Molecular simulation of water confined in nanoporous silica

被引:153
作者
Bonnaud, P. A. [1 ,2 ]
Coasne, B. [3 ]
Pellenq, R. J-M [1 ,2 ,4 ]
机构
[1] CNRS, Ctr Interdisciplinaire Nanosci Marseille, F-13288 Marseille 9, France
[2] Aix Marseille Univ, F-13288 Marseille 9, France
[3] Univ Montpellier 2, Inst Charles Gerhardt Montpellier, F-34095 Montpellier 5, France
[4] MIT, Dept Civil & Environm Engn, Cambridge, MA 02139 USA
关键词
MONTE-CARLO-SIMULATION; PORE STRUCTURE CHARACTERIZATION; CAPILLARY CONDENSATION; NEUTRON-DIFFRACTION; POROUS SILICA; COMPUTER-SIMULATION; MESOPOROUS SILICA; PHASE-EQUILIBRIA; SELF-DIFFUSION; DYNAMICS SIMULATIONS;
D O I
10.1088/0953-8984/22/28/284110
中图分类号
O469 [凝聚态物理学];
学科分类号
070205 ;
摘要
This paper reports on a molecular simulation study of the thermodynamics, structure and dynamics of water confined at ambient temperature in hydroxylated silica nanopores of a width H = 10 and 20 A. The adsorption isotherms for water in these nanopores resemble those observed for experimental samples; the adsorbed amount increases continuously in the multilayer adsorption regime until a jump occurs due to capillary condensation of the fluid within the pore. Strong layering of water in the vicinity of the silica surfaces is observed as marked density oscillations are observed up to 8 A from the surface in the density profiles for confined water. Our results indicate that water molecules within the first adsorbed layer tend to adopt a H-down orientation with respect to the silica substrate. For all pore sizes and adsorbed amounts, the self-diffusivity of confined water is lower than the bulk, due to the hydrophilic interaction between the water molecules and the hydroxylated silica surface. Our results also suggest that the self-diffusivity of confined water is sensitive to the adsorbed amount.
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页数:15
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