Turing Patterns

• Reaction must have sufficient feedback to support oscillations in batch reactor (but operate under conditions for which steady state is stable)

• Feedback species must have lower diffusivity than other species in reacting mixture (“diffusion-driven instability”)

• Must have continuous supply of fresh reactants (open, unstirred reactor)

• Must avoid fluid flow and convection (gels)

Gel Strip reactor:

Castets et al., 1990, Phys. Rev. Lett., 64, 2953.

Gel disk reactor

Ouyang and Swinney

1991, Chaos, 1, 411.