On the nature of patterns arising during polymerization of acrylamide in the presence of the methylene blue-sulfide-oxygen oscillating reaction

Transient Turing-like spatial patterns were recently reported by Münster et al. when the components of the methylene blue oscillator are mixed with acrylamide and a polymerization initiator to form a polyacrylamide gel. We have qualitatively reproduced these results, but we demonstrate that, although the observed patterns have the appearance of Turing structures, they actually result from Rayleigh–Benard convection in a mixture of acrylamide, N,N′-methylene-bisacrylamide, triethanolamide, sulfide ions and ammonium peroxodisulfate during the polymerization and gelation process. Neither methylene blue nor sulfite is required for patterns to develop.