Dispersive surface energy component

The contact angle is measured in a series of liquids with varying polar and dispersion surface energy components. The components of the fiber surface energy can be determined by plotting the left-hand side of Eq. (7) as a function of of... 

Using this expression for water—hydrocarbons interfacial tension (y h) die dispersive surface energy component of water may be found. As basic components for hydrocarbons should be zero, the dispersive component is the surface tension of the hydrocarbon. Measuring yu, Yw> and YwH die only unknown is y which turns to be... 

Wu has proposed to separate the surface energy into non-polar (dispersion) and polar components (Eq. (2.12)). The subscripts d and p designate non-polar (dispersion) and polar components, respectively. The concept of the additive nature of surface energy components has been accepted by a number of researchers such as Fowkes ° and Meyer et al. The polar component of surface tension includes various dipole interactions and hydrogen bonding. The various components have been lumped together to simplify the discussions. The dispersion component includes the nonpolar fraction of surface energy. Fractional polarity is defined by Eq. (2.13) and non-polarity by Eq. (2.14). 

The article on Surface energy components describes how surface energies of solids and thence the work of adhesion between adhesive and substrate could be calculated from an assumption that the surface energy is composed of the sum of a dispersion and polar component (Eqn. 9 therein). Practical measurements of surface tensions of liquids and of contact angles of liquids on solids were involved. In a similar way, solid surface energies and works of adhesion can be obtained from the assumption (Eqns. 3 and 4 above) that surface energy is made up of the sum of a Lifshitz-van der Waals and an acid-base component. The term is obtained using non-polar liquids in exactly the same way as the dispersion components, y, were obtained. This article is concerned with expressions that can be used to represent acid-base interactions and which can then be used in equations such as 3 and 4 and those derived from them. 

An important point in the use of surface energy components is the realization that for non-polar liquids, such as alkanes, only dispersion forces act between molecules, so... 

Surface energy components D E PACKHAM Dispersion and polar components geometric mean relationships solid surface energies... 

The thick-flhn limit of the lubricant dispersion surface energy is yf = 13 mJ/m [22]. The dispersion component of the surface energy of the slider is Yi. For the uncoated slider, yf = 43 mJ / m, and the coated slider values are given in table 4.10. The adhesion stress is listed in table 4.13. Further discussion of adhesion-controlled friction is given in the literature [23]. 

Della Volpe and Siboni refuted the VOCG components model using Kwok s own experimental values. Della Volpe and Siboni argued that the determination of the solid surface energy components by the VOCG model could be ill-conditioned if any set of liquids were used to measure the contact angle with the solid. For example, if only pure dispersive liquids are employed, the accurate result of the acidic or basic components will never be obtained. The same would happen if Hquids with almost no basic components were used. 

Wher y and yi are the dispersive components of the solid surface and the interactive solutes phase, respectively. N is Avogadro s number and a is the area of the adsorbed molecules (solutes). In IGC experiments a series of interactive solutes, such as alkanes, can be injected into the chromatographic column in order to determine the dispersive surface energy, ys. A plot of AGi or (RT In Vg°) versus the number of carbons in the alkane chain can be meaningful, since such a plot is linear and the slope of the straight line will account for the incremental contribution of AGi. The molar enthalpy of adsorption can also be calculated from AGi as follows ... 

Table IV exemplifies the surface energy properties of some plasma polymers (data from Tables I and II, columns A) and their conventional counterparts. The surface energy components for conventional polymers were calculated from contact angle data of water/methylene iodide system reported by Shafrin et al. There are also specified the densities of plasma polymers and conventional amorphous counterparts, respectively. The data in Table IV clearly indicate that plasma polymers have higher surface energy as compared to their conventional counterparts. This apparently results from the increased dispersion and polar (except PP-VDC) components of their surface energy. The increase in y noted...

Fig. 17. A schematic of the alkane line obtained by inverse gas chromatography (IGC) measurements. The relative retention volume of carrier gas required to elute a series of alkane probe gases is plotted against the molar area of the probe times the. square root of its surface tension. The slope of the plot is yielding the dispersion component of the surface energy of...

Geometric mean approximation Dispersive and polar components of solid surface energy are found by solving yiv(l +COS0) = 2(y,Xf + 2(y Yl S An extension of GGF equation ysa predicted is significantly higher than the critical surface tension. [84]... 

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