A new experimental method to analyse the dewetting properties of polymer surfaces and cationic surfactants

In the present paper a new method able to easily evaluate the critical height of rupture of liquid films on various substrate surfaces is described and commented. It is automatic and based on the different IR reflectance of solids and liquids. Its limits and advantages are analysed. The heights of rupture of water have been measured on different kinds of polymeric solid surfaces as well as on surfaces whose water repellency has been increased by different mixtures of substituted ammonium salts, used as autophobic rinse aids. In both cases the effect of experimental conditions and the value of contact angles measured by the Wilhelmy microbalance have been correlated with the height of rupture. The peculiar sawtooth trend of force versus immersion in Wilhelmy experiments, performed by using some of these autophobic substances solutions, is described and interpreted.