(186aw) Structure of Colloidal Gels during Microchannel Flow
- Conference: AIChE Annual Meeting
- Year: 2008
- Proceeding: 2008 Annual Meeting
- Group: Engineering Sciences and Fundamentals
- Session:
- Time: Monday, November 17, 2008 - 6:00pm-8:30pm
We investigate the flow behavior of colloidal gels in microchannels using confocal microscopy. We study two model systems: one in which silica microspheres are flocculated via polyelectrolyte additions, and the other composed of hydrophobically modified silica microspheres. Both of these attractive colloid suspensions exhibit shear-thinning behavior with a finite yield stress. Under shear flow, the bulk flow profiles change from plug-like at low pressures to fluid-like at high pressures. We vary the applied pressure, the microchannel geometry, and the colloid volume fraction, and systematically study the structure of each model system during flow.