Polarization model for poorly-organized interfacial water: Hydration forces between silica surfaces

On possible microscopic origins of the swelling of neutral lipid bilayers induced by simple salts

“…Since it is obvious that the lipid bilayers undulate thermally (otherwise, their anomalous swelling or their unbinding cannot be explained), it is impossible for the water molecules to remain organized in ice-like layers near the undulating bilayers. A model involving the assumption of a totally random orientation of water molecules, proposed recently [20], indicates that the correlation length might become in this case as low as λ m = 6.27 ε Å, where ε is the dielectric constant for the screening of the interactions between neighboring atoms (much lower than the bulk dielectric constant of water, ε = 80). A value λ m = 4 Å has been shown to represent well the hydration forces between silica surfaces [20].…”

“…A model involving the assumption of a totally random orientation of water molecules, proposed recently [20], indicates that the correlation length might become in this case as low as λ m = 6.27 ε Å, where ε is the dielectric constant for the screening of the interactions between neighboring atoms (much lower than the bulk dielectric constant of water, ε = 80). A value λ m = 4 Å has been shown to represent well the hydration forces between silica surfaces [20]. However, a low value for λ m still does not provide a viable solution for the interactions between neutral lipid bilayers; indeed, for λ m = 4 Å, the free energy decreases sufficiently rapid in the vicinity of the surface (Fig.…”

“…3b the exponential free energy of hydration derived in Ref. [13] to fit the experiments on lipid bilayers (namely, f hyd (z) = 0.0336 exp(− z 2.1 ) J/m 2 is compared with an exponential "hydration force" employed recently, f hyd (z) = 0.00053 exp(− z 5.4 ) J/m 2 [20] to fit the experiments on the interactions between silica surfaces [21]. The later surfaces are known for their strong hydration interactions; silica colloids typically do not coagulate, regardless of the ionic strength.…”

Combined Electrospray-Scanning Mobility Particle Sizer (ES-SMPS) and Time-Resolved Synchrotron Radiation-Small-Angle X-ray Scattering (SR-SAXS) Investigation of Colloidal Silica Aggregation. Part II. Influence of Aggregation Initiator on Gel Stability

“…7,8,15,16 It follows that structure-breaker ions adsorb more strongly on a structure-breaker surface and vice versa. It has been suggested that the silica surface is of structure-breaker type, 8,18 but the precise structure of the silicaÀwater interface is not known, and more importantly it varies with pH. 16 The ion specific effects can be explained theoretically by including both the ionÀsurface hydration interaction and the ionÀion and ionÀsurface dispersion interactions.…”

Density Functional Theory Study of Water Molecule Adsorption on the α-Quartz (001) Surface with and without the Presence of Na+, Mg2+, and Ca2+

“…Mineral hydration in aqueous solution has been extensively studied using SFA, , X-ray diffraction, , transmission electron microscopy, NMR, , atomic force microscopy (AFM), and other experimental methods. − Referring to the hydration model, Manciu et al , proposed a polarization strategy, wherein an “ice-like” hydration layer structure appeared on the quartz surface in aqueous solution. The mineral’s hydration layer is characterized by its elasticity and strength, and the water molecules in this region have larger density and viscosity when compared to bulk water. − The thickness of the hydration layer on the silica surface was measured using two methods, namely, viscosity and AFM .…”