Download or read book Orientation Dynamics and Microscope Imaging of Colloidal Suspensions written by Brian David Leahy and published by . This book was released on 2016 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micron-sized colloidal particles provide a unique window into the workings of statistical mechanics. These particles are large enough to be easily imaged with a microscope, allowing for detailed, mechanistic testing of statistical theories, yet small enough to still feel the effects of Brownian motion and thermal forces. Moreover, these thermal forces result in dynamics that are controlled by energy scales at room temperature and time scales on the order of seconds. In addition to allowing detailed control over a colloidal suspension, these accessible scales allow for the possibility of driving the suspension far from equilibrium and the exploration of non-equilibrium statistical mechanics. Much work has focused on the behavior of spherical colloidal particles, which lack an orientational degree of freedom and have simpler dynamics. However, many real suspensions are composed of particles with an orientational degree of freedom. In this thesis I explore the dynamics of dilute suspensions of nonspherical colloidal particles far from equilibrium. First, using an experiment I show that the rotational diffusivity of rodlike colloidal particles is enhanced under shear. Second, using a simplified theory I analytically solve for these dynamics far from equilibrium (in the limit of large Péclet numbers). The e diffusivity is enhanced at a rate proportional to the square of the particle's aspect ratio. Interestingly, this solution also provides insight into the oscillatory shear dynamics of these particles, and into the continuous and oscillatory shear rheology of these suspensions. Third, I use this solution to control the alignment and rheology of a suspension of particles. Finally, I close by improving the microscope's resolution by 10-100x through image analysis alone, without modifying the microscope itself. By improving the resolution we expect to be able to see new dynamics of colloidal particles at unprecedented scales.
Download or read book Colloidal Suspension Rheology written by Jan Mewis and published by Cambridge University Press. This book was released on 2012 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented in an accessible and introductory manner, this is the first book devoted to the comprehensive study of colloidal suspensions.
Download or read book Flow driven Orientation Dynamics in Two Classes of Fibre Suspensions written by Uldis Strautins and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Particle Shape on the Structure and Rheology of Colloidal Suspensions and Gels written by Ali Mohraz and published by . This book was released on 2004 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rheology Volume I written by Crispulo Gallegos and published by EOLSS Publications. This book was released on 2010-11-30 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rheology is a component of Encyclopedia of Chemical Sciences, Engineering and Technology Resources in the global Encyclopedia of Life Support Systems (EOLSS), which is an integrated compendium of twenty Encyclopedias. Rheology is the study of the flow of matter. It is classified as a physics discipline and focuses on substances that do not maintain a constant viscosity or state of flow. That can involve liquids, soft solids and solids that are under conditions that cause them to flow. It applies to substances which have a complex molecular structure, such as muds, sludges, suspensions, polymers and other glass formers, as well as many foods and additives, bodily fluids and other biological materials. The theme on Rheology focuses on five main areas, namely, basic concepts of rheology; rheometry; rheological materials, rheological processes and theoretical rheology. Of course, many of the chapters contain material from more than one general area. Rheology is an interdisciplinary subject which embraces many aspects of mathematics, physics, chemistry, engineering and biology. These two volumes are aimed at the following five major target audiences: University and College students Educators, Professional practitioners, Research personnel and Policy analysts, managers, and decision makers and NGOs.
Download or read book In situ Characterization Techniques for Nanomaterials written by Challa S.S.R. Kumar and published by Springer. This book was released on 2018-04-17 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seventh volume of a 40 volume series on nanoscience and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about In-situ Characterization Techniques for Nanomaterials. Modern applications and state-of-the-art techniques are covered and make this volume an essential reading for research scientists in academia and industry.
