ON THE NATURE OF PATTERNS ARISING DURING POLYMERIZATION OF ACRYLAMIDEIN THE PRESENCE OF THE METHYLENE-BLUE SULFIDE-OXYGEN OSCILLATING REACTION

Transient Turing-like spatial patterns were recently reported by Munst er et al. when the components of the methylene blue oscillator are mix ed with acrylamide and a polymerization initiator to form a polyacryla mide gel. We have qualitatively reproduced these results, but we demon strate that, although the observed patterns have the appearance of Tur ing structures, they actually result from Rayleigh-Benard convection i n a mixture of acrylamide, N,N'-methylene-bisacrylamide, triethanolami de, sulfide ions and ammonium peroxodisulfate during the polymerizatio n and gelation process. Neither methylene blue nor sulfite is required for patterns to develop. (C) 1998 Published by Elsevier Science B.V. All rights reserved.