Contact angle, liquid/surface

S = length of side of corrugation = equivalent diameter, m SE = factor to account for surface texturing 9 = corrugation angle, measured from the horizontal, deg Y = contact angle, liquid/surface, deg, estimated from cos y = 5.211 o = surface tension, mN/m... 

PEI, Stearate, Infra-Red laser treatment. Diffusion, ATR-FTIR, Contact Angle, Liquid-Surface Affinity... 

A simple —but incorrect — relationship between the height of capillary rise, capillary radius, contact angle, and surface tension is easily derived. At equilibrium the vertical component of the surface tension (2icRcy cos 0) equals the weight of the liquid column, approximated as the weight of a cylinder of height h and radius Rc. This leads to the approximation... 

From the Young contact angle the surface tension is assessed, using Eq. (1) and a correlation for interfacial tensions, such as given by Eq. (2) some correlations require repetition of the process with a few different liquids in order to be able to assess the surface tension. 

Contact angle measurements provide information on the wettability of the sample, the surface energetics of the solid, and the interfacial properties of the solid-liquid interface. The samples were immersed in water and captive air and octane bubbles were determined by measuring the bubble dimensions. By measurement of both air and octane contact angles the surface free energy (.y) of the solid-vapor ( > ) interface may be calculated by use of Young s equation and the narmonic mean hypothesis for separation of the dispersive and polar components of the work of adhesion. This method for determination of surface and interfacial proper-... 

Some consequences of such structural deviations are that in narrow pores the contact angle and surface tension may differ from their macroscopic values. Also the liquid-vapour phase behaviour differs from that in bulk. Here we shall... 

The Kelvin equation takes into account molecule/solid and intermolecular interactions using contact angle and surface tension, respectively. However, the Kelvin approach is not appropriate for de.scription of adsorption on small mesopores. Saam and Cole developed the thermodynamic theory with the average molecular potential for liquid helium in a cylindrical pore in order to understand unusual properties of liquid helium[19,20]. Findenegg et al have applied the Saam-Cole theory to elucidate fluid phenomena near the critical temperature[21]. The Saam-Cole theory includes the molecule/solid interaction in a form of the sum of the dispersion pair interactions. The Saam-Cole theory is fit for description of adsorption phenomena in regular mesopores[22j. 

For the case of a static liquid bridge of contact angle 0, surface tension induces an attractive capillary force Fcap between the two particles... 

The mean pore size of a liquid membrane support determines the force which holds the liquid membrane within the pore structure. The Young-Laplace equation (28) relates the force holding a liquid within a cylindrical capillary to the contact angle, the surface tension, and the radius of the pore ... 

At a first approach we can take the feasibility of desorption as the distinguishing difference between physically adsorbed and chemisorbed films. Even though this criterion may break down both experimentally and semantically in certain cases, it is workable as an initial guideline and it keeps us from becoming enmeshed in exceptions and modifications before we are ready for them. Chemisorbed films can be put on the adsorbing surfaces by the same techniques as physically adsorbed films retraction from the melt or from the liquid, retraction from solution, vapor deposition, etc. Chemisorbed films iHu respond to probes for the nature of the film—e.g. drop contact angle or surface potential — in the same way as physically adsorbed films. It is not until we attempt to desorb the film that we become aware of the difference between physical adsorption and chemisorption, as exemplified by the observations of Timmons and Zisman cited above [10]. 

Fluorocarbon and hydrocarbon modified PDMS surfaces are compared in Table 2. The contact angle data are obtained by the Good-Girifalco-Fowkes equation. It is striking that the hydrocarbon contact angle liquid gives better agreement with the JKR result for the hydrocarbon surface whereas the fluorocarbon liquid data better fit the fluorocarbon surface... 

This experiment uses the FTA200 table interface analyzer to measure the contact angle and surface tension between the liquid and solid. Surface analyzer survey liquid and solid, shows the interfacid tension. The standard deviation of the contact angle measurement is smaller than 1°. The standard deviation of surface tension measurement is smaller than 0.5 m N m . 

The suggestion that the wool fiber surface could be different in vacuum conditions compared to other environments (e.g., in a liquid) may be well founded. Horr [69] has recently studied contact angles and surface energy values previously determined for wool [71] as they related to the surface components that exist on wool such as methyl-, methylene-, keratin, and absorbed vapors. He has suggested that the outermost region on the wool surface cannot consist of methyl groups exclusively as had been indicated in Negri et al. s model [42]. 

Owing to the method of contact-angle or surface-energy measurement, the surface of wool necessarily includes the region between cuticle cells in addition to the cuticle itself Horr has further suggested that vapor adsorption due to capillary condensation may occur at the fiber cuticle scale edges, and that the phenomenon may contribute to the above interpretation that the wool surface is not entirely methyl. Horr also found that the possible composition of the wool fiber surface may even vary depending on the liquid with which it is in contact (e.g., water or methylene iodide). 

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