Download or read book Dynamics Of Active Colloids In Liquid Crystal Environment written by Mojtaba Rajabi and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamics of micrometer-scale active colloids in complex fluids is of great fundamental and application interest. In this dissertation, we study the dynamics of active colloids placed in an orientationally ordered liquid. We demonstrate that the liquid crystal (LC) environment allows extracting useful work from the random motion of microswimmers and ambient external field in the form of self-propulsion of colloids. We also show that the simplest microswimmer in a low Reynolds number regime in an LC is a sphere; in contrast with the complicated structures and modes necessary for swimming in isotropic fluids. We demonstrate that a water droplet containing a suspension of randomly swimming bacteria placed in a nematic LC environment propels itself unidirectionally. The droplets with a hyperbolic hedgehog (HH) point defect in their vicinity that are of polar symmetry propel themselves while the droplets with Saturn ring (SR) director configuration of quadrupolar symmetry do not propel. In HH droplets, the propulsion is driven by the activity of bacteria; the droplets with higher bacteria concentration move faster, while the droplets with no bacteria or immotile bacteria do not propel. The bacteria generate a chaotic flow inside the droplet that is transferred to the nematic through the interface. The polar director structure around the HH droplet rectifies this chaotic flow into the directional self-propulsion of the droplet. The mechanism of motion is rooted in the coupling of flow and the director orientation in the nematic. The flow that is transferred into the nematic faces different resistances from the director structure around the droplet while streaming toward the HH as compared to the opposite direction. Thus, the net displacement is in the direction with less resistance. We show that the responsiveness of the LC to external cues such as electric field and light provides the means to dynamically control the speed and trajectories of the active droplets. An in-plane electric field reorients the director through dielectric coupling and thus redirects the droplet. Also, a high electric field transforms the HH into a disclination ring and thus reduces the droplet speed. When the ring becomes an equatorial SR the droplet stops. A focused laser beam is used to control the droplet motility and polarity of motion. The laser locally melts the director around the droplet and reversibly transforms the SR to HH, thus controlling the droplet motility. The beam is focused on the desired side of the droplet and determines the direction of motion by creating HH there. LC environment can also be used to enable and control the transport of inanimate colloidal particles. Previously, liquid crystal-enabled electrophoresis of colloids has been explored in which the particle propels with a speed quadratically proportional to the applied electric field. In this work, we describe highly nonlinear electrophoresis in nematic in which the velocity is proportional to the fourth and sixth powers of the field. This is the highest nonlinear electrophoresis effect ever reported. The mechanism is attributed to the field-generated charges in LC which modify the space charge. Finally, the observation and recording of the dynamics of birefringence environments require complex microscopy techniques. We describe a novel microscopy based on a polychromatic polarizing module (PPM) to map the director orientation of LC with a high spatial and temporal resolution. The technique allows us to study the dynamics of active LCs.
Download or read book Statics and Dynamics of Colloidal Suspensions with Attractive Interactions written by Johan Bergenholtz and published by . This book was released on 1996 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of Complex Interconnected Systems Networks and Bioprocesses written by Arne T. Skjeltorp and published by Springer Science & Business Media. This book was released on 2006-12-22 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews the synergism between various fields of research that are confronted with networks, such as genetic and metabolic networks, social networks, the Internet and ecological systems. In many cases, the interacting networks manifest so-called emergent properties that are not possessed by any of the individual components. Knowledge gained from the study of complex non-biological systems can be applied to the intricate braided relationships that govern cellular functions.
Download or read book Optical Studies of Colloidal Crystals written by Ioannis Monovoukas and published by . This book was released on 1990 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structure and Dynamics in Ordered and Disordered Colloidal Suspensions written by Stephen James Nilsen and published by . This book was released on 1996 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theory and Applications of Colloidal Suspension Rheology written by Norman J. Wagner and published by Cambridge University Press. This book was released on 2021-04-15 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Essential text on the practical application and theory of colloidal suspension rheology, written by an international coalition of experts.
