTION
CORRELATION FUNCTIONS
DENSITY
MOLECULAR DYNAMICS METHOD
FILMS
FUNCTIONS
GRAPHITE
HYDROGEN
INTERACTIONS
LAYERS
MOLECULAR STRUCTURE
MOLECULES
ORDER PARAMETERS
ORIENTATION
ROUGHNESS
SILICA
SIMULATION
SOLIDS
SPATIAL DISTRIBUTION
SURFACE PROPERTIES
SURFACES
WATER