scholarly journals The behaviour of crystals and lenses of fats on the surface of water.—Part II. The effect of temperature on the equilibrium pressure

1925 ◽  
Vol 109 (750) ◽  
pp. 318-330 ◽  
Keyword(s):  
Surface Tension ◽  
Pure Water ◽  
Hydrocarbon Chain ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Equilibrium Pressure ◽  
Equilibrium Surface Tension ◽  
Rate Of Spread ◽  
Definite Interval ◽  
Increasing Temperature

In Part I a study was made of the rate of spread and unimolecular nature of films of fatty substances, containing a long hydrocarbon chain and a polar “head,” over a surface of pure water or of N/100 HC1. It was shown that after a definite interval of time, the surface became saturated with a unimolecular film in equilibrium with either a crystal or a lens of the substance in question, and that the time taken to attain equilibrium as well as the equilibrium surface tension was a function of the temperature. In the present paper the effect of increasing temperature on the two-dimensional equilibrium pressure is considered in detail.

Adsorption of C14EO8 at the interface between its aqueous solution drop and air saturated by different alkanes vapor

2017 ◽  
Vol 19 (3) ◽  
pp. 2193-2200 ◽  
Author(s):  
R. Miller ◽  
E. V. Aksenenko ◽  
V. I. Kovalchuk ◽  
V. B. Fainerman
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Pure Water ◽  
Dynamic Surface Tension ◽  
Dynamic Surface ◽  
Equilibrium Surface ◽  
Equilibrium Surface Tension

The dynamic and equilibrium surface tension for drops of aqueous C14EO8 solutions at the interface to pure air or pentane, hexane, heptane and toluene saturated air, and the dynamic surface tension of pure water at these interfaces are presented.

scholarly journals Dependence of surface tension of fruit puree on temperature exposure

2021 ◽  
Vol 22 (6) ◽  
pp. 907-917
Author(s):  
L. K. Patsyuk ◽  
V. V. Kondratenko ◽  
M V. Lukyanenko
Keyword(s):  
Surface Tension ◽  
Surface Tension Coefficient ◽  
Effect Of Temperature ◽  
Technological Processing ◽  
Temperature Exposure ◽  
Food Media ◽  
Increasing Temperature ◽  
Apple Puree ◽  
Fruit Purée ◽  
Apple Purée

When developing food products with new properties using innovative technologies, it is important to obtain data on the physicochemical, thermal-physical and structural-mechanical properties of the processed food media. So, one of the key components in the selection of the mode of collapsing ultrasonic cavitation is the surface tension of vegetable purees. The paper presents research data (2020) on the effect of temperature on the surface tension coefficient of fruit puree of different viscosity. The objects of research are cherry plum, pear and apple puree, combined in a row by viscosity. The surface tension coefficient was determined by the stalagmometric method, for which the puree was preliminarily centrifuged. The measurements were carried out at temperatures of 25 and 35 °С. It was found that, under equal conditions of centrifugation of puree, the proportion of supernatant in pear puree is noticeably higher – 77.37 % to the weight of puree in comparison with cherry plum puree (67.20 %) and apple puree (52.75 %). This fact can be explained by the presence of stony cells in the former which form an incompressible sediment, which allows a greater separation of the dispersed phase (sediment) and the dispersion medium (supernatant). It was found that the coefficient of surface tension of fruit purees, despite the slight difference, decreases with increasing temperature. Analysis of the steepness of the slope of the curve characterizing the effect of temperature on the surface tension coefficient showed that temperature stabilization during technological processing is more required for pear puree.