Download or read book Confined Flow of Attractive Colloidal Suspensions written by Rahul Pandey and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Attractive particulate fluids flowing through complex confined geometries are frequently used in technological applications. While the flow properties of hard-sphere suspensions in micro-scale geometries have been studied extensively, the effects of interparticle attractions and particle size dispersity on the confined flow properties of particulate suspensions are not well understood. We used confocal microscopy, particle tracking, and bulk rheology to study the confined structure, dynamics, and flow properties of colloid-polymer mixtures, which serve as simple models of attractive particulate suspensions. We employed poly(methyl-methacrylate) spheres that were suspended in a refractive-index and density- matched solvent, and induced a controlled short-range depletion attraction between particles by adding non-absorbing linear polystyrene. First, we investigated the effects of particle size dispersity on confinement-induced solidification of colloid-polymer mixtures. We formulated mixtures of polymer and bidispersed colloids with particle size ratio aS/aL ≈ 0.49 at a constant total volume fraction fT and measured the dynamics of the large particles as a function of the volume fraction of large particles. The dynamics of large particles became slower as the volume fraction of large particles r=fL/fT was decreased or the confinement thickness was decreased, indicating increasingly solid-like behavior. Second, we investigated the effects of variation in particle size dispersity r on the rheology and microstructure of mixtures of polymer and bidispersed colloids. Significant changes in rheology and microstructure were observed only at high volume fractions of large particles. By contrast, dense suspensions fT = 0.40 were strong gels at all concentration of large particles and exhibited only modest rheological and microstructural changes. Finally, we investigated the effects of variation in interparticle attractions on the microchannel flow of colloid-polymer mixtures. In suspensions with weak interparticle attractions, the number density of particles increased downstream in the channel due to shear-induced migration and consolidation by compression. In suspensions with stronger interparticle attractions, an interconnected network of particles suppressed these mechanisms and prevented the increase in density downstream. Together, our results indicate that the confined structure, dynamics, and flow properties of attractive colloidal suspensions can be controllably tuned from fluid-like to solid-like by varying the interparticle attractions and the particle size dispersity.
Download or read book Dynamics in Concentrated Colloidal Suspensions written by N. B. Simeonova and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Behavior of Concentrated Colloidal Suspensions by Stokesian Dynamics Simulation written by Thank Ngoc Phung and published by . This book was released on 1993 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic Resonance Microscopy written by Sarah L. Codd and published by John Wiley & Sons. This book was released on 2008-12-17 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook and ready reference covers materials science applications as well as microfluidic, biomedical and dental applications and the monitoring of physicochemical processes. It includes the latest in hardware, methodology and applications of spatially resolved magnetic resonance, such as portable imaging and single-sided spectroscopy. For materials scientists, spectroscopists, chemists, physicists, and medicinal chemists.
Download or read book Silicon Nanomaterials Sourcebook written by Klaus D. Sattler and published by CRC Press. This book was released on 2017-07-28 with total page 1133 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive tutorial guide to silicon nanomaterials spans from fundamental properties, growth mechanisms, and processing of nanosilicon to electronic device, energy conversion and storage, biomedical, and environmental applications. It also presents core knowledge with basic mathematical equations, tables, and graphs in order to provide the reader with the tools necessary to understand the latest technology developments. From low-dimensional structures, quantum dots, and nanowires to hybrid materials, arrays, networks, and biomedical applications, this Sourcebook is a complete resource for anyone working with this materials: Covers fundamental concepts, properties, methods, and practical applications. Focuses on one important type of silicon nanomaterial in every chapter. Discusses formation, properties, and applications for each material. Written in a tutorial style with basic equations and fundamentals included in an extended introduction. Highlights materials that show exceptional properties as well as strong prospects for future applications. Klaus D. Sattler is professor physics at the University of Hawaii, Honolulu, having earned his PhD at the Swiss Federal Institute of Technology (ETH) in Zurich. He was honored with the Walter Schottky Prize from the German Physical Society, and is the editor of the sister work also published by Taylor & Francis, Carbon Nanomaterials Sourcebook, as well as the acclaimed multi-volume Handbook of Nanophysics.
