On the Problem of Acid-Base Interaction Determination for Weakly Polar Solids: Cholesterol Surfaces

✍ Scribed by E. Chibowski; M.L. Kerkeb; F. González-Caballero

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 451 KB
• Volume: 155
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1993.1058

✦ Synopsis

The problem of experimental determination of the true acidbase, electron acceptor, (\gamma_{\bar{s}}^{+}), and electron donor, (\gamma_{\bar{s}}^{\bar{s}}), components of the surface free energy of a weakly polar solid is made apparent for cholesterol by the different values of these components, obtained from contact-angle measurements of cholesterol pellets and of a thin layer of cholesterol deposited on a glass slide from solution in chloroform after chloroform evaporation, and also from thin-layer wicking. In these experiments, the following liquids were used: (\boldsymbol{n})-octane, (\boldsymbol{n})-decane, diiodomethane, bromoform, (\alpha)-bromonaphthalene, formamide, ethylene glycol, and water. Although the most probable values of the surface free energy components, (\gamma_{\mathrm{s}}^{\mathrm{LW}}=48.8, \gamma_{\mathrm{S}}^{+}=4.2), and (\gamma_{\bar{s}}=0 \mathrm{~mJ} / \mathrm{m}^{2}), are given, the problem of their determination is still open. 1993 Academic Press, Inc.