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Equation Zisman

A requirement underlying the validity of Zisman plots is that there be no specific interactions, such as acid-base interactions, between the solid surface and the probe liquids. Such interactions, however, can, in principle, be taken into account by Young s equation, provided the contact angle remains finite. Their... [Pg.24]

Jarvis, N.L. and Zisman, W.A. "Surface Activity of Fluorinated Organic Compounds at Organic-Liquid/Ari Interfaces Part III. Equation of State of Adsorbed Monolayers and Work of Adsorption of a Fluorocarbon Group," Naval Research Labs Report 5401, Surface Chemistry Branch, Chemistry Division, November 17, 1959. [Pg.675]

Early in the history of polytetrafluoroethylene, W. A. Zisman recognized its unusual surface properties, and the polymer now finds many uses because its low coefficient of friction eliminates the need for lubrication (Fitzsimmons and Zisman). Shooter and Thomas called attention to the remarkable resistance of polytetrafluoroethylene to seizure, and Bowden (1950) described use of composite structures. These and other investigations have been reviewed and summarized by Allan (1958) (also Allan and Chapman), who showed that the dependence of the coefficient of kinetic friction, fk, on the load in grams, W, is given by the following equation ... [Pg.484]

To determine yc for a solid, the advancing contact angles made by several non-polar or weakly polar liquids are measured and the value of Tlg which corresponds to 0 = 0 (i.e. cos 6=1) is found by graphical extrapolation. Zisman has determined yc for many solid surfaces by way of empirical plots of cos 0 versus -yLG (see Figure 6.2). According to equation (6.6), however, plots of cos 0 versus (Tlg)-1/2 should be approximately linear and permit more reliable extrapolation to cos 0=1. [Pg.153]

By Zisman s (6) definition, yi = y, the critical sxurface tension for wetting, when cos = 1, and under these conditions Equation 4 becomes... [Pg.145]

Wenzel s relation has been confirmed in terms of the first two laws of thermodynamics. Huh and Mason, in 1976, used a perturbation method for solving the Young-Laplace equation while applying Wenzel s equation to the surface texture. Their results can be reduced to Wenzel s equation for random roughness of small amplitude. They assume that hysteresis was caused by nonisotropic equilibrium positions of the three-phase contact line, and its movement was predicted to occur in jumps. On the other hand, in 1966, Timmons and Zisman attributed hysteresis to microporosity of solids, because they found that hysteresis was dependent on the size of the liquid molecules or associated cluster of molecules (like water behaves as an associated cluster of six molecules). [Pg.326]

Contact angle data, and the surface tensions of the test liquids, were taken from the work of Zisman et aL [4, 5, 8,9,14,15,22]. Data for the computation of 4>, to use in Equation 11, were from the following sources Ionization energies were from Field and Franklin [ll] and (for fluorocarbons) from Reed [28]. Dipole moments were taken from Sm3dli [29] and from the compilation of Wesson [30]. Polarizabilities were computed from refractive indices by the formula... [Pg.78]

Chen et al. (1999) treated polyester films with plasma in six kinds of gases (O, Nj, He, Ar, H, and CH ). Results in terms of surface tension and three components, and and the critical surface tension of the polyester film are summarized in Table 3.9 (Chen et al., 1999). It is evident that the value of the surface tension of polyester film obtained by the extended Fowkes s equation (Fowkes, 1964) corresponds highly to y of Zisman s plots (Zisman, 1964), which coincides with the theory of (Kitazaki and Hata (1972). Surface tensions of polyester films treated with O, ... [Pg.80]

In the second part of Equation 2.19, the fact that wetting hquids always have k equal to zero (Bascom et al., 1964 Fox and Zisman, 1950 Johnson and Dettre, 1966) has been used. [Pg.69]

Obtain an expression for the work of adhesion for nonwetting liquids using the Zisman equation (Equation 2.20). What will be the value of when y = yf Show that has a maximum. Find its... [Pg.98]

Solid surface properties based on contact-angle data for selected homopolymers are shown in Tables 59.3 and 59.4. The column of Table 59.3 is the Zisman critical surface tension of wetting [4] obtained from the quasistatic, advancing contact angles 0 of a series of liquids of surface tension 7lv by empirical equation ... [Pg.1015]

