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.

Influence of Surfactants and Plant Species on Leaf Retention of Spray Solutions

Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 567-572 ◽  
Author(s):  
Hans De Ruiter ◽  
André J.M. Uffing ◽  
Esther Meinen ◽  
Albertus Prins
Keyword(s):  
Surface Tension ◽  
Winter Wheat ◽  
Plant Species ◽  
Dynamic Surface Tension ◽  
Dynamic Surface ◽  
Black Nightshade ◽  
Equilibrium Surface Tension ◽  
Spray Solution ◽  
Determining Factor ◽  
Cuticular Surface

Spray solutions containing a cationic or a nonionic surfactant were applied to six plant species at a broad range of concentrations. The species investigated were three weeds (black nightshade, chamomile, and quackgrass) and three crops (winter wheat, pea, and tomato). The microroughness of the leaf surface as revealed by scanning electron microscopy appeared to be a relevant retention-determining factor. Plant species with crystalline epicuticular waxes (winter wheat, pea, and quackgrass) retained much less spray solution than the other species, which are characterized by a smooth cuticular surface. The two surfactants enhanced retention on species with a reflective surface, whereas retention on black nightshade, chamomile, and tomato was hardly influenced by addition of surfactants. The two surfactants had a similar influence on the retention. Surfactant at 1% (wt/v) enhanced retention on pea, winter wheat, and quackgrass by factors of twenty, six, and four, respectively, compared with retention without surfactant. A linear relation between retention and logarithm of surfactant concentration was observed. Retention of spray drops was related not to equilibrium surface tension of the spray solution but rather to dynamic surface tension.

scholarly journals Equilibrium Surface Tension, Dynamic Surface Tension, and Micellization Properties of Lactobionamide-Type Sugar-Based Gemini Surfactants

2013 ◽  
Vol 62 (6) ◽  
pp. 353-362 ◽  
Author(s):  
Tomokazu Yoshimura ◽  
Shin Umezawa ◽  
Akihiko Fujino ◽  
Kanjiro Torigoe ◽  
Kenichi Sakai ◽  
...  
Keyword(s):  
Surface Tension ◽  
Gemini Surfactants ◽  
Dynamic Surface Tension ◽  
Dynamic Surface ◽  
Equilibrium Surface ◽  
Equilibrium Surface Tension

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.

Effects of Dynamic Surface Tension and Gas Permeation Resistance on the Stability of Microbubbles

2007 ◽  
Author(s):  
Hiroyuki Takahira ◽  
Daishi Ito ◽  
Tomoaki Katsuyama
Keyword(s):  
Surface Tension ◽  
Ccd Camera ◽  
Dynamic Surface Tension ◽  
Gas Diffusion ◽  
Bubble Surface ◽  
Gas Permeation ◽  
Experimental Results ◽  
The Other ◽  
Dynamic Surface ◽  
The Stability

To understand the stability of microbubbles, the shrinkage and growth of microbubbles under variation of a pressure field are observed with a CCD camera. The influence of gas diffusion is investigated for two kinds of microbubbles; one is Levovist which is an air microbubble coated by palmitic acid, and the other is Imavist which is a PFC gas microbubble covered by lipid and surfactant. It is shown that when the ambient liquid pressure increases, a tiny microbubble shrinks accompanied with surface depression, and does not return to the initial size even after the pressure is reduced. On the other hand, a large microbubble shrinks nearly spherically. The depression of bubble surface suggests the formation of multilayers of surfactant or lipid on bubble surface. It is also shown that air diffusion enhances the growth of the Imavist. A bubble model is also constructed by considering dynamic surface tension and gas permeation resistance of surfactant or lipid layers. The previous experimental results in which a microbubble was trapped with a laser trapping technique are compared with simulations based on the model. The results show that the rate of adsorption of surfactant is much faster than the shrinking speed of microbubbles. The decrease of surface tension due to the decrease of the surface area of a microbubble is a significant factor to determine the bubble profile. Also, the present experimental results are compared with simulations. The simulations considering the gas permeation resistance are in good agreement with the experiments for nearly spherical bubbles. The results also show that the increase of the permeation resistance during bubble shrinkage stabilizes microbubbles.

