Silanes as cloud stabilizers

Silanes (alkylchlorosilicon compounds) are effective in stabilizing cloud droplets against evaporation. Among 14 compounds tested, the alkyltrichlorosilanes proved most efficient in this role. This mode of action is apparently a reaction of the silane with water at the surface of a droplet to form a silicone polymer film that lowers the water vapor pressure over the surface. The reduction of vapor pressure was demonstrated by experiments, which showed that the dewpoint is lowered in a silane-treated cloud and over a silane-treated plane water surface. Substances that are effective as cloud stabilizers were also found to be effective in preventing the nucleation of ice crystals but AgI ice nuceli in a supercooled cloud.