Surface tension

About: Surface tension is a research topic. Over the lifetime, 25410 publications have been published within this topic receiving 695471 citations.

Colloid science: non-spherical bubbles.

Abstract: Surface tension gives gas bubbles their perfect spherical shape by minimizing the surface area for a given volume. Here we show that gas bubbles and liquid drops can exist in stable, non-spherical shapes if the surface is covered, or 'armoured', with a close-packed monolayer of particles. When two spherical armoured bubbles are fused, jamming of the particles on the interface supports the unequal stresses that are necessary to stabilize a non-spherical shape.

Elastocapillarity: Surface Tension and the Mechanics of Soft Solids

Abstract: It is widely appreciated that surface tension can dominate the behavior of liquids at small scales. Solids also have surface stresses of a similar magnitude, but they are usually overlooked. However, recent work has shown that these can play a central role in the mechanics of soft solids such as gels. Here, we review this emerging field. We outline the theory of surface stresses, from both mechanical and thermodynamic perspectives, emphasizing the relationship between surface stress and surface energy. We describe a wide range of phenomena at interfaces and contact lines where surface stresses play an important role. We highlight how surface stresses cause dramatic departures from classic theories for wetting (Young–Dupre), adhesion (Johnson–Kendall–Roberts), and composites (Eshelby). A common thread is the importance of the ratio of surface stress to an elastic modulus, which defines a length scale below which surface stresses can dominate.

Thermodynamic Origin of Hofmeister Ion Effects

Abstract: Quantitative interpretation and prediction of Hofmeister ion effects on protein processes, including folding and crystallization, have been elusive goals of a century of research. Here, a quantitative thermodynamic analysis, developed to treat noncoulombic interactions of solutes with biopolymer surface and recently extended to analyze the effects of Hofmeister salts on the surface tension of water, is applied to literature solubility data for small hydrocarbons and model peptides. This analysis allows us to obtain a minimum estimate of the hydration b1 (H2O A−2), of hydrocarbon surface and partition coefficients Kp, characterizing the distribution of salts and salt ions between this hydration water and bulk water. Assuming that Na+ and SO42− ions of Na2SO4 (the salt giving the largest reduction in hydrocarbon solubility as well as the largest increase in surface tension) are fully excluded from the hydration water at hydrocarbon surface, we obtain the same b1 as for air-water surface (∼0.18 H2O A−2). Ran...

Topological defects in dispersed words and worlds around liquid crystals, or liquid crystal drops

Abstract: The structure of dispersed liquid crystal droplets elasticity, surface tension, and surface anchoring. For sufficiently large droplets with radius R K / W a, where K is the bulk elastic constant and W a is the anchoring coefficient, the surface terms prevail. As a result, the equilibrium states of large droplets contain topologically stable defects. Application of topological theorems to and hedgehogs is reviewed. is controlled by a balance of the bulk defect structures, e.g. monopoles, boojums

Computer Simulation of Hydrophobic Hydration Forces on Stacked Plates at Short Range

Abstract: The potential of mean force between two large parallel hydrophobic oblate ellipsoidal plates in liquid water is determined by molecular dynamics Each ellipsoid displaces approximately 40 water molecules and has major and minor axes of 31 and 93 A, respectively, has a surface area of 650 A*, and interacts repulsively with the solvent water molecules The potential of mean force is calculated from thermodynamic perturbation theory for a series of decreasing plate separations, using constant-pressure molecular dynamics As the plates are moved together, they are first separated by three water layers and then by two, but for shorter distances, a dewetting transition occurs, and one water layer is never observed despite the fact that one can fit As the plates are brought together, there is a corresponding weak oscillation in the potential of mean force corresponding to the removal of each water layer until the dewetting transition takes place, and for closer separations, the surrounding water molecules induce a constant average attractive force of 25 (kJ/mol)/A between the plates This hydrophobic attraction is largely entropic in character, and the potential of mean force is found to be proportional to the area of the water-vacuum surface in this dewetting regime The constant of proportionality is found to be smaller than the gas-liquid surface tension of the water model used There is a very strong short-range driving force toward contact pairing