Download or read book Measured Capillary Forces on Spheres at Liquid Interfaces and the Mechanics of Interfacial Particulate Assemblies written by Wei He and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle-laden interfaces have promising potentials in many fields because the particulate nature can endow the surface with physical properties that are not readily obtained from molecular-scale surfactants. In this dissertation, we first focus on measuring capillary forces on particles at fluid interfaces in order to assess the key parameters that yield effective stabilizing particles. In experiment, the force and the displacement of a millimeter-scale particle passing through a liquid interface were recorded. We find that the peak force needed to detach a particle from an interface crowded with other particles is consistently smaller than the force at a clean interface. By ruling out other possibilities, we attribute the force reduction to the perturbation of interface shape due to the constraints imposed by free particles. Then we study the mechanics of particulate assemblies by measuring the force response under a normal indentation. We find that there exist two linear regions with different slopes. The small-slope regime starts at the beginning and persists over a range of indentations much less than capillary length. Once the system entered the higher plateau region, it has the same stiffness as a pure liquid interface. Further, from top-view images, we showed that, as long as the indenter was larger than the size of a single particle, the azimuthal compression can be relaxed through the in-plane rearrangement of particles. These features are independent of the difference in fluid mass densities, the radius of the indenter and the species of particles. Although the presence of floating particles at an interface does not change its capillary nature under a wide range of poking depth, we show that the existence of the particle raft makes the original interface tougher in terms of both the maximum force it can sustain and the largest indentation an indenter can reach. These results provide an important step toward understanding the mechanics of particulate assemblies at interfaces. Finally, we study the formation of organic 2D material in aqueous media for the purpose of potential applications in passivating objects in suspension. We optimized the conditions for the self-assembly of bola-amphiphilic molecules, and directly observed 2D sheets in optical microscope under dark-field illumination. We find that stacking is not preferred by sheets because of the likely electrostatic repulsion. Our method provides an effective way to better understand the properties of those sheets.
Download or read book Surface and Interfacial Forces written by Hans-Jürgen Butt and published by John Wiley & Sons. This book was released on 2018-06-05 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: A general introduction to surface and interfacial forces, perfectly combining theoretical concepts, experimental techniques and practical applications. In this completely updated edition all the chapters have been thoroughly revised and extended to cover new developments and approaches with around 15% new content. A large part of the book is devoted to surface forces between solid surfaces in liquid media, and while a basic knowledge of colloid and interface science is helpful, it is not essential since all important concepts are explained and the theoretical concepts can be understood with an intermediate knowledge of mathematics. A number of exercises with solutions and the end-of-chapter summaries of the most important equations, facts and phenomena serve as additional tools to strengthen the acquired knowledge and allow for self-study. The result is a readily accessible text that helps to foster an understanding of the intricacies of this highly relevant topic.
Download or read book Particles at Fluid Interfaces and Membranes written by P. Kralchevsky and published by Elsevier. This book was released on 2001-01-22 with total page 669 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the small world of micrometer to nanometer scale many natural and industrial processes include attachment of colloid particles (solid spheres, liquid droplets, gas bubbles or protein macromolecules) to fluid interfaces and their confinement in liquid films. This may lead to the appearance of lateral interactions between particles at interfaces, or between inclusions in phospholipid membranes, followed eventually by the formation of two-dimensional ordered arrays. The book is devoted to the description of such processes, their consecutive stages, and to the investigation of the underlying physico-chemical mechanisms. The first six chapters give a concise but informative introduction to the basic knowledge in surface and colloid science, which includes both traditional concepts and some recent results. Chapters 1 and 2 are devoted to the basic theory of capillarity, kinetics of surfactant adsorption, shapes of axisymmetric fluid interfaces, contact angles and line tension. Chapters 3 and 4 present a generalization of the theory of capillarity to the case, in which the variation of the interfacial (membrane) curvature contributes to the total energy of the system. The generalized Laplace equation is applied to determine the configurations of free and adherent biological cells. Chapters 5 and 6 are focused on the role of thin liquid films and hydrodynamic factors in the attachment of solid and fluid particles to an interface. Surface forces of various physical nature are presented and their relative importance is discussed. Hydrodynamic interactions of a colloidal particle with an interface (or another particle) are also considered.Chapters 7 to 10 are devoted to the theoretical foundation of various kinds of capillary forces. When two particles are attached to the same interface (membrane), capillary interactions, mediated by the interface or membrane, appear between them. Two major kinds of capillary interactions are described: (i) capillary immersion force related to the surface wettability (Chapter 7), (ii) capillary flotation force originating from interfacial deformations due to particle weight (Chapter 8). Special attention is paid to the theory of capillary immersion forces between particles entrapped in spherical liquid films (Chapter 9). A generalization of the theory of immersion forces allows one to describe membrane-mediated interactions between protein inclusions into a lipid bilayer (Chapter 10).Chapter 11 is devoted to the theory of the capillary bridges and the capillary-bridge forces, whose importance has been recognized in phenomena like consolidation of granules and soils, wetting of powders, capillary condensation, long-range hydrophobic attraction, etc. The nucleation of capillary bridges is also examined.Chapter 12 considers solid particles, which have an irregular wetting perimeter upon attachment to a fluid interface. The undulated contact line induces interfacial deformations, which engender a special lateral capillary force between the particles. The latter contributes to the dilatational and shear elastic moduli of particulate adsorption monolayers.Chapter 13 describes how lateral capillary forces, facilitated by convective flows and some specific and non-specific interactions, can lead to the aggregation and ordering of various particles at fluid interfaces or in thin liquid films. Recent results on fabricating two-dimensional (2D) arrays from micrometer and sub-micrometer latex particles, as well as 2D crystals from proteins and protein complexes, are reviewed. Chapter 14 presents applied aspects of the particle-surface interaction in antifoaming and defoaming. The mechanisms of antifoaming action involve as a necessary step the entering of an antifoam particle at the air-water interface. The considered mechanisms indicate the factors for control of foaminess.
Download or read book Colloidal Particles at Liquid Interfaces written by Bernard P. Binks and published by Cambridge University Press. This book was released on 2006-08-17 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: The understanding of how small solid particles operate at liquid interfaces is minimal. This book brings together the topics actively being investigated, with contributions from experts in the field. It will be of interest to researchers in chemistry, physics, chemical engineering, pharmacy, food science and materials science.
Download or read book Surface and Interfacial Tension written by Stanley Hartland and published by CRC Press. This book was released on 2004-03-11 with total page 773 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edited volume offers complete coverage of the latest theoretical, experimental, and computer-based data as summarized by leading international researchers. It promotes full understanding of the physical phenomena and mechanisms at work in surface and interfacial tensions and gradients, their direct impact on interface shape and movement, and t
Download or read book CONTACT ANGLES AND CONTACT LINES AROUND PARTICLES AT ISOTROPIC AND ANISOTROPIC LIQUID INTERFACES written by Nesrin Senbil and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid interfaces, capillarity and self-assembly of particles at interfaces are important in nature and technology. When a particle is adsorbed to a liquid interface, the contact line of the particle with the liquid interface and the associated contact angle are the crucial parameters that drive assembly of the particles. We looked at how the shape of the liquid interface and the shape of the particle affect the contact angle and the shape of the contact line. We used millimeter-sized PDMS-coated glass spheres and measured the contact angles at isotropic (planar) and anisotropic interfaces (saddle and cylindrical in shape). Anisotropy of the liquid interface is defined by the deviatoric curvature D0>. We look at the apparent advancing and receding contact angles (qA, qR) separately. We found that as the anisotropy of the interface, D0, increased from 0 to 0.22mm-1, the apparent receding angle, qR, decreased from 101° to 80°. Over the same experiments, qA remained fixed at 109°. As D0 increases, we also find that the contact line around the sphere deforms. We make analogy to electrostatics to describe the shape of the contact line in terms of multipole moments. We measured that as D0 increased, the magnitude of the quadrupolar moment (z2) increased and qR decreased. Magnitudes of z2 measured in our experiments agree with previous predictions when capillary force is zero. We also measure the z2with applied capillary force. However, there is no theory to compare it. To our knowledge, this is the first time that quadrupolar deformation of contact line around a particle is observed and measured directly. Moreover, we showed that advancing and receding contact angles of anisotropic shaped solids, such as cylinders, differ at a planar interfaces, which we attribute to the deformation of the contact line. Our results bring a new perspective to contact angles, showing that the advancing and receding angles depend on liquid-interface geometry, which had not previously been appreciated. Thus, our results are broadly important for capillarity and self-assembly related problems.
Download or read book Mathematical Theory Of Liquid Interfaces Liquid Layers Capillary Interfaces Floating Drops And Particles written by Erich Miersemann and published by World Scientific. This book was released on 2020-03-16 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book lays a unique and straightforward mathematical foundation on the aspects of liquid layers, capillary interfaces, floating drops and particles. For the first time, these topics are studied in a joint framework. Readers will acquire deeper comprehension and gain results. Practical interest are presented, making it beneficial to engineers and physicists as well as mathematicians.The text takes an insight-oriented approach that gives it immediacy and flexibility. It contains 70 problems where some are exercises, while others are open problems. It is also illustrated with 95 figures and photographs for further understanding.
