Some controversions in the characterization of the physicochemical condition of the polymer surface
Polimery 2001, No 11-12, 785
The generally adopted method of determining the physicochemical condition of the surface of solids, including polymers, from contact angle measurements, is critically evaluated. Errors involved in the contact angle measuring method, the contact angle hysteresis and the oversimplifications often resorted to, are specified. The models developed by Fowkes (eqn. 7) , Chang-Chen (eqn. 14) , and particularly by Good-van Oss-Chaudhury (GvOC, eqn. 11)  are described. Typical errors made in selecting the test liquid to be used to measure the contact are pointed out. Surface titration is reanalyzed as a method for determining the surface concentration of dissociable groups. The method is believed to offer an alternative approach to establishing the nature of the surface. Reasons are reminded  for which the dissociation of the groups residing at the surface of a polymer differs essentially from the dissociation of these groups occurring in aqueous solutions of their low-M analogs. Surface titration is believed to be a reliable method of estimating the surface concentration. Author's own estimation procedure is presented in detail (eqn. 19, table 3).
Keywords: surface tension, contact angle measurement, models of surface phenomena, surface titration of surface-borne ionogens