Authors: A. Oprisan, S.A. Oprisan, A. Teklu
Affilation: College of Charleston, United States
Pages: 71 - 74
Keywords: colloidal suspension, nanoparticle, free diffusion, shadowgraph method
Two experiments were performed using shadowgraph visualization technique in order to study the dynamics of concentration fluctuations. Our experimental setup includes an objective attached to the CCD camera to increase the field of view. Using two colloidal suspensions, one with gold and the other with silica colloid, we extracted both the structure factors and the correlation time during the intermediate to late stages of concentration fluctuations during a free diffusion experiment. The temporal evolution of fluctuations is qualitatively investigated using recursive plots and spatial-temporal sections of fluctuating images. Our experiment reveals significant differences between concentration fluctuations induced in silica and gold colloids. The difference is explained not only in terms of the particle size but due to the possible plasmonic interaction between gold nanoparticle and the incident light.