Contrasting physical adsorption behavior between fluorocarbons and fluorocarbon derivatives on zinc oxide

Abstract

Adsorption isotherms for a number of fluorocarbons and fluorocarbon derivatives were determined on zinc oxide adsorbents. The isotherms for the fluorocarbons at less than monolayer coverage differed markedly from those for fluorocarbon derivatives. After completion of the monolayer, fluorocarbons showed Type II behavior. Fluorocarbon derivatives gave only Type II isotherms both above and below monolayer coverage. The irregular shape of the fluorocarbon isotherms below monolayer coverage can be attributed to two-dimensional phase transitions.