Drying Colloids: Desiccation Cracks

The drying of colloidal dispersions and the subsequent formation of particulate films involve a complex physical process. Mechanical instability and structural defects, such as warping, buckling, and cracks, are common occurrences. These cracks, also known as desiccation cracks, exhibit various morphological forms influenced by drying conditions, physicochemical factors, and constituents of the drying process. Despite the known impact of particle shape on local microstructure and packing in the deposit, its influence on desiccation cracks was discovered. Exploring the potential to create ordered periodic structures in cracks through external field manipulation could advance lithographic fabrication protocols. Our study utilizes a sessile drop configuration in drying experiments to investigate and understand desiccation cracks [see Fig. 1].

Our main focus was to unravel the dependence of local structure and the macroscopic cracks that are formed in the dried particulate deposit. We looked across various directions:

1. Role of local structural anisotropy on desiccation cracks

2. External field, viz. electric, magnetic, thermal and magneto-thermal field on desiccation cracks

3. Interplay of substrate -particulate film elasticity on desiccation cracks

Our investigation reveals intricate correlation between desiccation cracks pattern and the local structure. 

Reference:

• Synergy between the crack pattern and substrate elasticity in colloidal deposits, Hisay Lama, Tonmoy Gogoi, Ludovic Pauchard, M. G. Basavaraj, Dillip K. Satapathy, Phys. Rev. E, 103, (3), 032602 (2021).

• Desiccation cracks in dispersion of ellipsoids: Effect of aspect ratio and applied fields, Hisay Lama, Madivala G. Basavaraj, Dillip K. Satapathy, Phys. Rev. Materials., 2(8), 085602 (2018).

• Cracks in dried deposits of hematite ellipsoids: Interplay between magnetic and hydrodynamic torques, Hisay Lama, Ranajit Mondal, Madivala G. Basavaraj, Dillip K. Satapathy, J Colloid Int. Sci., 510, 172 - 180 (2018).

• Tailoring crack morphology in coffee-ring deposits via substrate heating, Hisay Lama, Madivala G. Basavaraj, Dillip K. Satapathy, Soft Matter, 13, 5445-5452 (2017).  

• Role of particle shape anisotropy on crack formation in drying of colloidal suspension", Venkateshwar Rao Dugyala, Hisay Lama, Madivala G.    Basavaraj, Dillip K.Satapathy, Scientific Reports 6 (30708) (2016).

• Magnetic- field-driven crack formation in an evaporated anisotropic colloidal assembly", Hisay Lama, Venkateshwar Rao Dugyala, Madivala G. Basavaraj, Dillip K.Satapathy, Phys. Rev. E, 94 (1), 012618 (2016).