Sessile-Water-Droplet Contact Angle Dependence on Adsorption at the Solid−Liquid Interface

2010 ◽  
Vol 114 (11) ◽  
pp. 5088-5100 ◽  
Author(s):  
H. Ghasemi ◽  
C. A. Ward
Author(s):  
C. A. Ward

A method for determining the surface tension of solid-fluid interfaces has been proposed. For a given temperature and fluid-solid combination, these surface tensions are expressed in terms of material properties that can be determined by measuring the amount of vapor adsorbed on the solid surface as a function of xV, the ratio of the vapor-phase pressure to the saturation-vapor pressure. The thermodynamic concept of pressure is shown to be in conflict with that of continuum mechanics, but is supported experimentally. This approach leads to the prediction that the contact angle, θ, can only exist in a narrow pressure range and that in this pressure range, the solid-vapor surface tension is constant and equal to the surface tension of the liquid-vapor interface, γLV. The surface tension of the solid-liquid interface, γSL, may be expressed in terms of measurable properties, γLV and θ: γSL = γLV(1 − cosθ). The value of θ is predicted to depend on both the pressure in the liquid at the three-phase, line x3L, and the three-phase line curvature, Ccl. We examine these predictions using sessile water droplets on a polished Cu surface, maintained in a closed, constant volume, isothermal container. The value of θ is found to depend on the adsorption at the solid-liquid interface, nSL = nSL(x3L,Ccl). The predicted value of θ is compared with that measured, and found to be in close agreement, but no effect of line tension is found.


2009 ◽  
Vol 256 (1) ◽  
pp. 274-279 ◽  
Author(s):  
Kamil Wojciechowski ◽  
Anna Brzozowska ◽  
Sebastien Cap ◽  
Witold Rzodkiewicz ◽  
Thomas Gutberlet

Langmuir ◽  
2015 ◽  
Vol 31 (3) ◽  
pp. 982-986 ◽  
Author(s):  
Takashi Nishiyama ◽  
Yutaka Yamada ◽  
Tatsuya Ikuta ◽  
Koji Takahashi ◽  
Yasuyuki Takata

1970 ◽  
Vol 48 (5) ◽  
pp. 865-866 ◽  
Author(s):  
A. C. Lowe ◽  
A. C. Riddiford

Studies of the advancing contact angle of water upon several alkylchlorosilaned glass surfaces at 22 °C lead to the view that, at zero or very low interfacial velocities, the free energy per unit area of the solid/liquid interface is governed by both dispersive and polar forces. At higher velocities, the polar forces may be neglected.


2006 ◽  
Vol 21 (12) ◽  
pp. 3222-3233 ◽  
Author(s):  
Laurent Gremillard ◽  
Eduardo Saiz ◽  
Velimir R. Radmilovic ◽  
Antoni P. Tomsia

The wetting of Sn3Ag-based alloys on Al2O3 has been studied using the sessile-drop configuration. Small additions of Ti decrease the contact angle of Sn3Ag alloys on alumina from 115° to 23°. Adsorption of Ti-species at the solid–liquid interface prior to reaction is the driving force for the observed decrease in contact angle, and the spreading kinetics is controlled by the kinetics of Ti dissolution into the molten alloy. The addition of Ti increases the transport rates at the solid–liquid interface, resulting in the formation of triple-line ridges that pin the liquid front and promote a wide variability in the final contact angles.


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