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Temperature-sensitive colloidal phase behavior induced by critical Casimir forces

We report Monte Carlo simulations of phase behavior of colloidal suspensions with near-critical binary solvents using effective pair potentials from experiments. At off-critical solvent composition, the calculated phase diagram agrees well with measurements of the experimental system, indicating that many-body effects are limited. Close to the critical composition, however, agreement between experiment and sim...

Cooperative slowdown of water rotation near densely charged ions is intense but...

Accepted manuscript version ; We investigate the reorientation dynamics of water at 300 K in solutions of magnesium sulfate and cesium chloride from classical atomistic molecular dynamics simulations using the “simple water model with four sites and negative Drude polarizability” (SWM4-NDP) and accompanying ion models; for SO2− 4 , we derive SWM4-NDPcompatible parameters. Results indicate that pairs of ions ha...

Single pairs of densely charged anions and cations cooperatively slowdown water...

We use classical atomistic molecular dynamics simulations and polarizable models to investigate the dynamics of rotation of water in the vicinity of single pairs of magnesium sulfate or cesium chloride ions at varying anion-cation separation. At an anion-cation separation of 23 Å, a distance sufficiently large that each ion can be considered isolated, we find that the four ions impact the rotational dynamics of...

Dynamics of water of hydration near disaccharides strongly depends on solute to...

comunicação em poster ; Disaccharides such as trehalose are abundant components of cells and may alter the phase behavior or dynamics of phospholipid bilayers: for example, trehalose is a cryoprotectant of lipid bilayers. The origin of this and other effects of disaccharides on membranes is still under debate. One possibility is that some disaccharides alter the dynamics of water of hydration relative to the b...

Statics and dynamics of free and hydrogen-bonded OH groups at the air/water int...

We use classical atomistic molecular dynamics simulations of two water models (SPC/E and TIP4P/2005) to investigate the orientation and reorientation dynamics of two subpopulations of OH groups belonging to water molecules at the air/water interface at 300 K: those OH groups that donate a hydrogen bond (called “bonded”) and those that do not (called “free”). Free interfacial OH groups reorient in two distinct r...

Adsorption of homopolypeptides on gold investigated using atomistic molecular ...

We investigate the role of dynamics on adsorption of peptides to gold surfaces using all-atom molecular dynamics simulations in explicit solvent. We choose six homopolypeptides [Ala 10 , Ser 10 , Thr 10 , Arg 10 , Lys 10 , and Gln 10 ], for which experimental surface coverages are not correlated with amino acid level affinities for gold, with the idea that dynamic properties may als...

Disaccharide topology induces slow down in local water dynamics

Molecular level insight into water structure and structural dynamics near proteins, lipids and nucleic acids is critical to the quantitative understanding of many biophysical processes. Un- fortunately, understanding hydration and hydration dynamics around such large molecules is challenging because of the necessity of deconvoluting the effects of topography and chemical heterogeneity. Here we study, via classi...

Comment on “Principal role of the stepwise aggregation mechanism in ionic surfa...

Ultrafast reorientation of dangling OH groups at the air-water interface using ...

We report the real-time measurement of the ultrafast reorientational motion of water molecules at the water-air interface, using femtosecond time- and polarization-resolved vibrational sum-frequency spectroscopy. Vibrational excitation of dangling OH bonds along a specific polarization axis induces a transient anisotropy that decays due to the reorientation of vibrationally excited OH groups. The reorientation ...

Disaccharide topology induces slow down in local water dynamics

We investigate the structure and dynamics of water around disaccharides Kojibiose and Trehalose using classical atomistic molecular dynamics simulations and transition state theory. Results highlight that hydrophobicity and water dynamics are related. Identical sugar functional groups may have drastically different hydrophobicities and their neighboring water drastically different dynamics if in different place...