Pattern Formation Dynamics in Diverse Physico- Chemical Systems

Complex reaction-transport dynamics can lead to the formation of ordered structures. A constant dissipation of free energy is a requirement for sustaining macroscopic order, especially in solution. In the solid phase, the evolved pattern can be locked for days, months or even years. Liesegang bands are stratified stripes of precipitate that appear and persist, when co-precipitate ions interdiffuse in a gel medium. A host of interesting properties characterize such rich dynamical systems: band spacing laws (direct and revert), band splitting, rhythmic multiplicity, multiple precipitate formation and band redissolution are but a few manifested characteristics, emerging from a complex dynamics with a great diversity of scenarios. The familiar and well-known band formation in rocks could be the result of a complex coupled diffusion-percolation-chemical reaction mechanism. Similarities between geochemical self-organization and the Liesegang phenomenon are surveyed and analyzed. The simulation of band generation in a rock bed is realized and carried out in- situ, by injection and infusion of the reactant components into the rock medium. Ramified, tree-like structures (dendrites) are obtained during the electrodeposition or simple electroless redox deposition of metal systems. A great variety of morphologies