Title : Electrically controlled droplet formation in charged colloidal suspensions using microfluidics

Charged colloidal suspensions are promising soft materials for developing controllable microfluidic systems. In this work, we investigate how a DC electric field affects the formation of droplets from a negatively charged colloidal suspension in a microfluidic T-junction. The colloidal suspension was used as the dispersed phase with an immiscible oil as the continuous phase. The same microfluidic geometry, materials, flow conditions, and experimental setup used for the conventional electrolyte system were maintained, allowing a direct comparison of the two systems. Experiments were performed at different applied DC voltages, and the resulting changes in droplet shape, interface deformation, neck formation, and breakup were observed using microscopy. Increasing the applied voltage produced clear changes in the droplet formation and breakup behavior. These changes are attributed to the combined effects of electric-field-induced particle migration, interfacial polarization, and electrohydrodynamic stresses. The results provide new insight into how charged colloids interact with fluid interfaces under electric fields and demonstrate the potential of this approach for producing electrically tunable colloidal microcompartments. Such microcompartments may be useful for future cell-free biochemical reactions and artificial-cell systems.

Dr. Raheema is an experienced higher education faculty and researcher with around 12 years of international teaching and research experience in physics. She has PhD in complex systems and colloidal materials majoring in Physics. She has worked on Colloidal Phase Transition Dynamics under external electric and magnetic fields at University of Navarra Spain and experimental studies of melting colloidal crystals in suspension influenced by external fields at Johannes Gutenberg University Mainz, Germany. She is currently Engineering faculty member at Higher Colleges of Technology, United Arab Emirate.