Effect of interfacial tension on propagating polymerization fronts

This paper is devoted to the investigation of polymerization fronts convert ing a liquid monomer into a liquid polymer. We assume that the monomer and the polymer are immiscible and study the influence of the interfacial tensi on on the front stability. The mathematical model consists of the reaction- diffusion equations coupled with the Navier-Stokes equations through the co nvection terms. The jump conditions at the interface take into account the interfacial tension. Simple physical arguments show that the same temperatu re distribution could not lead to Marangoni instability for a nonreacting s ystem. We fulfill a linear stability analysis and show that interaction of the chemical reaction and of the interfacial tension can lead to an instabi lity that has another mechanism: the heat produced by the reaction decrease s the interfacial tension and initiates the liquid motion. It brings more m onomer to the reaction zone and increases even more the heat production. Th is feedback mechanism can lead to the instability if the frontal Marangoni number exceeds a critical value. (C) 2000 American Institute of Physics. [S 1054-1500(00)01701-8].