title: Electric-field-induced crack patterns: experiments and simulation.
abstract: We report a study of crack patterns formed in laponite gel drying in an electric field. The sample dries in a circular petri dish and the field is radial, acting inward or outward. A system of radial cracks forms in the setup with the center terminal positive, while predominantly cross-radial cracks form when the center is at a negative potential. The laponite accumulates near the negative terminal making the layer thicker at this end. A spring model on a square lattice is used to simulate the desiccation crack formation, with an additional radial force acting due to the electric field. With the radial force acting outward, radial cracks form and for the reversed field cross-radial cracks form. This conforms to the observation that laponite platelets become effectively positive due to overcharging and are attracted towards the negative terminal.
authors.affiliation: Condensed Matter Physics Research Centre, Physics Department, Jadavpur University, Kolkata 700032, India.
authors.forename: Tajkera
authors.initials: T
authors.lastname: Khatun
authors.forename: Moutushi Dutta
authors.initials: MD
authors.lastname: Choudhury
authors.forename: Tapati
authors.initials: T
authors.lastname: Dutta
authors.forename: Sujata
authors.initials: S
authors.lastname: Tarafdar
mesh_terms: D003198:Computer Simulation; D004574:Electromagnetic Fields; D005782:Gels / Q000737:chemistry* / Q000528:radiation effects*; D006244:Hardness / Q000528:radiation effects; D008956:Models, Chemical; D011829:Radiation Dosage; D017640:Silicates / Q000737:chemistry* / Q000528:radiation effects*; D013314:Stress, Mechanical; D013499:Surface Properties / Q000528:radiation effects; D013718:Tensile Strength / Q000528:radiation effects
chemical_list: D005782:Gels; D017640:Silicates; C524813:laponite