Emulsion Formation and Stability

Emulsion Formation and Stability PDF

Author: Tharwat F. Tadros

Publisher: John Wiley & Sons

Published: 2013-06-04

Total Pages: 283

ISBN-13: 3527647961

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The importance of emulsification techniques, their use in the production of nanoparticles for biomedical applications as well as application of rheological techniques for studying the interaction between the emulsion droplets is gathered in this reference work. Written by some of the top scientists within their respective fields, this book covers such topics as emulsions, nano-emulsions, nano-dispersions and novel techniques for their investigation. It also considers the fundamental approach in areas such as controlled release, drug delivery and various applications of nanotechnology.

Emulsions

Emulsions PDF

Author: Tharwat F. Tadros

Publisher: Walter de Gruyter GmbH & Co KG

Published: 2016-03-21

Total Pages: 260

ISBN-13: 311045226X

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Chapter 1 General Introduction Definition of emulsions and the role of the emulsifier. Classification based on the nature of the emulsifier. Classification based on the structure of the system. General instability problems with emulsions : creaming/sedimentation, flocculation, Ostwald ripening, coalescence and phase inversion. Importance of emulsions in various industrial applications. Chapter 2 Thermodynamics of Emulsion Formation and Breakdown Application of the second law of thermodynamics for emulsion formation : Balance of energy and entropy and non-spontaneous formation of emulsions. Breakdown of the emulsion by flocculation and coalescence in the absence of an emulsifier. Role of the emulsifier in preventing flocculation and coalescence by creating an energy barrier resulting from the repulsive energies between the droplets. Chapter 3 Interaction Forces between Emulsion Droplets Van der Waals attraction and its dependence on droplet size, Hamaker constant and separation distance between the droplets. Electrostatic repulsion resulting from the presence of electrical double layers and its dependence on surface (or zeta) potential and electrolyte concentration and valency. Combination of the van der Waals attraction with double layer repulsion and the theory of colloid stability. Steric repulsion resulting from the presence of adsorbed non-ionic surfactants and polymers. Combination of van der Waals attraction with steric repulsion and the theory of steric stabilisation. Chapter 4 Adsorption of Surfactants at the Oil/Water Interface Thermodynamic analysis of surfactant adsorption and the Gibbs adsorption isotherm. Calculation of the amount of surfactant adsorption and area per surfactant molecule at the interface. Experimental techniques for measuring the interfacial tension. Chapter 5 Mechanism of Emulsification and the Role of the Emulsifier Description of the factors responsible for droplet deformation and its break-up. Role of surfactant in preventing coalescence during emulsification. Definition of the Gibbs dilational elasticity and the Marangoni effect in preventing coalescence. Chapter 6 Methods of Emulsification Pipe flow, static mixers and high speed stirrers (rotor-stator mixer). Laminar and turbulent flow. Membrane emulsification. High pressure homogenisers and ultrasonic methods. Chapter 7 Selection of Emulsifiers The hydrophilic-lipophilic-balance (HLB) and its application in surfactant selection. Calculation of HLB numbers and the effect of the nature of the oil phase. The phase inversion temperature (PIT) method for emulsifier selection. The cohesive energy ratio method for emulsifier selection. Chapter 8 Creaming/Sedimentation of Emulsions and its prevention Driving force for creaming/sedimentation: effect of gravity, droplet size and density difference between the oil and continuous phase. Calculation of the rate of creaming/sedimentation in dilute emulsions. Influence of increase of the volume fraction of the disperse phase on the rate of creaming/sedimentation. Reduction of creaming/sedimentation: Balance of the density of the two phases, reduction of droplet size and effect of addition of ''thickeners'. Chapter 9 Flocculation of Emulsions and its Prevention Factors affecting flocculation. Calculation of fast and slow flocculation rate. Definition of stability ratio and its dependence on electrolyte concentration and valency. Definition of the critical coagulation concentration and its dependence on electrolyte valency. Reduction of flocculation by enhancing the repulsive forces. Chapter 10 Ostwald Ripening and its Reduction Factors responsible for Ostwald ripening : difference in solubility between small and large droplets and the Kelvin equation. Calculation of the rate of Ostwald ripening. Reduction of Ostwald ripening by incorporation of a small amount of highly insoluble oil. Reduction of Ostwald ripening by the use of strongly adsorbed polymeric surfactant and enhancement of the Gibbs elasticity. Chapter 11 Emulsion Coalescence and its Prevention Driving force for emulsion coalescence : Thinning and disruption of the liquid film between the droplets. The concept of disjoining pressure for prevention of coalescence. Methods for reduction or elimination of coalescence : Use of mixed surfactant films, use of lamellar liquid crystalline phases and use of polymeric surfactants. Chapter 12 Phase Inversion and its Prevention Distinction between catastrophic and transient phase inversion. Influence of the disperse volume fraction and surfactant HLB number. Explanation of the factors responsible for phase inversion. Chapter 13 Characterisation of Emulsions Measurement of droplet size distribution : Optical microscopy and image analysis. Phase contrast and polarising microscopyDiffraction methods. Confocal laser microscopy. Back scattering methods Chapter 14 Industrial Application of Emulsions 14.1 Application in Pharmacy 14.2 Application in Cosmetics 14.3 Application in Agrochemicals 14.4 Application in Paints 14.5 Application in the Oil Industry

