Heteromolecular condensation

Hamill, P. (1975). The time dependent growth of H20-H2S04 aerosols by heteromolecular condensation. J. Aerosol Sci. 6, 475-484. 

In this section, we study gelation by heteromolecular condensation reaction in binary mixtures. Typical model systems are condensation of /-functional monomers of the type R A/ and g-functional monomers of the type R Bg. They form binary mixed networks. The mixtures are indicated by R A/ /R Bg. For simplicity, the reaction is limited to only between the A and B functional groups (Figure 3.12). 

Stauffer, D. (1976) Kinetic theory of two-component ( heteromolecular ) nucleation and condensation, J. Aerosol Sci. 7, 319-333. 

We see that at the lower SO2 conversion rate, the characteristic time for nucleation to occur greatly exceeds that for condensation so the latter can be expected to predominate as the mechanism for gas-to-particle conversion. At the higher production rate at high humidities, the nucleation time can actually become shorter than the condensation time, indicating that heteromolecular nucleation can be expected to become important under these conditions. 

Homogeneous nucleation is the formation of the condensed phase (particles) from purely gaseous molecules. If only a single molecular species is involved, the process is termed homomolecular, while it is called heteromolecular when more than one such species participates. Aspects of homogeneous nucleation depend to a great extent upon collision rates this leads to highly mixed results upon treatment by kinetic theoretic means. Undoubtedly, any ultimate description will necessitate details not only of kinetics but also of dynamics and microparticle microphysics to account for the rates and structure of critical (i.e., stable) cluster formation. 

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