Formation of Liesegang Patterns: A Spinodal Decomposition Scenario

Spinodal decomposition in the presence of a moving particle source is proposed as a mechanism for the formation of Liesegang bands. This mechanism yields a sequence of band positions $x_n$ that obeys the spacing law $x_n\sim Q(1+p{)}^n$. The dependence of the parameters $p$ and $Q$ on the initial concentration of the reagents is determined and we find that the functional form of $p$ is in agreement with the experimentally observed Matalon-Packter law.