Download or read book Particles Confined by Fluid Interfaces written by Paul Y. Kim and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Small solid particles, confined in two-dimensions by fluid interfaces, were studied by a variety of experimental methods to understand particle motion, menisci shapes near interface-supported particles, and capillary interactions among such particles. Unwanted evaporation was circumvented by adopting non-volatile ionic liquids to create the fluid interfaces. A related application, employment of ionic liquids to float cryo-microtomed polymer sections, was also developed. The Brownian motions of nanospheres and nanorods in free-standing ionic liquid films were visualized in situ by high resolution scanning electron microscopy, which images features almost 100x smaller than possible in an optical microscope. For suspensions that are dilute and films that are thick compared to the particle diameter, the translational and rotational diffusion coefficients determined by single-particle tracking agreed with existing theoretical predictions. In thinner films, a striking and unexpected dynamical pairing of nanospheres was observed, suggesting a balance of capillary and hydrodynamic interactions. Nanospheres at high concentration displayed subdiffusive caged motion and hexagonal-lattice crystallization. Concentrated nanorods in the thinner films transiently assembled into finite stacks but did not achieve high tetratic liquid crystalline order, perhaps because of spherical impurities. A small spherical microparticles on a cylindrically curved liquid interface, to maintain constant contact angle about its wetted periphery, locally induces a quadrupolar interface deformation. Measured by optical profilometry, this deformation was compared to a recent theoretical expression, and good agreement was noted. The interface quadrupoles lead to particle capillary interactions in analogy to a 2d electrostatic quadrupoles, and as one consequence, spheres on a cylindrical interface assemble tetragonally. The assembly was monitored in the optical microscope, with particles driven to assembly as predicted, into a tetragonal lattice aligned with the underlying cylindrical axis. Lastly, ionic liquids and their mixtures with low molecular weight solvents were applied as flotation liquids for cryo-ultramicrotomy. With control of glass transition temperature and liquid viscosity, flat and ultra-thin sections were reliably floated onto transmission electron microscopy grids at cryogenic temperature. Compared to established flotation media for soft polymer systems, the required time and skill are significantly reduced, and the operator was not exposed to noxious fumes.
Download or read book Anisotropic Particle Assemblies written by Ning Wu and published by Elsevier. This book was released on 2018-07-12 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anisotropic Particle Assemblies: Synthesis, Assembly, Modeling, and Applications covers the synthesis, assembly, modeling, and applications of various types of anisotropic particles. Topics such as chemical synthesis and scalable fabrication of colloidal molecules, molecular mimetic self-assembly, directed assembly under external fields, theoretical and numerical multi-scale modeling, anisotropic materials with novel interfacial properties, and the applications of these topics in renewable energy, intelligent micro-machines, and biomedical fields are discussed in depth. Contributors to this book are internationally known experts who have been actively studying each of these subfields for many years.This book is an invaluable reference for researchers and chemical engineers who are working at the intersection of physics, chemistry, chemical engineering, and materials science and engineering. It educates students, trains the next generation of researchers, and stimulates continuous development in this rapidly emerging area for new materials and innovative technologies. - Provides comprehensive coverage on new developments in anisotropic particles - Features chapters written by emerging and leading experts in each of the subfields - Contains information that will appeal to a broad spectrum of professionals, including but not limited to chemical engineers, chemists, physicists, and materials scientists and engineers - Serves as both a reference book for researchers and a textbook for graduate students
Download or read book Selected Papers from 2017 International Conference on Micro Nanomachines written by Jianguo Guan and published by MDPI. This book was released on 2018-08-09 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Selected Papers from 2017 International Conference on Micro/Nanomachines" that was published in Micromachines
Download or read book Interfacial Phenomena written by Clarence A. Miller and published by CRC Press. This book was released on 2007-10-08 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the publication of the first edition of Interfacial Phenomena, the interest in interfaces and surfactants has multiplied, along with their applications. Experimental and theoretical advances have provided scientists with greater insight into the structure, properties, and behavior of surfactant and colloid systems. Emphasizing equil
Download or read book Interfacial Phenomena written by J.T. Davies and published by Academic Press. This book was released on 2012-12-02 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interfacial Phenomena examines the fundamental properties of various liquid interfaces. This book discusses the physics of surfaces; electrostatic and electrokinetic phenomena; and adsorption at liquid interfaces. The properties of monolayers; reactions at liquid surfaces; diffusion through interfaces; and disperse systems and adhesion are also deliberated. Other topics include the vapor pressures over curved surfaces; electrical capacity of the double layer; applications of electrophoresis; and thermodynamics of adsorption and desorption. The experimental methods of spreading films at the oil-water interface; penetration into monolayers; experiments on dynamic systems; and spontaneous emulsification are likewise covered in this text. This book is beneficial to chemical engineers and students concerned with interfacial phenomena.