Effect of temperature and hydric conditions on blood pH in embryonic snapping turtles (Chelydra serpentina)

1990 ◽  
Vol 68 (1) ◽  
pp. 190-193 ◽  
Author(s):  
Geoffrey F. Birchard ◽  
Mary J. Packard ◽  
Gary C. Packard
Keyword(s):  
Partial Pressure ◽  
Water Potential ◽  
Pure Water ◽  
Effect Of Temperature ◽  
Chelydra Serpentina ◽  
Blood Samples ◽  
Ph Changes ◽  
Blood Ph ◽  
Snapping Turtles ◽  
Increasing Temperature

The effect of temperature on blood pH in embryonic snapping turtles (Chelydra serpentina) was examined to determine whether the blood pH changes in the same manner as the neutral pH of pure water. Eggs were incubated on moistened vermiculite (water potential of −150 or −950 kPa) at 26 or 27 °C. On day 59 of incubation, eggs were placed in individual containers and assigned to incubators set at temperatures between 18.5 and 30 °C. Blood samples were taken on day 60 of incubation. Blood pH of the embryos varied in a manner similar to that observed in adults of this species: blood pH declined with increasing temperature, with a slope of −0.021 pH/°C. The decrease of blood pH with increasing temperature may be accomplished passively, with blood CO2 partial pressure increasing as a result of greater metabolic production of CO2 while the diffusive excretion of this gas remains relatively constant. No effect of substrate water potential on blood pH was observed.

scholarly journals The kinetic theory of surface films. Part I.—The surfaces of solutions

1925 ◽  
Vol 109 (749) ◽  
pp. 57-77 ◽  
Keyword(s):  
Surface Tension ◽  
Phase Boundary ◽  
Pure Water ◽  
Molar Fraction ◽  
Single Layer ◽  
Hydrocarbon Chain ◽  
Homogeneous Layer ◽  
Cooh Group ◽  
Surface Films ◽  
Small Molecular Weight

A study of the catalytic properties of solid surfaces has led to a belief that the distance at which molecules cease to attract one another appreciably is of the same order of magnitude as the diameter of an atom, a distance much smaller than that imagined by Laplace. On the Laplacian view the transition between liquid and vapour at a phase-boundary is gradual, but on the newer theory the non-homogeneous layer separating the homogeneous phases is little, if at all, greater than the diameter of a molecule. The work of Langmuir (1) on the influence of small quantities of certain insoluble organic substances upon the surface tension of water supports the latter view. The substances which are found to act in this way are hydrocarbons in which has been substituted an “ active ” group, such as COOH or OH. These groups tend to make the substance soluble in water, but the substitution of only one of them in a hydrocarbon containing more than twelve carbon atoms in the molecule is insufficient to cause any appreciable solution. Langmuir suggests that molecules of, say, palmitic acid placed on water orientate themselves, so that the COOH group is in the liquid phase while the hydrocarbon chain is in the vapour phase, a condition which is only realizable if the phase boundary is relatively sharp. His well-known trough experiments (2) amply support this idea, and confirm the necessary corollary : that a water surface of a given area can only accommodate a limited number of orientated molecules. N. K. Adam (3), in repeating and extending Langmuir’s experiments with more refined apparatus, has shown that the least area occupied by these molecules is in excellent agreement with that to be expected from the recent X-ray determinations of Sir William Bragg. In the paper in which his work on insoluble films is described Langmuir also deals with the lowering of the surface tension of water by soluble substances (4), such as the fatty acids and alcohols of small molecular weight. He suggests that the excess concentration of solute, which an application of Gibbs’ adsorption equation shows to exist in the neighbourhood of the phase boundary, is present as a single layer of molecules, orientated partially or completely like those of insoluble substances. In support of this he quotes a paper by Milner (5), where it is shown that soluble substances which depress the surface tension of water appear to give a surface excess reaching a constant limiting value for large depressions. This conclusion is drawn from the fact that the relation σ 0 — σ = α + β log 10 N (i) is found to represent the behaviour of solutions of acetic acid for large values of σ 0 — σ. In this equation σ is the surface tension of the solution, while σ 0 is that of pure water ; N is the molar fraction of the solute, and α and β are constants.

