Surface tension

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

Low surface energy polystyrene

Abstract: Styrene monomers carrying C 4 F 9 and C 8 F 17 substituents were prepared and homo- and copolymerized with styrene by radical initiation. A decrease in the T g with increasing the fraction of fluorocarbon substituents was observed. Side-chain crystallization was observed for the homopolymer containing C 8 F 17 segments. This polymer exhibited a remarkably low critical surface tension by dynamic contact angle measurements, indicating the formation of a highly ordered layer of fluorocarbon degments at the polymer surface

Temperature Variation and Heat Transfer in Triangular Grooves with an Evaporating Film

Abstract: A mathematical model for the evaporating heat transfer coefe cient and temperature variation along the axial direction of a grooved plate has been developed. The model includes the effects of the capillaryinduced e ow in the grooves caused by the surface tension, the two-dimensional heat conduction occurring in the wall and liquid e lm, and the e ow and evaporation of the thin e lm caused by the disjoining pressure and surface tension in the thin e lm region. The results obtained from this model indicate that if a constant heat e ux boundary condition is applied, the heat transfer coefe cient will decrease and the wall temperature will increase along the axial direction. In addition, the apparent contact angle increases with increasing superheat, and hence, the heat transfer rate through the micro region also increases along the axial direction. Finally, it has been demonstrated that the contribution of the surface tension variation caused by temperature increases in the micro region can be neglected. This work will lead to a better understanding of the axial heat transfer coefe cient and temperature distribution on grooved surfaces, and how these parameters affect the e lm thickness.

Liquid–vapor interface of water–methanol mixture. I. Computer simulation

Abstract: Results of molecular dynamics computer simulation are presented for liquid–vapor interface of water–methanol mixture of various compositions at room temperature. The composition dependence of calculated surface tension is typical of aqueous solutions of organic compounds. The outermost surface layer is saturated with methanol even at low bulk concentrations of methanol. The density profile of each component seems oscillatory at some compositions.

Interfacial Tension of (Methane + Nitrogen) + Water and (Carbon Dioxide + Nitrogen) + Water Systems

Abstract: Interfacial tension data of (CH4 + N2) + H2O and (CO2 + N2) + H2O systems were measured using a pendant-drop method. The temperature and pressure ranges were 298−373 K and 1−30 MPa, respectively. The effects of gas composition, temperature, and pressure on the interfacial tension of the systems studied have been investigated. The linear gradient theory (LGT) was used to calculate the interfacial tensions of these two systems. The results show good agreement between the calculated and experimental interfacial tension data for the (CH4 + N2) + H2O system. However, it was found that the LGT model with one adjustable parameter is inadequate to give accurate predictions for the CO2 + H2O system and thus is not suitable for the description of the (CO2 + N2) + H2O system.

Alkyl chain interaction at the surface of room temperature ionic liquids: systematic variation of alkyl chain length (R = C(1)-C(4), C(8)) in both cation and anion of [RMIM][R-OSO(3)] by sum frequency generation and surface tension.

Abstract: The gas-liquid interface of halide-free 1,3-dialkylimidazolium alkyl sulfates [RMIM][R-OSO(3)] with R chain length from C(1)-C(4) and C(8) has been studied systematically using the surface-specific sum frequency generation (SFG) vibrational spectroscopy and surface tension measurements. From the SFG spectra, vibrational modes from the methyl group of both cation and anion are observed for all ionic liquid samples considered in the present study. These results suggest the presence of both ions at the gas-liquid interface, which is further supported by surface tension measurements. Surface tension data show a decreasing trend as the alkyl chain in the imidazolium cation is varied from methyl to butyl chain, with a specific anion. A similar trend is observed when the alkyl chain of the anion is modified and the cation is fixed.