Arrested Coalescence, Interfacial Phenomena and Stability of Oil-water Emulsions PDF Download
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Author: Abigail Thiel
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Many foods are emulsions like salad dressings, soups, and gravies where there is a dispersed and continuous phase. Most emulsified products are formulated for long term stability; however, aerated emulsions like ice cream, whipped topping, and whipped cream are purposefully destabilized to allow fat globules to partially coalesce. In fact, fat destabilization is key to attain the desired sensorial and rheological properties. This study is divided into three distinct phases, each helping to better understand the conditions that destabilize emulsions and how it can be controlled. The first phase of this project used micromanipulation techniques to observe the entire coalescence event between two fat globules from initial contact to the final relaxed structure achieved. During these experiments, the role of different emulsifiers, thickeners, co-surfactants, solid fat contents (SFC), fat types, and droplet sizes were investigated for their effect on partial coalescence. Coalescence was measured as strain or linear deformation before and after droplets were put in contact. The second part of this project studied the partitioning behavior of fat crystals in oil-in-water emulsions. Depending on the location of fat crystals, they can either stabilize or destabilize emulsions. Micromanipulation studies revealed that interfacial fat crystals could not penetrate into a neighboring oil droplet protected with a methylcellulose coating. However, the neighboring droplet became susceptible to destabilization, even with a methylcellulose coating, if a small amount of fat crystallization occurred near the interface. Although micromanipulation experiments will lead to a better understanding of the coalescence behavior between two fat globules; the third phase investigated larger fat networks to better mimic partial coalescence in foods. To study multi-droplet networks, a method was developed to direct fat globules into the same area to interact and the resulting network was analyzed using computational modeling Ultimately, this work will provide better control for production of aerated emulsions containing partially-coalesced fat globule networks, or other complex microstructures, to enable prediction of emulsion stability.
Author: Abigail Thiel
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Many foods are emulsions like salad dressings, soups, and gravies where there is a dispersed and continuous phase. Most emulsified products are formulated for long term stability; however, aerated emulsions like ice cream, whipped topping, and whipped cream are purposefully destabilized to allow fat globules to partially coalesce. In fact, fat destabilization is key to attain the desired sensorial and rheological properties. This study is divided into three distinct phases, each helping to better understand the conditions that destabilize emulsions and how it can be controlled. The first phase of this project used micromanipulation techniques to observe the entire coalescence event between two fat globules from initial contact to the final relaxed structure achieved. During these experiments, the role of different emulsifiers, thickeners, co-surfactants, solid fat contents (SFC), fat types, and droplet sizes were investigated for their effect on partial coalescence. Coalescence was measured as strain or linear deformation before and after droplets were put in contact. The second part of this project studied the partitioning behavior of fat crystals in oil-in-water emulsions. Depending on the location of fat crystals, they can either stabilize or destabilize emulsions. Micromanipulation studies revealed that interfacial fat crystals could not penetrate into a neighboring oil droplet protected with a methylcellulose coating. However, the neighboring droplet became susceptible to destabilization, even with a methylcellulose coating, if a small amount of fat crystallization occurred near the interface. Although micromanipulation experiments will lead to a better understanding of the coalescence behavior between two fat globules; the third phase investigated larger fat networks to better mimic partial coalescence in foods. To study multi-droplet networks, a method was developed to direct fat globules into the same area to interact and the resulting network was analyzed using computational modeling Ultimately, this work will provide better control for production of aerated emulsions containing partially-coalesced fat globule networks, or other complex microstructures, to enable prediction of emulsion stability.
Author: Tharwat F. Tadros
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110366479
Category : Science
Languages : en
Pages : 418
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Book Description
The main objective of this volume is to demonstrate the importance of the fundamental aspects of interfacial phenomena in various industrial applications. The text provides the reader with the knowledge that is essential for the composition of the complex multi-phase systems used in the above mentioned areas of application. It should enable the physical and formulation chemist as well as the chemical engineer in designing the formulation on the basis of a rational approach. It will also enable the formulation scientist to better understanding the factors responsible for producing a stable product with optimum application conditions. The book should also be very useful for teaching the subject of formulation at academic institutions.
Author: Tharwat F. Tadros
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110283433
Category : Science
Languages : en
Pages : 358
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Book Description
This fundamental book on interfacial phenomena forms the basis of application of interface and colloid science to various disperse systems. These include suspensions, emulsions, nano-dispersions, wetting, spreading, deposition and adhesion of particles to surfaces. These systems occur in most industrial applications, such as personal care and cosmetic formulations, pharmaceutical systems particularly for controlled and targeted delivery of drugs, agrochemical formulations and enhancement of their biological performance, paints and coatings as well as most food formulations. These applications are described in volume 2. The text is very valuable for formulation chemists, chemical engineers and technologies who are involved in such applications. In addition this fundamental text is also valuable for research scientists and Ph.D. students investigating various aspects of interface and colloid science.
Author: Yu Song
Publisher: John Wiley & Sons
ISBN: 3527341064
Category : Science
Languages : en
Pages : 576
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Book Description
The first book offering a global overview of fundamental microfluidics and the wide range of possible applications, for example, in chemistry, biology, and biomedical science. As such, it summarizes recent progress in microfluidics, including its origin and development, the theoretical fundamentals, and fabrication techniques for microfluidic devices. The book also comprehensively covers the fluid mechanics, physics and chemistry as well as applications in such different fields as detection and synthesis of inorganic and organic materials. A useful reference for non-specialists and a basic guideline for research scientists and technicians already active in this field or intending to work in microfluidics.
