Wetting measurements

The study of acid-base interaction is an important branch of interfacial science. These interactions are widely exploited in several practical applications such as adhesion and adsorption processes. Most of the current studies in this area are based on calorimetric studies or wetting measurements or peel test measurements. While these studies have been instrumental in the understanding of these interfacial interactions, to a certain extent the interpretation of the results of these studies has been largely empirical. The recent advances in the theory and experiments of contact mechanics could be potentially employed to better understand and measure the molecular level acid-base interactions. One of the following two experimental procedures could be utilized (1) Polymers with different levels of acidic and basic chemical constitution can be coated on to elastomeric caps, as described in Section 4.2.1, and the adhesion between these layers can be measured using the JKR technique and Eqs. 11 or 30 as appropriate. For example, poly(p-amino styrene) and poly(p-hydroxy carbonyl styrene) can be coated on to PDMS-ox, and be used as acidic and basic surfaces, respectively, to study the acid-base interactions. (2) Another approach is to graft acidic or basic macromers onto a weakly crosslinked polyisoprene or polybutadiene elastomeric networks, and use these elastomeric networks in the JKR studies as described in Section 4.2.1. 

In-line metrology is a process control method suitable for regulating dielectric CMP. There are two major methodologies in use for in-line metrology wet and dry. Wet measurements involve immersing each wafer in DI water immediately after polishing it and measuring the amount... 

Hutchinson and Manchester (7o) and Kiselev et al. (7b) also recently designed calorimeters for wetting measurements based on platinum resistance thermometers. 

In spite of the above mentioned difficulties, sensitivities of the order of 0.01 cal. can be obtained in heats of wetting measurements. The precision and accuracy of such measurements are determined mainly by the surface area of the powder, as mentioned earlier, its surface energy and cleanliness, and the polarity and purity of the wetting liquid. 

Wetting Measurements. Wetting measurements with water were made on copolymer films formed by evaporation of 3% by weight solutions of the copolymer from t-butanol, p-dioxane, and toluene. The films were formed on glass microscope slides and were the order of 10 microns in thickness. The films were allowed to form over a 24-hour period in a drying box at a relative humidity of 20%. 

Distributions in surface energy and its components often exist in practice, and these may be determined by the wetting measurements described here. 

The shapes of these isotherms are controlled by surface heterogeneity, and thus provide a means of deducing the various modes of interfacial attraction presented by the substrates. Isotherms of pentane on unsized IM6 before and after plasma treatment are congruent. Pentane interacts only by dispersion force attraction, as does methylene iodide the registry of these isotherms is predicted by the similarity in ft obtained from wetting measurements. Pentane isotherms serve as a reference with which to assess the effect of additional modes of solid/vapor interaction with acidic and basic probes. 

Zettlemoyer, A.C., Chessick, J.J., and HoUabaugh, C.M. (1958). Estimation of the surface polarity of solids from heat of wetting measurements. Phys. Chem., 62, 489-90. Morimoto, T. and Suda, Y. (1985). Heat of immersion of zinc oxide in organic liquids. 1. Effect of surface hydroxyls on the electrostatic field strength. Langmuir, 1, 239—43. 

Bismarck, A., Kumru, M.E., and Springer, J., Characterization of several polymer surfaces by streaming potential and wetting measurements Some reflections on acid-base interactions, J. Colloid Interf. Sci., 217, 377, 1999. 

Density Measured wet Measured dry Dry After 2h boil Cold-water... 

Panel density (g/cm ) Measured wet (%) Measured dry (irreversible swelling) (%) Original IB, tensile perpendicular (kg/cm ) IB after a 2-h boil (kg/cm ) Cyclic test after five cycles measured (%)... 

Region C is only observed above Jg and is attributed to the irreversible flow of polymer chains and perhaps some rubber-like extension of chains that are not highly oriented. The temperature dependence of the stress-strain curves measured in water and silicone oil are compared in Figure 12.44 and Figure 12.45, respectively. The measurements in silicone oil are assumed to be characteristic of the dry fiber, since the oil does not plasticize the fiber. The disappearance of the yield point indicates that a transition from the glassy to the rubbery state has occurred near 115 and 70°C in the dry and wet measurements, respectively this corroborates the strong plasticization effect of water that was discussed in Section 12.4. 

Interfacial free energy and heterogeneity of protein layers Wetting measurements... 

Figure 7.4. Single fibre wetting measurement geometry...

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