Physical Adsorption of Vapors.

The results of several series of investigations are reported. The nature of the ice-vapor interface has been studied at 77K, using nitrogen, argon, and carbon monoxide as adsorbates at -80C, with ethane and with carbon dioxide and at -30C to -40C, using n-pentane and n-hexane. At low temperatures, ice-surface is inert and non-polar at higher temperatures bulk phase reaction may occur with small adsorbate molecules to form the ice clathrate compound and with larger molecules, surface restructuring may occur. Other molecular solids were studied at 77K, and behave similarly to ice the adsorbent-adsorbate dispersion interaction is very weak in these systems. Adsorption at the ice-liquid n-hexane interface has been studied. Contact angle data have been obtained for carbon disulfide on ice as a function of temperature. It is proposed that solid-liquid interfaces be classed as A or B in type, depending on whether restructuring of the solid surface occurs. An adsorption model has been developed relating adsorption isotherms to contact angle and spreading behavior. Author