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Author Conrad, Jacinta Carmel
Title Mechanical response and dynamic arrest in colloidal glasses and gels
book jacket
Descript 151 p
Note Source: Dissertation Abstracts International, Volume: 66-04, Section: B, page: 2120
Adviser: David Weitz
Thesis (Ph.D.)--Harvard University, 2005
In this thesis, we study the relationship of dynamics to structure in colloidal suspensions near the nonequilibrium fluid-to-solid glass and gelation transitions, using microscopy, light scattering, and bulk rheology. In Chapter 1 we introduce and motivate the thesis
We study the microscopic behavior of colloidal glasses and supercooled fluids using confocal microscopy. In Chapter 2 we correlate local dynamics, characterized by the mean-squared displacement, to the local volume, characterized by the Voronoi volume, and find that these quantities are only weakly correlated. In Chapter 3 we approach the glass transition from a novel perspective by focusing on the elastic, solid-like behavior of the suspensions. We identify static particles in colloidal suspensions and find that these particles are spatially correlated and form extended clusters. We propose that these clusters are the origin of elasticity in colloidal supercooled fluids and glasses. In Chapter 4 we apply ideas from frustrated spin model systems and study the diffusion and spread of mobility in colloidal supercooled fluids and glasses
We then study the nonequilibrium phase behavior and phase transition for colloidal suspensions with long-range attractions. In Chapter 5 we show that the gelation of colloid-polymer mixtures can result from phase separation followed by a kinetic arrest of the dense phase, and identify the signatures of this transition in microscopy and light scattering. In Chapter 6 we study the rheological behavior of gels formed via phase separation and arrest. In Chapter 7 we report the observation of fluid-cluster phases in both the absence and presence of charge. In Chapter 8 we present a broad study of the phase behavior of attractive colloidal suspensions at intermediate volume fractions, &phis; = 0.15--0.35, using microscopy, static and dynamic light scattering, and bulk rheology; we show that arrest results from the interplay of binodal and spinodal phase separations with an attractive glass arrest
School code: 0084
Host Item Dissertation Abstracts International 66-04B
Subject Physics, Condensed Matter
0611
Alt Author Harvard University
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