Emulsions and Emulsion Stability

Emulsions and Emulsion Stability PDF

Author: Johan Sjoblom

Publisher: CRC Press

Published: 2005-11-21

Total Pages: 684

ISBN-13: 1420028081

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Emulsions and Emulsion Stability, Second Edition provides comprehensive coverage of both theoretical and practical aspects of emulsions. The book presents fundamental concepts and processes in emulsified systems, such as flocculation, coalescence, stability, precipitation, deposition, and the evolution of droplet size distribution. The bo

Modern Aspects of Emulsion Science

Modern Aspects of Emulsion Science PDF

Author: Bernard P Binks

Publisher: Royal Society of Chemistry

Published: 2007-10-31

Total Pages: 443

ISBN-13: 1847551475

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Emulsions occur either as end products or during the processing of products in a huge range of areas including the food, agrochemical, pharmaceutical, paint and oil industries. Despite over one hundred years of research in the subject, however, a quantitative understanding of emulsions has been lacking. Modern Aspects of Emulsion Science presents a comprehensive description of both the scientific principles in the field and the very latest advances in research in this important area of surface and colloid science. Topics covered include emulsion formation, type, stability (creaming, flocculation, ripening, coalescence), monodisperse and gel emulsions, and applications. Emphasis has been placed on relating the chemistry of the surfactant or protein adsorbed at the oil-water interface to the principles of the physics involved in the bulk emulsion property. The book has been written by a collection of the world's leading experts in the field, and covers both experimental and theoretical approaches. Modern Aspects of Emulsion Science fills a real gap in the market, being the only book of its kind in print. As such it will prove essential reading for graduates and researchers in this subject, in both academia and industry.

Nanoemulsions

Nanoemulsions PDF

Author: Seid Mahdi Jafari

Publisher: Academic Press

Published: 2018-02-24

Total Pages: 665

ISBN-13: 0128118393

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Nanoemulsions: Formulation, Applications, and Characterization provides detailed information on the production, application and characterization of food nanoemulsion as presented by experts who share a wealth of experience. Those involved in the nutraceutical, pharmaceutical and cosmetic industries will find this a useful reference as it addresses findings related to different preparation and formulation methods of nanoemulsions and their application in different fields and products. As the last decade has seen a major shift from conventional emulsification processes towards nanoemulsions that both increase the efficiency and stability of emulsions and improve targeted drug and nutraceutical delivery, this book is a timely resource. Summarizes general aspects of food nanoemulsions and their formulation Provides detailed information on the production, application, and characterization of food nanoemulsion Reveals the potential of nanoemulsions, as well as their novel applications in functional foods, nutraceutical products, delivery systems, and cosmetic formulations Explains preparation of nanoemulsions by both low- and high-energy methods

