| 초록 |
Silica particle dispersions are important in many industrial areas such as paints, composites, ceramic and structural materials. Nowadays, among the tremendous applicability of silica suspension, it can be used as abrasive particles in silicon wafer polishing or chemical mechanical polishing in semiconductor fabrication. Generally, silica slurry for wafer polishing is composed of the aqueous colloidal silica and some additives such as polishing accelerator and bactericide. And the aqueous silica slurry should be stabilized by addition of stabilizing agents such as surfactants and polymeric substances to enhance the life-time of the polishing slurry. Therefore, it is of practical significance to investigate the rheological behavior and phase stability of the particle suspensions. Moreover, the preparation of monodisperse silica particles as a model system can offer experimental and theoretical advantages since they can serve as easy standard calibration materials for analytical equipment. In the present study, we prepared amorphous colloidal silica suspensions through the growth of commercial seeds such as colloidal silica or fumed silica with the addition of TEOS. And then we tried to seek the method for appropriate phase stabilization. Therefore, we focused on the stabilization of the prepared aqueous silica suspensions by a polymeric surfactant. The water-soluble PVA has been widely used for the stabilization or flocculation of solid silica particles in an aqueous medium. One of the generally accepted suggestions is that the hydroxyl group (-OH) of PVA gives a strong attraction onto a surface silanol group (Si-OH) or surface siloxane group (Si-O-Si) on the silica surface by forming the hydrogen bonding. And to do this, their rheological behavior was also investigated to probe the phase stability of sterically stabilized silica suspension.
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