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>

Effect of Oxyethylene Groups of Fatty Alcohol Polyoxyethylene Ether Sodium Sulfates on Equilibrium and Dynamic Surface Tension in Relation to Wetting Properties

2021 ◽  
Vol 58 (5) ◽  
pp. 394-400
Author(s):  
Xiaodan Ren ◽  
Ping Li ◽  
Jianbo Li ◽  
Xiaoyi Yang ◽  
Chaohua Guo ◽  
...  
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Fatty Alcohol ◽  
Dynamic Surface Tension ◽  
Dynamic Surface ◽  
Polyoxyethylene Ether ◽  
Wetting Properties ◽  
Equilibrium Surface Tension ◽  
Fatty Alcohol Polyoxyethylene Ether ◽  
Air Liquid Interface

Abstract The effect of hydrophilic chain of surfactants fatty alcohol polyoxyethylene ether sodium sulphates (AEnS, n = 2, 3, 7) on surface properties and wetting properties was investigated by the measurement of equilibrium surface tension, dynamic surface tension and dynamic contact angle. The fatty alcohol polyoxyethylene ether sodium sulphates with different head group sizes were used. From the results of equilibrium surface tension measurements, we could obtain the critical micellisation concentration, adsorption efficiency, maximum surface excess concentration and Langmuir equilibrium adsorption constant at air/liquid interface. The dynamic surface tension results showed that the adsorption of aqueous solutions at the air/liquid interface follows a mixed-diffusion kinetic adsorption mechanism. In conclusion, for both studied surfactant, the longer the oxyethylene chains, the higher the maximum rate of surface tension reduction, the higher the diffusivity and wetting properties in terms of contact angle.

scholarly journals The unusual symmetric reopening effect induced by pulmonary surfactant

2014 ◽  
Vol 116 (6) ◽  
pp. 635-644 ◽  
Author(s):  
Eiichiro Yamaguchi ◽  
Matthew J. Giannetti ◽  
Matthew J. Van Houten ◽  
Omid Forouzan ◽  
Sergey S. Shevkoplyas ◽  
...  
Keyword(s):  
Surface Tension ◽  
Pulmonary Surfactant ◽  
Sodium Dodecyl ◽  
Dynamic Surface Tension ◽  
Dynamic Surface ◽  
Airway Reopening ◽  
Image Velocimetry ◽  
Microparticle Image Velocimetry ◽  
The Stability ◽  
Do So

This study investigates the stability of a finger of air as it propagates into a liquid-filled model of a liquid-filled model of a pulmonary bifurcation. We seek to elucidate the stability characteristics of the reopening of daughter airways, an event that may be important to the treatment of acute lung disease. To do so, we investigated the symmetry of reopening under conditions of nearly constant surface tension with 1) purified H2O or 2) an anionic surfactant (sodium dodecyl sulfate). Dynamic surface tension was investigated using pulmonary surfactant (Infasurf) with and without the presence of albumin. Flow visualization was accomplished using a microparticle image velocimetry (μ-PIV)/shadowgraph system through which we measured 1) the propagation velocity of the finger of air that reopens each daughter branch, and 2) the instantaneous and averaged velocity field of liquid phase surrounding the tip of the propagating bubble. Only pulmonary surfactant demonstrated the ability of maintaining a nearly symmetric propagation in the daughter channels, which is likely to lead to homogeneous airway reopening. In contrast, when pulmonary surfactant was inactivated by albumin or when the system was held at a nearly constant surface tension, reopening occurred asymmetrically. Our analysis suggests that Infasurf's dynamic surface tension qualities are important to stabilize the removal of liquid obstructions. This demonstrates a new important function of pulmonary surfactant for airway reopening of a multibranched network.

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