Showing papers on "Surface tension published in 1971"
TL;DR: In this article, the breakdown of anodic oxide films is described thermodynamically as a mechanical deformation or crack formation, and the breakdown potential at which the film thickness is critical depends on the anion concentration in solution.
366 citations
TL;DR: This paper showed that the hydration of ions and the wetting of the surface of an electrolyte crystal are very similar phenomena that can be described by the same interfacial tension, which supports the theory that ion hydration and surface wetting are similar phenomena.
364 citations
TL;DR: It is suggested that the primary role of the conjunctival glycoproteins in the eye is to transform the low-energy corneal surface into a higher energy surface via adsorption.
201 citations
TL;DR: In this paper, the interfacial tension between the two aqueous phases of dextran water systems was determined by the rotating drop method, and a linear relationship between the logarithm of the inter-phase tension and the length of the tie line of the phase diagram was found.
133 citations
TL;DR: In this article, the surface tension of surfactant solutions can be observed conveniently as a function of time in the 1- to 100-sec range with some modifications of the normal maximum bubble pressure method.
128 citations
119 citations
TL;DR: In this article, the Barker-Henderson perturbation theory for uniform fluids is extended to include nonuniform fluids and the surface tension for a Lennard-Jones fluid is calculated by minimizing the free energy in the surface layer.
Abstract: The Barker—Henderson perturbation theory for uniform fluids is extended to include nonuniform fluids. The surface tension for a Lennard‐Jones fluid is calculated by minimizing the free energy in the surface layer. Comparison with the corresponding experimentally obtained values of surface tension for argon shows that excellent agreement is obtained in the case of a Lennard‐Jones 12–6 fluid with values of the potential parameters determined from the second virial coefficient.
117 citations
TL;DR: The climbing of Marangoni films up vertical solid surfaces was investigated experimentally and theoretically as discussed by the authors, and the results confirmed the hypothesis that previously observed liquid films formed against gravitational forces above equilibrium menisci are produced by surface-tension inequalities.
Abstract: The climbing of Marangoni films up vertical solid surfaces was investigated experimentally and theoretically. The system considered was a nonisothermal plate with its warm end partially immersed in a nonvolatile liquid. Observed film thicknesses and rates of climb were in agreement with an approximate hydrodynamic model obtained by assuming the supply capacity of the film to be rate limiting.
The results of this study confirm the hypothesis is that previously observed liquid films formed against gravitational forces above equilibrium menisci are produced by surface-tension inequalities. It is pointed out that hydrodynamic processes cannot allow for the advancement of the leading edge of Marangoni films and a separate physicochemical process is required to explain spontaneous spreading of these films. Evidence is presented for the formation of much thinner primary films ahead of the secondary bulk films described by hydrodynamics. These primary films appear to be produced by a combination of multilayer adsorption and/or surface diffusion. The kinetics of these diffusional processes may limit spreading rates when surface-tension gradients become sufficiently large.
Finally, the Marangoni films were found to be unstable in a manner hithertonot considered.
110 citations
01 Mar 1971
TL;DR: In this article, a novel experimental technique for the measurement of surface tension of molten metals has been developed based on the Rayleigh equation which relates frequency and surface tension for an oscillating drop.
Abstract: A novel experimental technique for the measurement of surface tension of molten metals has been developed. It is based on the Rayleigh equation which relates frequency and surface tension for an oscillating drop. A systematic study has shown this equation to be valid for a liquid metal droplet levitated electromagnetically in an inert flowing gas with no prior calibration required. It is, therefore, an absolute method. The frequencies of oscillation of droplets of pure iron and nickel in a 6 pct H2-He gas mixture were measured by high speed cinematography. Surface tensions were obtained for temperatures of 1550° to 1780°C for iron and 1475° to 1650°C for nickel.
87 citations
TL;DR: In this paper, a large number of collisions between two water drops, one of cloud droplet size (70 μ diameter) and one of raindrop size (1.0-3.5 mm diameter) reveal the conditions under which a collision may result in coalescence, bouncing, or partial coalescence.
Abstract: Photographic and visual observations of a large number (> 104) of collisions between two water drops, one of cloud droplet size (70 μ diameter) and one of raindrop size (1.0–3.5 mm diameter) reveal the conditions under which a collision may result in coalescence, bouncing, or partial coalescence. Coalescence occurs for 85–95% of collisions at velocities equivalent to the difference in terminal velocities of the drop-droplet pair. Bouncing always results from collisions in which the droplet center trajectory does not intersect the collector drop surface. Partial coalescence occurs infrequently and is restricted to narrow ranges of velocities and incident angles.
Barriers to coalescence are the existence of an air film between the approaching surfaces and the ability of the drop surface to deform on collision. Sufficient electrical attraction, long contact time, or high impact velocity can overcome these barriers and insure coalescence.
