Video microscopy of colloidal suspensions and colloidal crystals

Habdas, Piotr; Weeks, Eric R.

doi:10.1016/s1359-0294(02)00049-3

Cited by 72 publications

(56 citation statements)

References 56 publications

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“…At each temperature, 5 min of video were recorded in bright-field microscopy, 2-4 min of video were recorded for each layer in confocal microscopy, and 1-10 3D confocal scans of the static structure were taken. Video rates were 30 frames/sec in bright-field microscopy and 7.5 frames/sec in confocal microscopy [32]. The particle positions in each frame were obtained using standard 2D and 3D image analysis algorithms [33].…”

Section: Methodsmentioning

confidence: 99%

Melting of multilayer colloidal crystals confined between two walls

et al. 2011

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Video microscopy is employed to study the melting behaviors of multilayer colloidal crystals composed of diameter-tunable microgel spheres confined between two walls. We systematically explore film thickness effects on the melting process and on the phase behaviors of single crystal and polycrystalline films. Thick films (>4 layers) are observed to melt heterogeneously, while thin films (≤4 layers) melt homogeneously, even for polycrystalline films. Grain-boundary melting dominates other types of melting processes in polycrystalline films thicker than 12 layers. The heterogeneous melting from dislocations is found to coexist with grain-boundary melting in films between 5- and 12-layers. In dislocation melting, liquid nucleates at dislocations and forms lakelike domains embedded in the larger crystalline matrix; the "lakes" are observed to diffuse, interact, merge with each other, and eventually merge with large strips of liquid melted from grain boundaries. Thin film melting is qualitatively different: thin films homogeneously melt by generating many small defects which need not nucleate at grain boundaries or dislocations. For three- and four-layer thin films, different layers are observed to have the same melting point, but surface layers melt faster than bulk layers. Within our resolution, two- to four-layer films appear to melt in one step, while monolayers melt in two steps with an intermediate hexatic phase.

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Section: Methodsmentioning

confidence: 99%

Melting of multilayer colloidal crystals confined between two walls

et al. 2011

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“…In this section, we will review recent experiments that probe dynamical heterogeneity in a variety of systems, ranging from model hard sphere suspensions to more complicated glassy samples, such as colloidal gels and concentrated surfactant phases. Most experiments are performed using time-resolved confocal scanning microscopy [20] or recently introduced light scattering methods that allow temporal heterogeneities to be measured [33], as it will be discussed in the following subsections.…”

Section: Dynamical Heterogeneitymentioning

confidence: 99%

“…Once the particle trajectories are known, a wide range of statistical quantities can be calculated in order to detect, characterize, and quantify dynamical heterogeneity. Direct comparison with simulation work is possible, making optical microscopy a powerful experimental technique for investigating slow dynamics in glassy soft materials (for a recent review of video microscopy applied to colloidal suspensions, see reference [20]). …”

Section: Optical Microscopy Experimentsmentioning

confidence: 99%

Slow dynamics in glassy soft matter

Cipelletti¹,

Ramos

2005

J. Phys.: Condens. Matter

364

410

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Abstract.Measuring, characterizing and modelling the slow dynamics of glassy soft matter is a great challenge, with an impact that ranges from industrial applications to fundamental issues in modern statistical physics, such as the glass transition and the description of out-of-equilibrium systems. Although our understanding of these phenomena is still far from complete, recent simulations and novel theoretical approaches and experimental methods have shed new light on the dynamics of soft glassy materials. In this paper, we review the work of the last few years, with an emphasis on experiments in four distinct and yet related areas: the existence of two different glass states (attractive and repulsive), the dynamics of systems very far from equilibrium, the effect of an external perturbation on glassy materials, and dynamical heterogeneity.

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“…Confocal microscopy of colloidal suspensions in the absence of flow has been reviewed recently [19,[29][30][31], and we refer the reader to these reviews for details and references. Here, we simply note that this methodology gives direct access to local processes, such as crystal nucleation [32] and dynamic heterogeneities in hard-sphere suspensions near the glass transition [33,34].…”

Section: Imaging Colloidal Suspensionsmentioning

confidence: 99%

Quantitative imaging of colloidal flows

Besseling

Isa

Weeks

et al. 2009

Advances in Colloid and Interface Science

131

180

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We present recent advances in the instrumentation and analysis methods for quantitative imaging of concentrated colloidal suspensions under flow. After a brief review of colloidal imaging, we describe various flow geometries for two and three-dimensional (3D) imaging, including a 'confocal rheoscope'. This latter combination of a confocal microscope and a rheometer permits simultaneous characterization of rheological response and 3D microstructural imaging. The main part of the paper discusses in detail how to identify and track particles from confocal images taken during flow. After analyzing the performance of the most commonly used colloid tracking algorithm by Crocker and Grier extended to flowing systems, we propose two new algorithms for reliable particle tracking in non-uniform flows to the level of accuracy already available for quiescent systems. We illustrate the methods by applying it to data collected from colloidal flows in three different geometries (channel flow, parallel plate shear and cone plate rheometry).

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Video microscopy of colloidal suspensions and colloidal crystals

Cited by 72 publications

References 56 publications

Melting of multilayer colloidal crystals confined between two walls

Melting of multilayer colloidal crystals confined between two walls

Slow dynamics in glassy soft matter

Quantitative imaging of colloidal flows

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