Hydrodynamic stability of a polymerization front

We consider the propagation of an exothermic reaction wave which converts liquid reactants into a solid product. Such reaction waves are observed, for example in addition polymerization, where there is a propagating localized polymerization zone, in which monomer is converted to polymer. We study uniformly propagating travelling waves and their linear stability. We show that, though this problem is similar to the problem of gaseous combustion, which exhibits a hydrodynamic instability, here there is no such hydrodynamic instability. This theoretical result is consistent with experimental observations in the case when the polymerization process occurs under high external pressure conditions.