Supplementary animation 1. In this experiment the dimensions of the mixer were w = 140 μm, h = 58 μm, le = 250 μm, and wg = 40 μm. Mixing experiments were conducted such that two channel inlets containing a buffer solution (TES) were joined at a T-juntion immediately upstream of the mixing electrodes, where one of these inlet streams also contains a fluorescent dye (rhodamine B). In these movies flow is moving from left to right, with a rhodamine/buffer flow rate ratio of 1:2, and an average flow velocity of 6 mm/s. A voltage potential of Δφ = 2.0 V is applied across the electrode gaps, with the bottom electrodes having a positive potential. This movie is taken approximately 2 mm downstream of the T-junction, after the first electrode cycle.

Supplementary animation 2. This movie corresponds to the same mixer as in Animation 1, with the same flow conditions. These images were taken approximately 6 mm downstream of the T-junction, after the third electrode cycle.

Supplementary animation 3. In this experiment the dimensions of the mixer were w = 140 μm, h = 58 μm, le = 250 μm, and wg = 40 μm. Mixing experiments were conducted such that two channel inlets containing a buffer solution (TES) were joined at a T-juntion immediately upstream of the mixing electrodes, where one of these inlet stream also contains 0.5 μm diameter fluorescent polymer microspheres (Duke Scientific). Flow is moving left to right, with a fluorescent particle/buffer flow rate ratio of 1:1, and an averge flow velocity of approximatley 1 mm/s. A voltage potential of Δφ = 2.0 V is applied across the electrode gaps, with the bottom electrodes having a positive potential. As seen in this movie, the negatively charged microspheres are attracted to the bottom electrode; however the helical flow profile between the electrode gaps may clearly be seen. Note: this animation is 33 MB and may take several minutes to load.