Receding contact angle interfacial tension

The hysteresis of the polymer-water free energy of adhesion was calculated from H = y , (cos0r — cos 0 ). where ywll is the water-air interfacial tension and 0r the receding contact angle. 

To quantify the effects of mixed waste con sition on wettability and interfacial tension equilibrium, aqueous phase receding contact angle and interfacial tension were measured. Inter cial tension was measured ida a spinning drop tensiometer Model 500 (University of Texas, Austin, TX) and contact angles were obtained using axisymmetric drop shape analysis (17) on quartz slides. Contact angles are reported through the aqueous phase. 

Figure 14.9. Typical experimental results obtained for dynamic contact angle measurements of -dodecane on a silicon wafer (a) contact angle (b) contact radius (c) volume (d) liquid-vapour interfacial tension of the drop. / a is the rate of advancing of the drop front, while Rf is the rate of receding of drop front (from ref. (40))...

---