Determination of ultrahyphen;low vapor pressures by submicron droplet evaporation

摘要

Vapor pressures as low as of order 10minus;8mm Hg (10minus;10atm) have been determined by measuring the diffusionhyphen;controlled evaporation rates of single submicron droplets suspended in an electric field in the path of a laser beam. Using Mie theory to ascertain the droplet radius as a function of time from lighthyphen;scattering data, the vapor pressures of dioctyl phthalate (DOP), dibutyl sebacate (DBS), and dibutyl phthalate (DBP) have been determined at temperatures near room temperature. In addition to vapor pressures, heats of vaporization and Lennardhyphen;Jones molecular interaction parameters are determined from the experiments.