Discussion on Grosenbaugh and Yeung: “Flow Structure Near the Bow of a Two-Dimensional Body”

1990 ◽  
Vol 34 (03) ◽  
pp. 206-206
Author(s):  
G. E. Gadd
Keyword(s):  
Surface Tension ◽  
Surface Film ◽  
Pure Water ◽  
Marangoni Effect ◽  
Surface Region ◽  
Surface Flow ◽  
Surface Films ◽  
Soap Bubble ◽  
Two Dimensional ◽  
Reduce Surface Tension

A note on surface tension effects on breaking bow waves - In their interesting recent paper [1], Grosenbaugh and Yeung show that the forward extent of a breaking bow wave in front of a two-dimensional body can be significantly affected by the addition of surfactants to reduce surface tension. However, although they note that contaminants such as dust can also affect the surface flow, they appear to be unaware of the possibility that dynamic effects on surface tension, particularly when surfactants are present, may play an important role, as discussed in reference [2]. As shown by Davies [3], surface films can damp eddies at a free surface of a turbulent liquid. The mechanism is due to the so-called Marangoni effect; that is, where a surface film is locally stretched, the surface contaminant concentration is momentarily reduced, leading to an increase in surface tension which tends to contract the local surface region again. This is why a soap bubble is so much more stable than one formed in pure water. Similarly, upwelling flows associated with turbulence at a water surface cause local stretching and contraction which will tend to be opposed by the presence of the surface contaminant.

scholarly journals Synthesis of Oligomeric Silicone Surfactant and its Interfacial Properties

2019 ◽  
Vol 9 (3) ◽  
pp. 497 ◽  
Author(s):  
Da Yin ◽  
Pingya Luo ◽  
Jie Zhang ◽  
Xuyang Yao ◽  
Ren Wang ◽  
...  
Keyword(s):  
Surface Tension ◽  
Mass Concentration ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Critical Surface ◽  
Critical Surface Tension ◽  
Silicone Surfactant ◽  
Equilibrium Surface Tension ◽  
Increasing Temperature ◽  
Solid Liquid

During the exploitation of low permeability gas-condensate reservoirs, the mud filtrate, acidizing liquid, and fracturing fluid invade the reservoir and condensate gas, severely reducing the permeability of the reservoirs due to increased capillary pressure and water wettability. For the current paper, an oligomeric silicone surfactant (OSSF) containing sulfonic acid groups was synthesized to improve the flowback of such fluids. The critical micelle mass concentration and critical surface tension were determined by equilibrium surface tension. The surface tension increased with the hot rolling temperature and decreased with the addition of NaCl, KCl, or CaCl2. When the concentration exceeded critical micelle mass concentration, a micelle was formed and its size increased with mass concentration. OSSF adsorption through solid–liquid surface changed the surface chemical composition of the cores and transferred the wettability of cores from water-wet to preferential gas-wet by decreasing the surface energy. At the same time, the increasing temperature led to a change in the adsorption isotherm of quartz sand from Langmuir type (L-type) to “double plateau” type (LS-type) in the OSSF solution. In addition, NaCl decreased the relative foam volume of OSSF while extending the half-life. OSSF decreased the initial foaming volume and stability of the induction period and accelerated sodium dodecyl benzene sulfonate (SDBS) formation.

Dynamic surface tension of xylem sap at the air-water interface

2021 ◽  
Author(s):  
Reddy Prasanna Duggireddy ◽  
Eran Raveh ◽  
Gilboa Arye
Keyword(s):  
Surface Tension ◽  
Surface Activity ◽  
Pure Water ◽  
Xylem Sap ◽  
Dynamic Surface Tension ◽  
Bulk Solution ◽  
Diffusion Control ◽  
Dynamic Surface ◽  
Equilibrium Surface Tension ◽  
Air Interface

