scholarly journals Deformation near a liquid contact line on an elastic substrate

2014 ◽  
Vol 470 (2167) ◽  
pp. 20140085 ◽  
Author(s):  
Chung-Yuen Hui ◽  
Anand Jagota
Keyword(s):  
Surface Tension ◽  
Energy Balance ◽  
Contact Line ◽  
Liquid Drop ◽  
Equilibrium Configuration ◽  
Force Balance ◽  
Surface Tensions ◽  
Elastic Substrate ◽  
Configurational Energy ◽  
Young's Equation

The equilibrium configuration of a liquid drop on a solid is determined by local energy balance. For a very stiff substrate, energy balance is represented by Young's equation. The equilibrium configuration near a line separating three fluids, in contrast, is determined by a balance of forces—their surface tensions—which is represented graphically by Neumann's triangle. We argue that these two are limiting cases of the more general situation of a drop on an elastic substrate in which both configurational energy balance and force balance must be satisfied independently. By analysing deformation close to the contact line of a liquid drop on an elastic substrate, we show that the transition from the surface tension-dominated regime to the elasticity-dominated regime is controlled by a dimensionless parameter: the ratio of an elasto-capillary length to the characteristic length scale over which surface tension acts. Because of the influence of substrate elasticity, the contact angle is not necessarily given by Young's equation. For compliant solids, we show that the local deformation and stress fields near the contact line are governed by surface tensions. However, if surface tension happens to be different from surface energy, configurational energy balance may not be consistent with force balance.

Measurement of Burst Pressure of Capillary Burst Valve

2010 ◽  
Author(s):  
Hong Chen ◽  
Toru Yamada ◽  
Mohammad Faghri
Keyword(s):  
Surface Tension ◽  
Solid Surface ◽  
Burst Pressure ◽  
Surface Tensions ◽  
Fluid Surface ◽  
Mechanical Components

Capillary burst valve (CBV), a counterpart to an elastomeric diaphragm microvalve, handles fluid in microchannels by capillarity. Thus, it avoids integration of mechanical components. We experimentally estimated the burst pressure, beyond which CBV cannot hold fluid, using fluids with distinct surface tensions in CBVs grafted with distinct surface constitutions in microchannels. We found that both the fluid surface tension and the solid surface constitution influence the burst pressure. The burst pressure reduces more significantly under the influence of the fluid surface tension.

scholarly journals Sorting Liquid Droplets by Surface Tension Using Devices with Quasi-Superamphiphobic Coatings

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 820 ◽  
Author(s):  
Yu-Ping Zhang ◽  
Di Fan ◽  
Xiu-Zhi Bai ◽  
Cheng-Xing Cui ◽  
Jun Chen ◽  
...  
Keyword(s):  
Surface Tension ◽  
Surface Energy ◽  
Solid Surface ◽  
Glass Slide ◽  
Liquid Droplets ◽  
Surface Tensions ◽  
Coated Nanoparticles ◽  
Tilting Angle ◽  
Time Distance ◽  
Alcoholic Strength

Any solid surface with homogenous or varying surface energy can spontaneously show variable wettability to liquid droplets with different or identical surface tensions. Here, we studied a glass slide sprayed with a quasi-superamphiphobic coating consisting of a hexane suspension of perfluorosilane-coated nanoparticles. Four areas on the glass slide with a total length of 7.5 cm were precisely tuned via ultraviolet (UV) irradiation, and droplets with surface tensions of 72.1–33.9 mN m−1 were categorized at a tilting angle of 3°. Then, we fabricated a U-shaped device sprayed with the same coating and used it to sort the droplets more finely by rolling them in the guide groove of the device to measure their total rolling time and distance. We found a correlation between ethanol content/surface tension and rolling time/distance, so we used the same device to estimate the alcoholic strength of Chinese liquors and to predict the surface tension of ethanol aqueous solutions.

