A Study of Autophobic Liquids on Platinum by the Contact Potential Method

摘要

Several nonsprcading liquids were investigated on a platinum surface using contact potential and contact angle measurements to determine whether or not their nonsprcading behavior was caused by "aulophobicity." i.e. the property of a liquid being unable to spread upon its own adsorbed monolayer.. The liquids studied were n-octanol. n-octanoic acid, tri-p-cfesyl phosphite, mixed mot a- and para-isomers of tricresyl phosphate, methylene iodide, and three chlorinated biphenyls. Each liquid was shown to be autophobic by the contact potential difference arid contact angle data for adsorbed monolayers on platinum. Contact potential differences for the phosphate and phosphite were the same, indicating that the two types of molecules have different mechanisms of surface interaction with the metal surface. It was also found that raising the relative humidity affects the autophobic contact angle of liquid n-octanoic acid, n-octanol, and methylene iodide, but the effect is opposite in sign for the methylene iodide. This result sheds considerable light on the effect of water adsorption on the adsorptive properties of halogen derivatives of the hydrocarbons.