In this masters thesis, we explore the use of cross-correlation dynamic microscopy to measure the electrophoretic mobility of colloidal particles in aqueous suspensions. Cross-correlation dynamic microscopy, a novel technique, based on Fourier microscopy, enables us to obtain results equivalent to Dynamic Light Scattering measurements made in the far-field with a simple laboratory microscope in the near-field. By using two cameras instead of one we can achieve higher temporal resolution and study fast dynamics in the system. We preform measurements of eletrophoretic mobility in a microchannel in the presence of an alternating external electric field. By choosing an appropriate frequency of the external electric field, we can directly obtain the value of the electrophoretic mobility of colloidal particles if the measurements are done in the middle of the channel.
|