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作者 Vesaratchanon, Jan Sudaporn
書名 Sedimentation of colloidal dispersions: Effects of collective interactions and particle charge
國際標準書號 9780549094296
book jacket
說明 200 p
附註 Source: Dissertation Abstracts International, Volume: 68-06, Section: B, page: 3974
Adviser: Darsh T. Wasan
Thesis (Ph.D.)--Illinois Institute of Technology, 2007
We investigated the role of collective interactions in the sedimentation of nanocolloidal dispersions using non-destructive Kossel diffraction technique. Settling concentration profile was obtained during sedimentation. It was found that at the particle concentration higher than 6.5 vol%, the collective interactions due to self-depletion of particles play a dominant role. We developed a model based on particle dynamics simulation accounting for collective hard-sphere interaction in concentrated suspensions to predict the sedimentation rate. Good agreement was found between the experimental observations and model predictions
The role of depletion and oscillatory structural forces were studied in the sedimentation experiment of binary suspensions containing microspheres in the presence of smaller nanoparticles. The particle concentration profile and packing structure were obtained using Kossel diffraction technique based on the theory of back-light scattering. The effective interaction between large particles in the presence of small particles was found to be oscillatory decay which is the combination of depletion and repulsive structural forces. Theoretical model based on particle dynamics method accounting for collective colloidal particle interactions was developed to explain experimental observations. By introducing the effective interaction between the large particles in the presence of small particles, a good agreement was found between the sedimentation velocity of the experiments and model predictions
The collective interaction between similarly-charged colloidal particles was investigated using Monte Carlo simulation and a Beresford-Smith potential. Based on the potential of mean force, as the particle concentration and/or number of charge increase, the effective interaction between charged particles becomes oscillatory with an attractive interaction generated as a result of particle collective effects. A transition from colloidal disordered to ordered structure is observed. The role of particle collective interactions in charged colloidal dispersion in the sedimentation velocity were considered using particle dynamic simulation based on effective potential of mean force between charged colloids. The particle charge plays a significant role as a result of colloidal ordered structure. It was found that the sedimentation process remains stable at relatively high particle concentration (about 20 vol%)
School code: 0091
Host Item Dissertation Abstracts International 68-06B
主題 Engineering, Chemical
Alt Author Illinois Institute of Technology
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