We studied the pattern of cracks formed during the drying of a collodial suspension. Because of water evaporation, particles and ionic species accumulate near the surface and a gel forms and shrinks. In a confined geometry, the gel shrinkage leads to large stresses which are the cause of crack formation. For the 1D geometry used, we observe that the cracks are regularly spaced. Taking into account the competition between stress relaxation due to crack opening and stress increase due to water loss through the crack, we develop a simplified model which allows understanding of the observed pattern.

• Received 29 June 1994

DOI:https://doi.org/10.1103/PhysRevLett.74.2981