APPLICATION OF A MULTISTEP CONDENSATION NUCLEI COUNTER AS A DETECTOR FOR PARTICLE SURFACE COMPOSITION.

A method has been developed which is based on the influence of particle surface on the condensation process. An electrostatic classifier is used to generate a monodisperse aerosol of known electrical mobility diameter. The Kelvin equivalent diameter of this aerosol is then determined using a simple Nolan-Pollak type condensation nuclei counter which has been modified to run automatically through a series of different water vapour supersaturations. The comparison between the Kelvin size and the electrical mobility diameter of these monodisperse particles yields information on the surface structure of the particles.