Influence of Soluble Surface-Active Organic Material on Droplet Activation

Abstract

Both theoretical and experimental approaches also show that despite the a depression, S$\sb{\rm c}$ of a particle that contains SDS is always higher than that of a pure NaCl particle with the same dry size. The degree of this deviation increases with increasing SDS% in the mixtures, indicating an increase in hydrophobicity with increasing SDS% in the initially dry particles. The lowering of Raoult effect due to the large molecular weight of SDS is attributable to this trend. It appears that in the atmosphere, only those particles that contain soluble surfactants, whose molecular weight is comparable to (NH$\sb4)\sb2$SO$\sb4$ and meanwhile are very surface active, can achieve low S$\sb{\rm c}$ comparable to that of (NH$\sb4)\sb2$SO$\sb4$ particles.