Emulsion Science

Emulsion Science PDF

Author: Jerôme Bibette

Publisher: Springer

Published: 2003-07-01

Total Pages: 148

ISBN-13: 3540708200

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Emulsions occur either as end products or during the processing of products in a huge range of areas including the food, agrochemical, pharmaceuticals, paints and oil industries. As end products, emulsions allow to avoid organic solvent in processing hydrophobic coatings. Emulsion technology is a suitable approach to vehicle viscous phases. It is also a remarkable mean of targeting actives or capturing specific species. The range of applications of emulsions progresses and their manufacturing becomes more and more sophisticated. Besides this broad domain of technological interest, emulsions are raising a variety of fundamental questions at the frontier between physic and chem istry. Indeed, as a class of soft colloidal materials, emulsions science is linked to various aspects of these disciplines: phase transitions, surface forces and wetting, metastability and hydrodynamic instabilities, mechanical properties and flow. The aim of this book is to review the main important concepts governing emulsion science. In Chapter 2, repulsive interactions between liquid films are discussed as well as adhesive interaction related to wetting. In Chap ter 3, consequences of weak and strong attractions are presented, related to the well accepted liquid solid transition analogy. In Chapter 4, the basics of both bulk compressibility and shear elasticity are presented, the role of disorder being the most important aspect of the elastic behavior of these soft systems. In Chapter 5 the central question of the emulsion lifetime related to metastability is discussed.

Food Emulsions

Food Emulsions PDF

Author: David Julian McClements

Publisher: CRC Press

Published: 2015-08-21

Total Pages: 714

ISBN-13: 1498726690

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Continuing the mission of the first two editions, Food Emulsions: Principles, Practices, and Techniques, Third Edition covers the fundamentals of emulsion science and demonstrates how this knowledge can be applied to control the appearance, stability, and texture of emulsion-based foods. Initially developed to fill the need for a single resource co

Applied Surfactants

Applied Surfactants PDF

Author: Tharwat F. Tadros

Publisher: John Wiley & Sons

Published: 2006-03-06

Total Pages: 654

ISBN-13: 3527604537

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While currently available titles either focus on the basics or on very specific subtopics, this text meets the need for a comprehensive survey of surfactants and their properties, with a strong emphasis on applications and their correlation to the fundamentals. The author covers their classification, physical properties, phase behavior, adsorption, effects - such as wetting, spreading and adhesion - as well as industrial applications in personal care and cosmetics, pharmaceuticals, agrochemicals and food products. Professor Tadros is a well-known expert on the topic of surfactants, with much experience in colloid science. Here, he uses his industrial experience to close the gap between fundamentals of surfactants and their relevance and applications in practice.

Emulsions, Foams, and Suspensions

Emulsions, Foams, and Suspensions PDF

Author: Laurier L. Schramm

Publisher: John Wiley & Sons

Published: 2006-05-12

Total Pages: 463

ISBN-13: 3527606882

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Until now colloid science books have either been theoretical, or focused on specific types of dispersion, or on specific applications. This then is the first book to provide an integrated introduction to the nature, formation and occurrence, stability, propagation, and uses of the most common types of colloidal dispersion in the process-related industries. The primary focus is on the applications of the principles, paying attention to practical processes and problems. This is done both as part of the treatment of the fundamentals, where appropriate, and also in the separate sections devoted to specific kinds of industries. Throughout, the treatment is integrated, with the principles of colloid and interface science common to each dispersion type presented for each major physical property class, followed by separate treatments of features unique to emulsions, foams, or suspensions. The first half of the book introduces the fundamental principles, introducing readers to suspension formation and stability, characterization, and flow properties, emphasizing practical aspects throughout. The following chapters discuss a wide range of industrial applications and examples, serving to emphasize the different methodologies that have been successfully applied. Overall, the book shows how to approach making emulsions, foams, and suspensions with different useful properties, how to propagate them, and how to prevent their formation or destabilize them if necessary. The author assumes no prior knowledge of colloid chemistry and, with its glossary of key terms, complete cross-referencing and indexing, this is a must-have for graduate and professional scientists and engineers who may encounter or use emulsions, foams, or suspensions, or combinations thereof, whether in process design, industrial production, or in related R&D fields.

Food Emulsions

Food Emulsions PDF

Author: David Julian McClements

Publisher: CRC Press

Published: 2004-12-16

Total Pages: 633

ISBN-13: 1420039431

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Food Emulsions: Principles, Practice, and Techniques, Second Edition introduces the fundamentals of emulsion science and demonstrates how this knowledge can be applied to better understand and control the appearance, stability, and texture of many common and important emulsion-based foods. Revised and expanded to reflect recent developments, this s