IFLYSIB   05383
INSTITUTO DE FISICA DE LIQUIDOS Y SISTEMAS BIOLOGICOS
Unidad Ejecutora - UE
artículos
Título:
Water behavior in the neighborhood of hydrophilic and hydrophobic membranes: Lessons from molecular dynamics simulations
Autor/es:
CHARA OSVALDO; MCCARTHY ANDRÉS NORMAN; FERRARA, CG; CAFFARENA, ERNESTO RAÚL; GRIGERA JOSÉ RAÚL
Revista:
PHYSICA A - STATISTICAL AND THEORETICAL PHYSICS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam, Netherlands; Año: 2009 vol. 388 p. 4551 - 4559
ISSN:
0378-4371
Resumen:
The study of properties of water in the vicinity of surfaces poses a fascinating challenge.In this article we studied the behavior of water molecules in the neighborhood ofmembranes. We addressed the question of how these water molecules are influenced bythe membranes' hydrophilicity. Three systems were studied through molecular dynamicssimulations: water in the presence of a hydrophilic membrane (PL), water in the presenceof a hydrophobic (PB) one and water in the absence of membranes (BULK). Additionally,in order to study the dependence of the effect of the membrane on the behavior ofneighboring water molecules with temperature, each system was simulated at threedifferent temperatures (K): 250, 300 and 350. For each condition, kinetic and structuralfeatures were studied. The first feature involved the calculation of diffusion coefficients andactivation energy. The second feature was evaluated through the study of water densityand hydrogen bond distribution. From the present study we concluded that: (1) densitystudies underestimate the influence of both hydrophilic and hydrophobic membraneson the neighboring water molecules; (2) the hydrophilic and hydrophobic membranesdisturb the hydrogen bond network within distances ranging from 1 to 8 nm, dependingon the nature of the membrane and the temperature conditions; (3) the presence of ahydrophobic surface results in an enhancement of the natural hydrogen bond networkpresent in liquid water, to a greater extent than what even an ordered Ih ice structure isable to achieve (i.e. PL membrane); (4) the structural enhancement due to the presence ofa hydrophobic surface involves roughly 18 to 24 water hydration layers, for ambient andabove temperature conditions.