This article contains the results of experimental investigation of the rheological characteristics and structures of emulsions and suspensions. The rheological behavior of materials can be regarded as being between two extremes. