Contact angle adhesion

Time dependence of the PF adhesive contact angle (°) for the control and heat-treated wood specimens... 

The work of adhesion (see Wetting and work of adhesion. Contact angles and inter-facial tension) is a simple example of a concept that could be regarded as a fundamental measure of adhesion between two surfaces. 

Related articles are Adsorption theory of adhesion. Contact angles and interfacial tension. Dispersion forces. Pre-treatment of metals prior to bonding. Roughness of surfaces. Surface characterization by contact angles-polymers. Surface energy and Wetting and spreading. 

Keywords Surface free energy, test inks, dyne pens, plasma treatment, adhesion, contact angle... 

Work of Adhesion Contact Angle Inter dal Tension... 

Mechanical adhesion Specific adhesion Contact angle Critical surface tension Photoresists Microlithography Negative and positive resists... 

Using the data of Table X-2, estimate the contact angle for benzene on aluminum oxide and the corresponding adhesion tension. 

Water at 20°C rests on solid naphthalene with a contact angle of 90°, while a water-ethanol solution of surface tension 3S dyn/cm shows an angle of 30°. Calculate (a) the work of adhesion of water to naphthalene, (b) the criticd surface tension of naphthalene, and (c) y for naphthalene. 

D. Platikanov and M. Nedyalkov, Contact Angles and Line Tension at Microscopic Three Phase Contacts, in Microscopic Aspects of Adhesion and Lubrication, J. M. Georges, ed., Elsevier, Amsterdam, 1982. 

D. Y. Kwok, F. Y. H. Lin, and A. W. Neumann, Contact Angle Studies on Perfect and Imperfect Solid Surfaces, in Proc. 30th Int. Adhesion Symp., Yokohama Japan, 1994. 

The interesting implication of Eq. XII-24 is that for a given solid, the work of adhesion goes through a maximum as 7b(a) is varied [69]. For the low-energy surfaces Zisman and co-workers studied, )3 is about 0.04, and Wmax is approximately equal to the critical surface tension yc itself the liquid for this optimum adhesion has a fairly high contact angle. 

Returning to more surface chemical considerations, most literature discussions that relate adhesion to work of adhesion or to contact angle deal with surface free energy quantities. It has been pointed out that structural distortions are generally present in adsorbed layers and must be present if bulk liquid adsorbate forms a finite contact angle with the substrate (see Ref. 115). Thus both the entropy and the energy of adsorption are important (relative to bulk liquid). The... 

Derive from Eq. XU-24 an expression for the maximum work of adhesion involving only and 7c. Calculate this maximum work for 7c = 22 dyn/cm and 0 = 0.030, as well as 7/. for this case, and the contact angle. 

Contact Angle, Wettability and Adhesion , Adv. Chem. Series No. 43, Amer. Chem. Soc. (1964). 

The wettabiHty theory of adhesion is iaextricably related to the study of contact angles of Hquids on soHd surfaces. A force balance at the poiat of contact between the Hquid and the soHd can be written (3)... 

In the pendular state, shown in Figure la, particles ate held together by discrete lens-shaped rings at the points of contact or near-contact. For two uniformly sized spherical particles, the adhesive force in the pendular state for a wetting Hquid (contact angle zero degree) can be calculated (19,23) and substituted for H. in equation 1 to yield the foUowing, where y is the Hquid surface tension in N/m. 

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