2 edition of Influence of pressure on the structure and stability of microemulsions. found in the catalog.
Influence of pressure on the structure and stability of microemulsions.
Thesis (Ph.D), University of East Anglia, School of Chemical Sciences, 1990.
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable). Emulsions are part of a more general class of two-phase systems of matter called gh the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one . Insulin-loaded microemulsions for transdermal delivery were developed using isopropyl myristate or oleic acid as the oil phase, Tween 80 as the surfactant, and isopropyl alcohol as the cosurfactant. The pseudoternary phase diagrams were constructed to determine the composition of microemulsions. The insulin permeation flux of microemulsions containing oleic acid as Cited by: Characterization of soil structure: (mostly qualitative, since is a function of time) 1. Size - Particles (particle size distribution) - Aggregates (dry-sieving; water stability test by wet-sieving) - Porosity 2. Morphological - Blocky - Plately - Prismatic 3. Physical - Pore size distribution - water desorption method Volume fraction of File Size: KB. Soils and Foundations Chapter 3 Bangladesh National Building Code 6‐ ALLOWABLE BEARING CAPACITY: The maximum net average pressure of loading that the soil will safely carry with a factor of safety considering risk of shear failure and the settlement of foundation.
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Influence of pressure on the structure and stability of microemulsions. Author: Eastoe, Julian. ISNI: Awarding Body: University of East Anglia Current Institution: University of East Anglia Date of Award: Availability of Full Text. Ternary diagrams have Influence of pressure on the structure and stability of microemulsions.
book constructed for 3 specific microemulsion systems showing the effects of salinity and cosurfactant on phase behavior, viscosity, Influence of pressure on the structure and stability of microemulsions.
book, optical birefringence, and interfacial tension. Using these Influence of pressure on the structure and stability of microemulsions. book, micellar structure maps. The effect of pressure and temperature on the stability and structure of low-density water-in-oil microemulsions in propane (ρ≈ → g cm –3) has been studied with three different surfactants Aerosol-OT (anionic), DDAB (cationic) and C 12 E 5 (non-ionic).Small-angle neutron scattering (SANS) measurements were made using a specially constructed high-pressure Cited by: In microemulsion technique, first a hot microemulsion is produced by stirring low-melting lipids and then dissolving the drug in the resulting melted solid lipids.
Then surfactant, cosurfactant, and water are added. The resulting combination is poured into a large amount of cold water. Besides temperature, hydrostatic pressure has been used as a physical-chemical parameter for studying the energetics and phase behavior of membrane systems.
First we review some theoretical aspects of lipid self-assembly. Then, the temperature and pressure dependent structure and phase behavior of lipid bila Membrane biophysicsCited by: Thermodynamic stability: The stability and shelf life of the formulation is improved due to the thermodynamic stability of the microemulsion.
• Microemulsions are thermodynamically stable, and consist of small droplets which possess large interfacial area. These characteristics facilitate their use in nanoparticle synthesis. the formation of the emulsion and its long-term stability [1–3].
Emulsions may be classiﬁed according to the nature of the emulsiﬁer or the structure of the system. This is illustrated in Table Nature of the Emulsiﬁer ThesimplesttypeisionssuchasOH− that can be speciﬁcally adsorbed on the emulsion droplet thus producing a Size: KB. microemulsions, can severely a ect their native structure .
To alleviate this problem, cryo‐ To alleviate this Influence of pressure on the structure and stability of microemulsions. book, cryo‐ electron microscopy (cryo‐EM) techniques have been utilized. Microemulsions are readily distinguished from normal emulsions by their transparency, low viscosity and more fundamentally their thermodynamic stability.
Drug delivery through microemulsions is a promising area for continued research with the aim of achieving controlled release with enhanced bioavailability and for drug targeting to various. The effective use of microemulsions has increased dramatically during the past few decades as major industrial applications have expanded in a variety of fields.
Microemulsions: Properties and Applications provides a complete and systematic assessment of all topics affecting microemulsion performance and discusses the fundamental.
Beginning over 40 y ago, a curious type of microemulsions—as transparent dispersion of two immiscible liquids separated by an interfacial film—at thermodynamic equilibrium has been described as “pre-Ouzo,” “detergentless,” or surfactant-free microemulsions.
The experiments in ternary systems containing one hydrotropic cosolvent Cited by: Microemulsions: Structure & Dynamics 1st Edition by Stig Friberg (Editor), Pierre Bothorel (Editor) ISBN ISBN Why is ISBN important.