Surface tension variations of ±15% from the value for distilled water did not affect the coalescence process at velocities equivalent to natural conditions. Electric charges of like or unlike sign on the drop pair are found to enhance coalescence once a threshold charge of 10−2 esu on the collector drop is attained (with a droplet charge of −10−5 esu); higher drop charges insure 100% coalescence.
Values of coalescence efficiency E2 calculated from experiments, lead to an expression E2 = R2/(R + r)2, which is valid at least for drop radii 400 μ
87 citations
TL;DR: In this article, the boundary conditions on the pressure and pressure gradient for use with Reynolds' equation were developed as functions of a dimensionless parameter involving viscosity, speed, and surface tension.
Abstract: The pressure and flow conditions upstream of the rupture point of a lubricating film are analyzed with the theoretical model derived in Part I. The boundary conditions on the pressure and pressure gradient for use with Reynolds’ equation are developed as functions of a dimensionless parameter involving viscosity, speed, and surface tension. The load-carrying capacity which results from the use of these new boundary conditions does not differ appreciably from that of other boundary conditions in current use, except when the bearing load is extremely light, or when surface tension is large compared with the product of speed and viscosity. A simple experiment was conducted using a cylindrical lens bearing on a rotating oil-lubricated glass plate. Measurements of the bearing load and the location of the film attachment to the lens were in good agreement with the theory.
01 Dec 1971
TL;DR: The surface free energy and polarity values of a number of organic pigments were obtained from contact angle measurements and the interfacial tension equation of Wu(1) as mentioned in this paper, and the pigment types studied are phthalocyanine, quinacridone, toluidine red, isoindolinone, indanthrone, β-oxynaphthoic acid derivative, and thioindigoid red.
Abstract: The surface free energy and polarity values of a number of organic pigments are obtained from contact angle measurements and the interfacial tension equation of Wu(1). The pigment types studied are phthalocyanine, quinacridone, toluidine red, isoindolinone, indanthrone, β-oxynaphthoic acid derivative, and thioindigoid red. The surface free energies obtained agree reasonably well with those predicted from parachor and density values.
TL;DR: A pure phosphatidyl choline containing branched-chain, saturated acyl substituents has been prepared by a novel synthesis and membranes formed from this non-autoxidizable, pure phospholipid are very stable and have an interfacial tension of 1.5 ± 0.1 dyne/cm at 24°.
TL;DR: In this article, a new technique was developed for measuring the differential interfacial tension as a function of potential at solid-solution interfaces, which utilizes the bending experienced by a thin electrode, insulated on one side, when the interfacial tensor tension is changed.
TL;DR: In this paper, analytical solutions for the transfer of an adsorbing solute across a liquid-liquid interface taking into account the effects of molecular diffusion in both bulk phases, adsorptive accumulation at the interface, and energy barriers to adsorption and/or desorption were obtained.
Abstract: Analytical solutions are obtained for the transfer of an adsorbing solute across a liquid-liquid interface taking into account the effects of molecular diffusion in both bulk phases, adsorptive accumulation at the interface, and energy barriers to adsorption and/or desorption. These solutions show that while adsorptive accumulation alone affects the transfer rate but little, the presence of an adsorption or desorption barrier can significantly affect the bulk concentration profiles and decrease the mass transfer rate. The presence of a desorption barrier is shown to cause the dynamic interfacial tension to pass through a minimum below the steady state value. For some systems it is conceivable that the interfacial tension minimum would be sufficiently low that a slight agitation would result in spontaneous emulsification.
Dynamic interfacial tension data for oil-water systems with interface ages from 0.05 to 1.5 sec. are obtained using a laminar contracting liquid jet. The data indicate the presence of a small net desorption barrier to the transfer of normal and isobutyric acids from oil to water and large barriers to both the adsorption and desorption of 1,5 pentanediol.
01 Feb 1971
TL;DR: In this paper, the sessile drop technique has been used to determine the surface tension of pure silver and gold alloys, and the results were in good agreement with previous data reported in the literature.
Abstract: The sessile drop technique has been used to determine the surface tension of silver-gold alloys. The techniques of data reduction are discussed and an improved one is presented. The measurements are in good agreement with previous data reported in the literature for pure silver and gold. The surface tension of alloys at 1108‡C was found to behave according to the prediction of the perfect solution model.
01 Sep 1971
TL;DR: In this article, the boundary-value problem for the velocity potential of a wave-maker is solved for both infinite and finite constant depth, and the solution of the corresponding problem concerning the axisymmetric wave motion due to a vertical cylindrical wavemaker is deduced in conclusion.
Abstract: The classical wave-maker problem to determine the forced two-dimensional wave motion with outgoing surface waves at infinity generated by a harmonically oscillating vertical plane wave-maker immersed in water was solved long ago by Sir Thomas Havelock. In this paper we reinvestigate the problem, making allowance for the presence of surface tension which was excluded before, and obtain a solution of the boundary-value problem for the velocity potential which is made unique by prescribing the free surface slope at the wave-maker. The cases of both infinite and finite constant depth are treated, and it is essential to employ a method which is new to this problem since the theory of Havelock cannot be extended in the latter case of finite depth. The solution of the corresponding problem concerning the axisymmetric wave motion due to a vertical cylindrical wave-maker is deduced in conclusion.
