AC electroosmotic flow of Maxwell fluid in a pH-regulated parallel-plate silica nanochannel

The surface charge property plays a crucial role in the electrokinetic flow in silica nanochannel in which the surface charge is generated by surface chemical reaction and is dependent on the solution pH. In nanofluidic devices, many of the fluids belong to the viscoelastic fluid class. In this work, we develop theoretical analysis for the effects of the solution pH, background salt concentration, and electric field frequency on an alternating current (AC) electroosmotic flow (EOF) of Maxwell fluid. The results show that the velocity amplitude of AC EOF of Maxwell fluid decreases with the background salt concentration and increases with the relaxation time and the deviation of the solution pH from the isoelectric point (pH = 3.05). The velocity amplitude of Maxwell fluid is greater than that of Newtonian fluid. In particular, the velocity amplitude of Maxwell fluid increases with the electric field frequency, whereas the velocity amplitude of Newtonian fluid remains unaffected by the electric field frequency.