Synthesis and Characterization of Monodisperse Colloidal Silica with Tailored Optical and Surface Properties Katie Pickrahn Mentor: Ali Mohraz Colloids are solid particles with at least one characteristic dimension between a few nanometers and a few micrometers. Silica is one material that has repeatedly been used to create colloidal particles, owing to the ease by which large quantities of silica particles of the same size may be produced. The goal of this project is to systematically synthesize monodisperse, core-shell colloidal silica with tailored surface chemistries and optical properties. The core-shell architecture consists of a fluorescent core surrounded by a nonfluorescent layer, allowing for the imaging of these particles using confocal laser scanning microscopy. These particles are used as model materials for fundamental research in colloid science and soft matter physics. The results of digital image processing of the core-shell particles and particles that are fluorescent throughout are discussed. Colloidal silica may also be used as scattering agents in light guides, requiring dispersion of the particles in an organic monomer solution. The effects of particle surface chemistry on suspension stability in an organic solvent are discussed. By controlling the size and surface chemistry of colloidal silica and understanding the effects of the coreshell architecture on digital imaging, we can better tailor the production of particles that enhance research in colloid science.