TL;DR: The contact angles of several liquids on human skin were measured before and after extraction of surface lipids with acetone to determine the critical surface tension of the skin by extrapolating the cosines of the contact angle of the liquids as a function of their surface tensions to unity.
TL;DR: In this article, it is shown that consideration of the condition of single molecules in the surface can provide an explanation of the tendency of liquid surfaces to contract, but that in order to understand the origin of the tensile tangential stress, it is necessary to examine the variation of averaged quantities, namely pressure and density.
Abstract: It is shown that consideration of the condition of single molecules in the surface can provide an explanation of the tendency of liquid surfaces to contract, but that in order to understand the origin of the tensile tangential stress in the surface it is necessary to examine the variation of averaged quantities, namely pressure and density.
TL;DR: In this paper, a ternary liquid system methanol-water-tribromomethane was made by rapid mixing of stable solutions, and the induction times for the appearance of turbidity were measured at 25 °C.
01 Nov 1971-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: The surface tension of Pb−Sn alloys are not straight-line functions of temperature and the evidence indicates that the temperature coefficients of surface tension are slightly positive at the liquidus temperature.
Abstract: The surface tensions of 99.9999 pct Pb and Sn and of alloys made from lead and tin of the same purity have been measured by the sessile-drop method. The surface tension of lead was determined from the melting point, the surface tension of tin from 200°C (32°C of supercooling) and the surface tensions of the Pb−Sn alloys from the respective liquidus temperatures, all, up to a temperature of about 560°C. Within the limits of experimental error, data for both pure metals plot in a rectilinear fashion with negative slopes, thus: γlead=472.7−0.085t(±5) dyne/cm γtin=569.0−0.080t((±5) dyne/cm The surface tensions of Pb−Sn alloys are not straight-line functions of temperature and the evidence indicates that the temperature coefficients of surface tension are slightly positive at the liquidus temperature.
TL;DR: In this article, a photographic technique was used to determine mass transfer rates from single drops and the reduction due to the surface active material was evaluated, based on the interpretation of measurements in terms of an active and inactive surface region.
TL;DR: In this paper, a coordinate cathetometer was used to measure the dynamic surface tension of an elliptical diaphragm orifice made of 2 mil Mylar film and the orifice was made nonwetting by carefully coating it with paraffin.
TL;DR: In this paper, the surface tension of pure glycols at different temperatures and the volume contraction in an aqueous solution and volume fraction in the surface phase of an annealing solution were studied.
Abstract: The surface tensions of aqueous solutions of 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, and 1,4-butanediol were measured at 20, 30, and 40°C. The correlation between the surface tension of pure glycols at different temperatures and the volume contraction in an aqueous solution and volume fraction in surface phase of an aqueous solution are studied.
TL;DR: In this paper, the authors considered the mechanism controlling rapid aging of surfaces of aqueous solutions with reference to the variation of dynamic surface tension with time and proposed a new surface model which reduces to the Sutherland result as a special case.
TL;DR: In this article, an X-radiographic technique was developed to obtain profiles of molten ceramic menisci and pendant drops sealed in molybdenum or tungsten capsules.
Abstract: An X-radiographic technique was developed to obtain profiles of molten ceramic menisci and pendant drops sealed in molybdenum or tungsten capsules. The surface tension for Al2O3 was calculated from the shape of the drops or menisci. Molybdenum capsules lowered the surface tension value. The density was 3.01 g/cm8 at the melting point.
01 Nov 1971-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, the surface tension of liquid Ag-O alloys has been determined by the sessile drop method and the surface activity of oxygen is estimated to be of the order of 30 kcal per mole.
Abstract: The surface tensions of liquid Ag-O alloys have been determined by the sessile drop method. The surface activity of oxygen, as measured by −(dσ/dX
O)XO→0j, where σ is the surface tension of the metal andX
O the mole fraction of oxygen, is quite large and equals 3.80×105 dyne per cm at 980°C and 1.35×105 dyne per cm at 1108°C. The heat of adsorption of oxygen is estimated to be of the order of 30 kcal per mole. Application of the monolayer approximation shows that liquid silver becomes saturated with oxygen when each adsorbed oxygen atom occupies an area of 33±5A2. Small additions of platinum to silver do not change the characteristics of the adsorption of oxygen appreciably. An analysis of the data is consistent with the conclusion that saturation of the surface of liquid silver with oxygen results from the formation of an ionic two-dimensional compound at the surface. This hypothesis is tested in the case of several other systems and yields satisfactory results. The structure of these compounds is discussed. In the case of the Ag-O system, it appears to correspond to the stoichiometry Ag3O.