A Theory of One-Dimensional Liesegang Phenomena

The mechanism of formation of the rhythmic pattern of precipitates in one-dimensional Liesegang phenomena is investigated quantitatively. The outerelectrolyte diffuses into the gel which is impregnated with the innerelectrolyte, leaving the insoluble reaction product as hydrophobic sol particles. Diffusion proceeds as an advance of a contact surface of two electrolytes. The advance of the sol front is studied theoretically. Flocculation occurs suddenly when the total ionic concentration at the end of a sol region exceeds the flocculation value. Flocculation spreads rapidly in the region till it reaches the head of it, when proceeding stops. And from here the next sol region begins to spread. The estimation of the flocculation value is made and the proceeding meachanism of the flocculation front is theoretically investigated. By the periodic repetition of these phenomena, the periodicity and the spacing and time laws can be fully explained quantitatively.