Comment on "On the nature of patterns arising during polymerization of acrylamide in the presence of the methylene blue-sulfide-oxygen oscillating reaction" [Chem. Phys. Lett. 295 (1998) 70-74]

In their paper, the authors state that patterns emerging in the PA-MBO syst em are generated by hydrodynamic convection instead of a diffusion induced instability involving the chemistry of the nonlinear MBO reaction. In our o pinion, their findings can be explained by the use of improperly purified s ulfide in some cases and by a low concentration of oxygen in other instance s. Recent experiments and simulations performed by our group confirm our pr evious interpretation of the patterns in the PA-MBO system in terms of Turi ng structures. In particular, our work on the effects of an electrical fiel d and light on pattern formation proves the chemical origin of the patterns . (C) 1999 Elsevier Science B.V. All rights reserved.