Modeling Interactions in Concentrated Ceramic Suspensions Under AC Electric Field

Colloidal processing of ceramics manipulates the interaction forces using additives or external energy field between the suspending particles to fabricate complex structures. Under AC electric field, mutual dielectrophoretic (DEP) forces between particles create particle chaining. Dielectrophoresis (DEP) is adopted to control ceramic particles in the colloidal suspension, which can benefit from employing DEP forces to externally control the fabrication of ceramic materials with desired porosity and hierarchical structure. To this end, it is crucial to understand the interactions between ceramic particles in aqueous media and AC electric field. The dynamic interactions of ceramic particles under AC electric field are modelled using the iterative dipole moment (IDM) method, which was first validated by the Maxwell stress tensor (MST) method. The IDM method has the capability to simulate the field-particle interactions and formation of particle chains for large number of ceramic particles in aqueous media. The DEP assembly of ceramic particles is investigated as functions of the frequency of the applied electric field, initial particle distribution, electric properties of ceramic particles and composition of the ceramic suspension. The quantitative analysis of particle cluster formation and the particle packing analysis of the particle distribution at the end of the simulation using electric field distribution and Voronoi diagrams provide insights into the effect of AC DEP on large number of particles. The DEP induced particle interactive motion is observed to create interconnected particle clusters concentrated in the center of the domain or graded structure with alternating dense and sparse regions depending on the material type and composition of the ceramic suspension