A RADIOACTIVE TRACER STUDY OF THE ADSORPTION OF FLUORINATED COMPOUNDS ON SOLID PLANAR SURFACES. II. C₈F₁₇SO₂N(C₂H₅)CH₂COOH

Upper Limits for the Contact Angles of Liquids on Solids

“…Since the cos ö-vs-N data for hexadecane on perfluorinated acid monolayers also are essentially linear, they can be extrapolated to the same value of N and they indicate a maximum contact angle of 92°. This is larger than the 78° observed experimentally on perfluorolauric acid monolayers but is still considerably smaller than the 109° predicted as the limiting angle on a surface of y c -0, These values are of interest when compared with the contact angles recently reported by Ryan, Kunz, and Shepard (46) for N-ethyl-N-perfluorooctanesulfonylglycine monolayers chemisorbed on the one metal, aluminum. Their hexadecane contact angle of 110° is larger than any previously reported and is close to the limiting maximum indicated in Fig.…”

“…The smallest water angle reported on a surface not dissolved by or permeable to molecular water is 68° on a single crystal of cyclotrimethylene trinitramine (y,, = 44 dynes/cm) (45). With solvent action by water, of course, the contact angle drops rapidly, as in the case of polyvinyl alcohol despite the value of y c of 37 dynes/cm reported by Ryan et al (46).…”

The effect of autoxidation on the wettability of a linoleic acid monolayer

“…The interfacial tension, ySL, would then be near zero and the contact angle would be lower than expected. Other authors have expressed similar views (46)(47)(48). Whether the overturning of the molecules is the only factor involved in the contact angle decrease has never been definitely proven.…”

“…Shepard and Ryan (46,47 ) found that contact angles between water and glycerol and a perfluorooctanoic acid monolayer were determined largely by the substrate as shown in Table I. Autoradiographs of radioactive perfluorooctanoic acid monolayers, after removing the liquid drops, showed that the monolayer was "desorbed" by the polar liquids, the greatest depletion being when the monolayers were on the glass.…”

Electrode–Electrolyte Interfacial Processes in Ionic Liquids and Sensor Applications

“…The past decades have been characterized by a spectacular development of in situ techniques for studying interfacial processes at metal electrodes. Radioactive tracer [31,32], pulse potentiodynamic [33,34], and galvanostatic methods [35] have been applied quantitatively to study the adsorption of organic compounds at solid metals. In the study of complex electrode reactions, vibrational spectroscopies, such as Raman [36][37][38][39][40], the infrared (IR) [41][42][43], and UV-vis spectroscopies [44,45], have been used to identify adsorbed intermediates and the nature of the chemisorption bond [46].…”