A sequence of morphological transitions in two-dimensional dehydration patterns of aqueous solutions of ascorbic acid is observed with humidity as a control parameter. Change in morphology occurs due to humidity induced variation in the concentration of the metastable supersaturated solution phase formed after initial solvent evaporation. As percent humidity is varied from 40 to 80, patterns change from compact circular $\to$ radial $\to$ density modulated radial (a new morphology) $\to$ density modulated circular $\to$ density modulated dendritic (a new morphology) $\to$ dense branching.

• Received 19 November 2001

DOI:https://doi.org/10.1103/PhysRevLett.89.075504