Heterogeneous nucleation of a monomer gas on a growing gas-phase polymer

We present a new theory for the nucleation of gas-phase monomers in a super saturated vapor on a growing short-chain polymer. Reiss and co-workers have shown that cloud chambers can be extraordinarily sensitive detectors of si ngle molecules of particular size in such experiments, giving valuable info rmation about rate constants for gas-phase polymerization. We have used a d ensity functional approach to calculate the free energy and heterogeneous n ucleation rate of liquid drops of monomer on oligomer chains of varying len gth. We show that the free energy is not a simple monotonic function of cha in length as assumed in simple classical theories. (C) 1999 American Instit ute of Physics. [S0021-9606(99)51719-4].