@article{NavakarAmiroudineMayuretal.2015, author = {Abhishek Navakar and Sakir Amiroudine and Manik Mayur and Evgeny A. Demekhin}, title = {Long-wave interface instabilities of a two-liquid DC electroosmotic system for thin films}, series = {Microfluidics and Nanofluidics}, volume = {19}, number = {4}, publisher = {Springer}, address = {Berlin, Heidelberg}, issn = {1613-4982}, doi = {10.1007/s10404-015-1606-0}, pages = {813 -- 827}, year = {2015}, abstract = {Instabilities of the interface between two thin liquid films under DC electroosmotic flow are investigated using linear stability analysis followed by an asymptotic analysis in the long-wave limit. The two-liquid system is bounded by two rigid plates which act as substrates. The Boltzmann charge distribution is considered for the two electrolyte solutions and gives rise to a potential distribution in these liquids. The effect of van der Waals interactions in these thin films is incorporated in the momentum equations through the disjoining pressure. Marginal stability and growth rate curves are plotted in order to identify the thresholds for the control parameters when instabilities set in. If the upper liquid is a dielectric, the applied electric field can have stabilizing or destabilizing effects depending on the viscosity ratio due to the competition between viscous and electric forces. For viscosity ratio equal to unity, the stability of the system gets disconnected from the electric parameters like interface zeta potential and electric double-layer thickness. As expected, disjoining pressure has a destabilizing effect, and capillary forces have stabilizing effect. The overall stability trend depends on the complex contest between all the above-mentioned parameters. The present study can be used to tune these parameters according to the stability requirement.}, language = {en} }