Study of mixing enhanced by a magnetic field in a microfluidic channel

Mixing in a microfluidic environment is challenging due to the laminarity of flow. The idea of the present study is to apply a magnetic force to a stratified channel flow. Due to the different magnetic susceptibilities of the liquid layers, mixing might be triggered. The magnetic gradient force is generated simply by the application of permanent magnets. Fig. 1 shows the channel setup with two entries and two outflows. The upper entry is fed with water, whereas the lower entry is fed with 0.1 M HoCl3 solution. On top of the front part, the magnets are applied. Different flow rates and magnet configurations were studied. The degree of mixing is measured by determining the concentration of HoCl3 in the upper outlet by a spectrophotometer measuring the absorbance at a specific wavelength. Additional Micro-PIV measurements are performed to resolve the related flow pattern in detail. Numerical simulations are performed to complement the investigation.