Download or read book Flowing Matter written by Federico Toschi and published by Springer Nature. This book was released on 2019-09-25 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book, published in the Soft and Biological Matter series, presents an introduction to selected research topics in the broad field of flowing matter, including the dynamics of fluids with a complex internal structure -from nematic fluids to soft glasses- as well as active matter and turbulent phenomena. Flowing matter is a subject at the crossroads between physics, mathematics, chemistry, engineering, biology and earth sciences, and relies on a multidisciplinary approach to describe the emergence of the macroscopic behaviours in a system from the coordinated dynamics of its microscopic constituents. Depending on the microscopic interactions, an assembly of molecules or of mesoscopic particles can flow like a simple Newtonian fluid, deform elastically like a solid or behave in a complex manner. When the internal constituents are active, as for biological entities, one generally observes complex large-scale collective motions. Phenomenology is further complicated by the invariable tendency of fluids to display chaos at the large scales or when stirred strongly enough. This volume presents several research topics that address these phenomena encompassing the traditional micro-, meso-, and macro-scales descriptions, and contributes to our understanding of the fundamentals of flowing matter. This book is the legacy of the COST Action MP1305 “Flowing Matter”.
Download or read book Bijels written by Paul S Clegg and published by Royal Society of Chemistry. This book was released on 2020-03-27 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bicontinuous interfacially jammed emulsion gels, now commonly termed 'bijels', are a class of soft materials, in which interpenetrating, continuous domains of two immiscible fluids are maintained in a rigid arrangement by a jammed layer of colloidal particles at their interface. Such gels have unusual material properties that promise exciting applications across diverse fields from energy materials and catalysis, to food science. This is the first book on the subject and provides the reader with a fundamental introduction. Edited by a recognised authority on bijels, the reader will learn about the bijel and its formation. Bringing together current understanding, this book aims to bring the potential application of bijels to diverse materials challenges closer to fruition. This is a must-have resource for anyone working in soft matter and applied fields.
Download or read book Evaporative Self assembly of Ordered Complex Structures written by Zhiqun Lin and published by World Scientific. This book was released on 2012 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of spontaneous self-assembly, as a lithographic tool and as an external field-free means to construct well-ordered and intriguing patterns, has received much attention. This book offers a spectrum of experimental and theoretical advances in evaporative self-assembly techniques.
Download or read book Fluid Interfaces written by Eduardo Guzmán and published by MDPI. This book was released on 2021-03-02 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid interfaces are promising candidates for confining different types of materials, e.g., polymers, surfactants, colloids, and even small molecules, to be used in designing new functional materials with reduced dimensionality. The development of such materials requires a deepening of the physicochemical bases underlying the formation of layers at fluid interfaces as well as on the characterization of their structures and properties. This is of particular importance because the constraints associated with the assembly of materials at the interface lead to the emergence of equilibrium and features of dynamics in the interfacial systems, which are far removed from those conventionally found in traditional materials. This Special Issue is devoted to studies on the fundamental and applied aspects of fluid interfaces, and attempts to provide a comprehensive perspective on the current status of the research field.
Download or read book Particle Deposition and Aggregation written by M. Elimelech and published by Elsevier. This book was released on 1998-08-07 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deposition and aggregation of small solid particles are encountered in many natural and industrial environments. Whether it be deposition of particles onto a surface immersed in a liquid suspension or aggregateion of individual particles, these processes are of enotmous significance. They are vital to the manufacture of magnetic tape, purification of water using packed bed filters, selective capture of solids, cells and macromolecular species, and many other applications. This book presents a unified approach to the measurement, modelling and simulation of these processes, bringing together the disciplines of colliod and surface chemistry, hydrodynamics, and experimental and computational methods. It will be required reading for graduates working in process and environmental engineering, postgraduates involved in industrial R & D and for all scientists wishing to gain a more detailed and realistic understanding of process conditions in these areas.