ISBN. This bar-code number lets you verify that you're getting exactly the right version or edition of a book. translucent appearance. For microemulsions, once the conditions are right, spontaneous formation occurs. As for simple aqueous systems, microemulsion formation is dependent on surfactant type and structure.
If the surfactant is ionic and contains a single hydrocarbon chain (e.g., sodium dodecylsulphate,File Size: KB. Microemulsions: Theory and Practice covers the development of the theory and practice of microemulsion systems.
This book is divided into seven chapters that explore the physics and chemistry of microemulsions. This book deals first with the commercial history of microemulsions, from the discovery of carnauba wax emulsions to polymer Edition: 1. The trend of growing interest in alternative source of energy focuses on renewable products worldwide.
However, the situation of petroleum industries in many countries needs much concern in improving the oil recovery technique. Chemical method, especially microemulsion flooding, plays an important role in enhanced oil recovery technique due to its ability to reduce Cited by: There was a strong correlation between the specific structure of the microemulsion systems and their electrical conductive behavior.
16 The phase systems (o/w or w/o) of the microemulsions were determined by measuring the conductivity of the microemulsions. 17 The ME formulations had the average conductivity in the range of Cited by: molecule surfactant-stabilised o/w emulsions by high pressure homogenisation and ii) isopropyl myristate and Imwitor ) were investigated for their influence on the solubilisation of oil molecules from emulsion droplets into surfactant micelles, thus the formation of nano- and microemulsion.
heat treatment on the stability of File Size: 7MB. The structure, dynamics and transport behaviors of microemulsions are physicochemically unique and need exploration for basic understanding of their. Mechanism of formation and structure of micro emulsions by electron microscopy, J.
Phys. Chem. 63 () – 4 I. Danielsson, B. Lindman, The definition of a microemulsion, Colloids and Surfaces 3 () – 5 M.J. Lawrence, G.D.
Rees, Microemulsions-based media as novel drug delivery systems, Advanced. Introduction to Dynamics of Structures 2 Washington University in St. Louis One degree of freedom We can model the building shown in figure 1 as the simple dynamically equivalent model shown in figure 3a.
In this model, the lateral stiffness of the columns is modeled by the spring (k), the damping is modeled by the shock absorber (c) and. Phase behavior. Characterization of microemulsions necessarily begins with the elucidation of the phase behavior, where, in the most simple form, oil, water, and surfactant are mixed in different molar ratios, and the formed phases are tracked .A generic phase diagram resulting from such analysis is shown in Figure several regions of the phase diagram, single Cited by: 1.
As a multiple-unit dosage form, they assist smooth passage in the gut and, because of the formation of microemulsion in contact with gastric fluids, they present the drug dissolved in fine oil/surfactant droplets.
Therefore, stability and absorption are improved and dose dumping and variability in plasma levels are by: Bicontinuous Polymeric Microemulsions from Polydisperse Diblock Copolymers. The Journal of Physical Chemistry B(12), DOI: /jpb. Witten. Spontaneous Free-Boundary Structure in Crumpled by: Ionic Liquids in Microemulsions – a Concept to Extend the Conventional Thermal Stability Range of Microemulsions Dissertation Presented for the Degree of Doctor of Natural Sciences (Dr.
rer. nat.) University of Regensburg Natural Sciences Faculty IV Chemistry & Pharmacy Oliver Zech Regensburg File Size: 3MB. Prof. Nissim Garti is a staff member at the Casali Institute of Applied Chemistry in the Hebrew University of Jerusalem in ISRAEL. He specializes in interfacial phenomena, emulsion technology, microemulsions, crystallization phenomena, nutraceuticals and food science.
Overall, the o/w microemulsions were found to form at a small region of the ternary phase diagrams with a relatively large ratio of water, compared to w/o nanoemulsion, along dilution lines 1 and 2.
On the other hand, w/o microemulsions were determined at the corner of surfactant-rich region along dilution lines 1, 2, 3 and 4 in the ternary Cited by: 2. On the stability of surfactant-free water-in-oil emulsions and synthesis of hollow SiO2 nanospheres.
Microemulsions: Structures, surfactant layer properties and wetting transitions. Abillon, L.T. Lee, The influence of pressure and electrolyte on the phase behaviour of systems with anionic surfactants: The system water + heptane + sds. The first two volumes cover the role of surface forces, while the third looks at colloid stability and its application in pharmacy.
Volume 4 deals with applications in personal care and cosmetics, while the last two volumes cover colloids in agrochemicals and in paints and coatings.