Table 59.3 is based primarily on the Zisman critical surface tension of wetting and Owens and Wendt approaches because most of the polymer data available is in these forms. The inadequacies of equations such as Eq. (59.7) have been known for a decade, and newer, more refined approaches are becoming established, notably these of van Oss and coworkers [24]. A more limited number of polymers have been examined in this way and the data (at 20 °C) are summarized in Table 59.4. is the component of surface free energy due to the Lifshitz-van der Waals (LW) interactions that includes the London (dispersion, y ), Debye (induction), and Keesom (dipolar) forces. These are the forces that can correctly be treated by a simple geometric mean relationship such as Eq. (59.6). y is the component of surface free energy due to Lewis acid-base (AB) polar interactions. As with y and yP the sum of y and y is the total solid surface free energy, y is obtained from... [Pg.1015]

Zisman and co-workers showed [22,23] that contact angle measurements could be used to determine a criterion for wettability as well as surface tension of a solid. In their experiments, a series of testing liquids of known surface tension were used to measure contact angles against a solid. A linear or quasi-linear relationship was found between the cosine of the contact angle made by a liquid and the surface tension of the liquid. The linear relationship could be extrapolated to cos 0 = 1 (or 0 = 0). The intercept of the line at cos 0 = 1 is considered to be the critical surface tension (7c) of the solid, and the plot of cos 0 versus yiv is known as the Zisman plot. When cos 0 = 1 and yc = yiv. Equation (lb) can be rewritten as... [Pg.168]

The original work of Zisman was developed by several workers. Using Young s equation, two problems exist. Firstly, even in a vapour atmosphere, the term ysF (or ksv) does not correspond necessarily to the surface tension of the solid ys- Whereas ys corresponds to the surface tension of the clean solid, ysv refers to the same quantity after any potential adsorption (see Adsorption theory of adhesion) of the vapour of the Uquid. The difference, always positive or zero, is called the spreading pressure Tt, with sufOx e representing equilibrium ... [Pg.512]

Zisman took care not to equate Yc with either Yso Ysv regarded it as an experimentally measurable characteristic of the surface, related to the surface energy. Other workers have been less careful in this respect. [Pg.135]

The purpose of this chapter is to present the LAD performance experiments carried out in room temperature liquids. Bubble point and reseal pressure tests for a 325x2300, 450 X 2750, and 510 x 3600 Dutch Twill screen are conducted in storable liquids, methanol, acetone, IPA, water, and binary methanol/water mixtures of various methanol concentrations. First screen pore diameters are estimated based on analysis from scanning electron microscopy and historical data. Experimental results are used to compare methods for determining effective pore diameter. Next, contact angles are measured for both pure and binary mixture fluids using a modified version of the Sessile Drop technique. Then, the equation of state analysis from Neumann and Good (1979) is used to determine the critical Zisman surface tension for stainless steel LAD screens, which... [Pg.87]

Equation (3.16) clearly predicts that bubble point pressure should scale linearly with the surface tension of the liquid when corrected for the contact angle between liquid and screen pore. Binary mixture bubble point test results from Chapter 4 showed that the critical Zisman surface tension value for liquids with these SS304 LAD screens was... [Pg.127]

Since relative to water for several halogenated aromatic n-alkane series could be determined, some additional surface chemical properties for these same series were calculated. The concepts of these properties and the appropriate equations had been developed by Pomerantz, Clinton and Zisman. Table V lists the initial film pressure (where ba..= Sba denotes the respective organic... [Pg.73]


See other pages where Equation Zisman is mentioned: [Pg.376]    [Pg.112]    [Pg.141]    [Pg.147]    [Pg.257]    [Pg.17]    [Pg.332]    [Pg.55]    [Pg.71]    [Pg.158]    [Pg.158]    [Pg.164]    [Pg.168]    [Pg.30]    [Pg.34]    [Pg.35]    [Pg.23]    [Pg.323]    [Pg.112]    [Pg.95]    [Pg.64]    [Pg.70]    [Pg.50]    [Pg.8096]    [Pg.120]    [Pg.12]    [Pg.138]    [Pg.139]    [Pg.139]   
See also in sourсe #XX -- [ Pg.453 ]




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