Microrheology: Video Particle Tracking of Microspheres
I researched on the microrheology of colloidal mixture with Dr. Pietro Cicuta at the Cavendish Lab of the University of Cambridge from July to August 2008. I constructed a sol-gel phase diagram by mixing colloidal silica (Ludox Hs?30), surfactant (CTAB), and NaCl in various ratios. Furthermore, I observed and analyzed the properties of the mixture by measuring the mean square deviation (MSD) of embedded microspheres (i.e., video particle tracking, see Fig. 1). In particular, I scrutinized the time (elapsed time after mixing to be precise) dependency and ratio dependency of MSD. In this research, I enhanced the existing particle tracking code by introducing a well-known background noise reduction method in astronomy with Timo Stein: dividing each initial noise-prone image by the background noise image (Fig. 2). Also, I devised a technique that increases the video recording frame rate on limited computing capacity.
Figure 1: video particle tracking of embedded microspheres (1 ?m) in a colloidal mixture. The mean square deviation value can be readily calculated from the trajectories of the particles.
Figure 2: improved images can be obtained by dividing pixel by pixel with the background noise image.
