Desiccation and Relaxation Regimes in Fracture of Drying Clay Films

TL;DR

This paper investigates crack pattern formation in drying clay films, revealing two distinct regimes with different vertex types and a self-similar pattern that scales with film thickness.

Contribution

It identifies and characterizes two cracking regimes in drying clay films and demonstrates their self-similar scaling behavior with respect to film thickness.

Findings

Two cracking regimes with different vertex types identified

Crack patterns exhibit self-similarity under coarse-graining

Crack area scales with film thickness and collapses onto a single curve

Abstract

A study of crack patterns in laponite films of different thickness is presented. Two cracking regimes are observed. The earlier with a higher rate of desiccation and shrinking has predominantly four-fold vertices in the crack network, while the later regime has less volume shrinking and forms mainly three-fold vertices. The pattern shows a self-similarity under coarse-graining. The graph of area covered by the cracks versus minimum crack-width resolved, scales with the film thickness. Curves representing crack area for different thickness can thus be made to collapse onto a single curve.