<p>The surface tension (ST) of xylem sap at the water-air interface is a crucial phenomenon, influencing many physiological events such as air seeding and embolism, by which xylem vessels become air-filled and cease to function. Refilling of embolized, may relies on sap’s surface activity at the interface. It is commonly assumed that the ST of xylem sap is equal to the ST of pure water (72 mN/m). However, xylem sap is a complex solution and consists of surface-active molecules that may adsorb and accumulate at the water-air interface and thereby reduce the ST of water as a function of their aqueous concentration. However, when a new water-air interface is formed, equilibrium ST is not reached instantaneously. Specifically, amphiphilic molecules are kinetically adsorbed and undergo orientation at the interface following diffusion from the bulk solution. Dynamic ST of xylem sap and liquid-solid interactions, describing the surface phenomena of the xylem of vascular plants is currently not fully understood. This is mainly due to a lack of quantitative knowledge on the rate and extent of dynamic and equilibrium ST of sap. In this regard, the main objective of this study is to quantify the dynamic and equilibrium ST of xylem sap as a function of their aqueous concentration. We extracted xylem sap from lemon trees and measured ST as a function of time using the pendant drop technique. The dynamic ST data were analyzed using empirical and diffusion-control mathematical models which adequately described the exponential-like decay of the ST as a function of time. The results showed reduced ST of water in the xylem sap, indicating significant surface activity, reaching equilibrium ST values as low as 42 mN/m. The rate of ST decay was higher in high sap concentration and reduced in diluted one. The results of dynamic and equilibrium ST and the corresponding model will be presented and their implications for xylem hydraulic functioning will be discussed.</p><p> </p><p>Keywords: Dynamic surface tension, Equilibrium surface tension, Diffusion, Xylem sap.</p><p> </p>

Temperature Effect on the Two-Dimensional Phase Transition Kinetics of Adenine Adsorbed at the Hg Electrode/Aqueous Solution Interface

2003 ◽  
Vol 68 (8) ◽  
pp. 1407-1419 ◽  
Author(s):  
Claudio Fontanesi ◽  
Roberto Andreoli ◽  
Luca Benedetti ◽  
Roberto Giovanardi ◽  
Paolo Ferrarini
Keyword(s):  
Phase Transition ◽  
Aqueous Solution ◽  
Phase Change ◽  
Temperature Effect ◽  
Transition Rate ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Solution Interface ◽  
Phase Transition Kinetics ◽  
Kinetics Of

The kinetics of the liquid-like → solid-like 2D phase transition of adenine adsorbed at the Hg/aqueous solution interface is studied. Attention is focused on the effect of temperature on the rate of phase change; an increase in temperature is found to cause a decrease of transition rate.

scholarly journals A pH-Responsive Foam Formulated with PAA/Gemini 12-2-12 Complexes

2021 ◽  
Vol 5 (3) ◽  
pp. 37
Author(s):  
Hernán Martinelli ◽  
Claudia Domínguez ◽  
Marcos Fernández Leyes ◽  
Sergio Moya ◽  
Hernán Ritacco
Keyword(s):  
Surface Tension ◽  
Dynamic Surface Tension ◽  
Foam Formation ◽  
Ph Responsive ◽  
Dynamic Surface ◽  
X Ray ◽  
Equilibrium Surface Tension ◽  
Potential Applications ◽  
The Stability ◽  
Air Interfaces

In the search for responsive complexes with potential applications in the formulation of smart dispersed systems such as foams, we hypothesized that a pH-responsive system could be formulated with polyacrylic acid (PAA) mixed with a cationic surfactant, Gemini 12-2-12 (G12). We studied PAA-G12 complexes at liquid–air interfaces by equilibrium and dynamic surface tension, surface rheology, and X-ray reflectometry (XRR). We found that complexes adsorb at the interfaces synergistically, lowering the equilibrium surface tension at surfactant concentrations well below the critical micelle concentration (cmc) of the surfactant. We studied the stability of foams formulated with the complexes as a function of pH. The foams respond reversibly to pH changes: at pH 3.5, they are very stable; at pH > 6, the complexes do not form foams at all. The data presented here demonstrate that foam formation and its pH responsiveness are due to interfacial dynamics.

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