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Lewis, Jennifer A. Tohver, Valeria 2015-09-25T20:52:34Z 2015-09-25T20:52:34Z 10000-01-01 2001 2001 The phase behavior, structure, and properties of binary mixtures of negligibly charged colloidal microspheres were studied for two size ratios of 95 and 197 at pH = 1.5. In the absence of nanoparticle additions, the system spontaneously assembled into a colloidal gel whose strength increased with microsphere volume fraction. Between a lower and upper critical nanoparticle volume fraction, such binary mixtures formed a stable fluid phase due to nanoparticle haloing. In this concentration regime, colloidal microsphere crystals could be assembled under gravity-driven sedimentation. Confocal microscopy revealed that such crystals exhibited a center-to-center microsphere separation distance of 2 amusphere, where amusphere is the microsphere radius. Above the upper critical nanoparticle volume fraction, depletion flocculation induced by the presence of highly charged nanoparticles in solution led to the reformation of a colloidal gel phase. The structure and strength of the colloidal gel phases observed below and above the homogeneous fluid phase could be tailored by varying the respective colloidal microsphere and nanoparticle volume fractions, as evidenced by optical microscopy, sedimentation and rheological measurements. Made available in DSpace on 2015-09-25T20:52:34Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3023216.pdf: 5351653 bytes, checksum: c3991ebf56eada3cffd9d5fcd2ccc5b0 (MD5) Previous issue date: 2001 Embargo set by: Seth Robbins for item 83988 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 121 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2001. http://hdl.handle.net/2142/82707 (MiAaPQ)AAI3023216 eng Engineering, Chemical Phase Behavior, Structure, and Properties of Colloidal Microsphere-Nanoparticle Mixtures text Materials Science and Engineering Materials Science and Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.