Factors affecting the stability of emulsions stabilised by biopolymers The solubility and behaviour of biopolymers is dependent on various factors, such as pH, ionic strength, temperature, nature of biopolymers and medium, presence of other agents such as surfactants in the system and charge of biopolymers [ 10, 41 ].Author: Yvonne Maphosa, Victoria A.
Jideani. PhD - UEA - Influence of Pressure on Microemulsions. BSc II(i) Chemistry, University of East Anglia. A' Levels - Chemistry A - Physics A - Mathematics B. Solihull 6th Form College. Special awards.
In I was awarded the Rideal Medal, which is a prestigious UK national award from the RoyalFile Size: KB. Microemulsions are clear, thermodynamically stable, isotropic liquid mixtures of oil, water and surfactant, frequently in combination with a cosurfactant.
The aqueous phase may contain salt and/or other ingredients, and the "oil" may actually be a complex mixture of different hydrocarbons and olefins.
In contrast to ordinary emulsions, microemulsions form upon simple mixing of. Microemulsions as media for enzyme catalyzed reactions 49 Microemulsions as liquid membrane carrier agents 50 Microemulsion gels 51 Microemulsions as blood substitutes 55 Microemulsions for drug delivery 5~ Water-in-oil microemulsions 61 Oil-in-water microemulsions.
64 Chapter Two: Experimental Microemulsions Self-Assembled Structures in Applications Polymers Stability of Protein Structure in Aqueous Solution.
DLVO Theory of Colloid Stability Influence of Polymers on Colloidal Stability. Aggregation Kinetics Morphology of Colloidal Aggregates Rheology, with Special Attention to Dispersions and Interfaces. Both the placing of microemulsions in the book and the text devoted to this topic reveal that even inwhen the third edition was published, microemulsions had received very little attention in the pharmaceutical field and that, furthermore, the nature of microemulsions was misunderstood.
In the first work on microemulsion structure by. The aim of this work was to investigate the phase behaviour and the structure of the n-hexane/water emulsions based on a nonionic, nontoxic and biocompatible surfactant, Tween This system is of interest for new pharmaceutical techniques based on supercritical fluids to form nano- and encapsulated particles.
However, it showed a lack of stability denoted by large Cited by: A Phase Diagram Approach to Microemulsions. Physicochemistry of W/O Microemulsions: Formation, Stability, and Droplet Clustering.
Percolating Phenomenon in Microemulsions: Effect of External Entity. Influence of Polyethylene Glycols and Polyethylene Glycol Dimethyl Ethers upon the Internal Dynamics of Water in Oil Microemulsions. Beginning with P.A. Winsor's fundamental hypothesis on a natural interfacial curvature depending on the values of the formulation variables, this unique book shows scientists how to understand the intrinsic structure of these complex systems and their corresponding physical properties predict how a change in one formulation variable (surfactant structure, oil structure, aqueous Authors: Robert Schechter, Maurice Bourrel.
Nanoemulsions versus microemulsions: terminology, differences, and similarities David Julian McClements DOI: /c2smb Colloidal delivery systems based on microemulsions or nanoemulsions are increasingly being utilized in the food and pharmaceutical industries to encapsulate, protect, and deliver lipophilic bioactive components.
The dynamic and equilibrium aspects of micellar and microemulsion systems have been investigated with focus on the influence of alcohols, oils, and salinity on the systems. The pressure-jump method was used to study the micellization kinetics. The obtained slow relaxation time is related to the average life-time of micelles.
Quercetin can bring many benefits to skin based on its various bioactivities. However, the therapeutic effect of quercetin is limited due to the poor water solubility, pH instability, light instability, and skin permeation.
The aim of the present work was applying essential oil-based microemulsions to improve the solubility, pH stability, photostability, and Cited by: 8. The pdf barometric pressure is synonymous with the term air pressure when describing conditions in the atmosphere, and pdf also be referred to as atmospheric pressure.
Like all matter, air is composed of molecules. These molecules have mass and are subjected to the force of Earth’s gravity. Air pressure is the weight of air molecules.the thermodynamically stable microemulsions which form spontaneously,23 The major diﬀerences between classical emulsions (or macroemulsions), nanoemulsions and micro-emulsions is in droplet size range and stability characteristics, as summarized in Fig.
1. Macroemulsions and nanoemulsions. Emulsions: Formation, Stability, Industrial Ebook - Ebook written by Tharwat F. Tadros. Read this book using Google Play Books app on your PC, android, iOS devices. Download for offline reading, highlight, bookmark or take notes while you read Emulsions: Formation, Stability, Industrial : Tharwat F.