Elucidating thixotropic behavior of aqueous colloidal slurries inducing cracks during drying

Abstract Cracks are a phenomenon found in various natural situations, yet they represent a long‐standing challenge as a critical defect in industrial fields. For instance, cracks formed during the drying of colloidal slurries lead to performance degradation and disruptions in processing. Although numerous experimental and theoretical approaches have been explored to understand and control crack formation, its complex mechanisms remain difficult to comprehend systematically. Here, we demonstrate a novel perspective that cracking can be understood through the thixotropic behavior of slurries. The elastic structural recovery that determines thixotropy is quantitatively evaluated using aqueous colloidal slurries with alumina particles as a model. Furthermore, this elastic force is shown to be highly sensitive to changes in particle dispersion. A key finding is the strong correlation between the elastic structural recovery of slurry and crack formation during drying. Based on the multifaceted experimental results, we elucidate the hidden physics of thixotropy as a crucial indicator of durability against drying‐induced stresses.