Preparation and Properties of Amide Surfactants

2012 ◽  
Vol 550-553 ◽  
pp. 99-102
Author(s):  
Bao Cai Xu ◽  
Gui Ju Zhang ◽  
Yun Xia Li ◽  
Lu Cui
Keyword(s):  
Surface Tension ◽  
Critical Micelle Concentration ◽  
Aqueous Solutions ◽  
Surface Activity ◽  
Surface Tensions ◽  
Equilibrium Surface ◽  
Minimum Surface Tension ◽  
Dilute Aqueous Solutions ◽  
Lipophilic Groups ◽  
Long Chain

Amide surfactants have modified structures with lipophilic groups connecting hydrophilic groups through amido bond. The preparation of three families of amide surfactants including long chain N-acyl sarcosinates, amidopropyl dimethyl hydroxypropyl sulfobetaines and lauryl amidopropyl trimethyl ammoniums were discussed. The study of the surface activity of these compounds by measuring the equilibrium surface tensions of their dilute aqueous solutions were described. The minimum surface tension and the critical micelle concentration values of these compounds are given.

Inward Flow of Micro-Particles in an Evaporating Di-Dispersed Colloid Droplet on Hydrophilic Surface

2009 ◽  
Author(s):  
Jung-Yeul Jung ◽  
Young Won Kim ◽  
Jung Yul Yoo
Keyword(s):  
Surface Tension ◽  
Contact Line ◽  
Surface Tension Force ◽  
Nano Particles ◽  
Tension Force ◽  
Hydrophilic Surface ◽  
Micro Particles

It is well known that the liquid and the nanoparticles in an evaporating colloid droplet on the hydrophilic surface move radially outward for the contact line to maintain its position. However, the motion of micro-/nano-particles in an evaporating di-dispersed colloid droplet has not been reported to date. In this study, an experiment on an evaporating di-dispersed colloid droplet on the hydrophilic surface is carried out. It is found that nano-particles move radially outward and remain at the contact line while micro-particles move inward toward the center of the droplet. Further the mechanism of the micro-particles moving toward the center of the droplet is found to be due to the surface tension force of the liquid.

Dynamic surface tension of xylem sap lipids

2020 ◽  
Vol 40 (4) ◽  
pp. 433-444 ◽  
Author(s):  
Jinlong Yang ◽  
Joseph M Michaud ◽  
Steven Jansen ◽  
H Jochen Schenk ◽  
Yi Y Zuo
Keyword(s):  
Surface Tension ◽  
Surface Area ◽  
Xylem Sap ◽  
Dynamic Surface Tension ◽  
Liquid Interfaces ◽  
Surface Tensions ◽  
Local Surface ◽  
Dynamic Surface ◽  
Equilibrium Surface ◽  
Pit Membrane

Abstract The surface tension of xylem sap has been traditionally assumed to be close to that of the pure water because decreasing surface tension is thought to increase vulnerability to air seeding and embolism. However, xylem sap contains insoluble lipid-based surfactants, which also coat vessel and pit membrane surfaces, where gas bubbles can enter xylem under negative pressure in the process known as air seeding. Because of the insolubility of amphiphilic lipids, the surface tension influencing air seeding in pit pores is not the equilibrium surface tension of extracted bulk sap but the local surface tension at gas–liquid interfaces, which depends dynamically on the local concentration of lipids per surface area. To estimate the dynamic surface tension in lipid layers that line surfaces in the xylem apoplast, we studied the time-dependent and surface area-regulated surface tensions of apoplastic lipids extracted from xylem sap of four woody angiosperm plants using constrained drop surfactometry. Xylem lipids were found to demonstrate potent surface activity, with surface tensions reaching an equilibrium at ~25 mN m-1 and varying between a minimum of 19 mN m-1 and a maximum of 68 mN m-1 when changing the surface area between 50 and 160% around the equilibrium surface area. It is concluded that xylem lipid films in natural conditions most likely range from nonequilibrium metastable conditions of a supersaturated compression state to an undersaturated expansion state, depending on the local surface areas of gas–liquid interfaces. Together with findings that maximum pore constrictions in angiosperm pit membranes are much smaller than previously assumed, low dynamic surface tension in xylem turns out to be entirely compatible with the cohesion–tension and air-seeding theories, as well as with the existence of lipid-coated nanobubbles in xylem sap, and with the range of vulnerabilities to embolism observed in plants.

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