Mechanisms of bands and spirals formation during the drying of watery solutions of mercury (II) chloride with agar-agar

Abstract

It is proposed two mechanisms to explain the formation of periodic and non periodic bands and spirals as thin films of gelatinous aqueous solutions of mercury (II) chloride are dried. The first mechanism supposes an homogeneous drying, where the height of the film decreases at constant rate, forming Liesegang bands. The second mechanism implies a non homogeneous drying where an evaporation front drives the formation of periodic bands and spirals. © 2005 IOP Publishing Ltd.