PMC

(a) Fluid segment sliced from microchannel for simulation. (b) 3-D simulation domain.

Schematics of Dry Etching, Electroplating and Molding (DEEMO) fabrication process for microchannel with large-area of black silicon nanostructures and smooth microchannel.

Simulated electric field lines for (a) smooth microchannel and (b) microchannel with black silicon nanostructures, for 1 mM of NaHCO₃.

Simulated EOF velocity profile for (a) smooth microchannel and (b) microchannel with black silicon nanostructures, for 1 mM of NaHCO₃.

Experimental and numerical average EOF velocities of 1 mM NaHCO₃ for microchannel with black silicon nanostructures, in comparison to smooth microchannel.

(a) Experimental setup for current monitoring technique. (b) Current-time curve for 0.95 mM NaHCO₃ displaced 1 mM NaHCO₃ in smooth microchannel.

(a) 3-D exploded view diagram of micro-/nanofluidic device. (b) Schematic of microchannel designs with/without black silicon nanostructures. (c) Atomic force microscope (AFM) image of black silicon nanostructures on the bottom wall of the microchannel.

Variation of numerical average EOF velocity for 1 mM NaHCO₃ with (a) height h where diameter d = 270 nm and spatial distance s = 350 nm, and (b) d where h = 175 nm and s = 350 nm.

(a) Displacement times, (b) electroosmotic flow (EOF) velocities and magnitude of effective zeta potentials for 1 mM, 5 mM and 10 mM of NaHCO₃ for microchannel with black silicon nanostructures, in comparison to smooth microchannel.