Author: Tharwat F. Tadros
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110587947
Category : Science
Languages : en
Pages : 430
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Book Description
Volume 1 of Formulation Science and Technology is a survey of the theory of formulations in a variety of fields, as well as their rheological characterization. It offers in-depth explanations for research scientists, universities, and industry practitioners looking for a complete understanding of how different formulations behave and how to influence their performance.
Author: Rebecca Balaj
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Complex fluids are of increasing interest because of their ability to provide a unique environment for the exploration of interfacial phenomena. Emulsions, which are mixtures of immiscible liquids, allow for separation of reagents whilst simultaneously providing a liquid-liquid interface wherein reactants can be easily transported, and reactions are able to readily occur. Thus, utilizing complex emulsions as dynamic materials is potentially important to understand localized reaction pathways and kinetics in a controllable and predictable manner. However, a significant limitation of fluid droplets for long-term applications is their eventual breakdown over time. Elucidating approaches by which to enhance droplet stability while simultaneously maintaining their reconfigurability and responsive character is therefore essential. This dissertation, thus, exists in three main sections: first, it aims to investigate a surfactant-free gelation pathway to form oil-core hydrogel capsules to stabilize complex droplets; secondly, it examines the non-equilibrium partitioning of amphiphilic surfactants into biphasic emulsions of miscible oils to dynamically and controllably induce phase separation; and, finally, it attempts to explore the reconfigurable complex droplet as a responsive soft material which can be used to easily manipulate chemical reactions at the oil-water interface. One approach to enhanced stabilization of droplets is by encapsulation, where a shell, often a polymer, encases the liquid droplet to prevent coalescence and limit exchange of droplet contents with the continuous phase. A common approach to droplet encapsulation is interfacial polymerization, where monomers dissolved in immiscible phases react to form capsules localized at the interface. Hydrogels, which are composed of crosslinked, charged polymers swollen in water, are highly permeable to molecules in the aqueous phase and would permit the diffusion of surfactants or other analytes to the droplet surface to trigger a response in droplet configuration. In the first major project of this work, we utilized a Pickering complex droplet intermediate to localize hydrogel formation at the droplet-continuous phase interface. Enhanced stability of droplets with both ionically and covalently crosslinked capsules was observed, with a complete spectrum of reconfigurability possible upon addition of droplet-internal fluorosurfactant, Capstone FS-30. The next major work examines the partitioning of surfactant molecules across the droplet oil-water interface. In general, the partitioning of chemicals across interfaces and their subsequent concentration into droplets and coacervates is important in many fields of study, including organic reaction chemistry and in mimicking individual properties of natural systems, such as living cells. When considering partitioning occurring within emulsions, the dynamics and relative concentration of all components--oil, water, and surfactant--are critical to understanding the behavior of non-equilibrium systems. We became interested in the dynamics and degree of surfactant partitioning while examining the behavior of two-component oil droplets in aqueous surfactant. We produced microscale droplets containing two oils, which in bulk at room temperature are miscible in all proportions. Upon preparing this emulsion, we expected that the droplets would remain in a single phase during their lifetime when undergoing micellar solubilization; however, we noticed phase separation occurring within the droplets. To confirm the partitioning of surfactant into these droplets, we developed a protocol for the LCMS analysis of single microscale droplets. Furthermore, we have shown that, upon addition of ionic surfactant, we can controllably and dynamically induce phase separation through various stimuli. In the last major project of this work, we examine reaction rates at oil-water interfaces and within surfactant micelles. Reactions occurring at the interface of immiscible fluids are important for a variety of different fields, largely due to the separation of reagents into distinct phases only to be reacted specifically and controllably at the interface. This allows unique opportunity to tune reaction kinetics, location, and pathways. Studies have previously been conducted observing reaction kinetics at the oil-water interfaces of emulsions, therefore exploring reactions at interfaces in complex droplets should then allow for an even more specific morphology-dependent, tunable reaction environment.
Author: J.T. Davies
Publisher: Elsevier
ISBN: 0323161669
Category : Science
Languages : en
Pages : 511
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Book Description
Interfacial Phenomena explores the more primary properties of different liquid interfaces. This book is divided into eight chapters, where Chapter 1 establishes the basic concepts of the physics of surfaces, including the properties of matter in the surface layer. Chapters 2 and 3 further discuss the concepts of electrostatic and electrokinetic phenomena, respectively. Other areas discussed in the later chapters include adsorption at liquid interfaces; properties of monolayers; reactions at liquid interfaces; and mass transfer across interfaces. Chapter 8 discusses the more relevant aspects of disperse systems and adhesion as related to the interfacial properties discussed in the previous chapters. The text is a valuable source of information to students and researchers in the fields of chemistry, biology, and chemical engineering and can also be used for industrial and academic laboratories.
Author: K.L. Mittal
Publisher: CRC Press
ISBN: 1482270315
Category : Technology & Engineering
Languages : en
Pages : 520
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Book Description
This volume presents the acomplishments of over 85 internationlly renowned scientists whose work was influenced by Professor Wasan's groundbreaking research on interfacial phenomena at The Illinois Institute of Technology, Chicago.
Author: Graham Buckton
Publisher: CRC Press
ISBN: 1482296780
Category : Medical
Languages : en
Pages : 314
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Book Description
Interfaces are of vital importance to many fields of application, but the phenomena are hard to visualise and the theories are often linked to complex mathematical models. This book, the fifth volume in the Drug Targeting and Delivery book series, provides students and working scientists with a readable text on interfacial phenomena. It does not hide away from the complex issues, but addresses the subject in a manner which will make it accessible to the scientist without previous experience of interfacial science. The book looks at a wide range of pharmaceutical issues, ranging from product development to research linked to in vivo applications.
Author: Prem Kumar Bikkina
Publisher:
ISBN:
Category : Emulsions
Languages : en
Pages : 370
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Book Description
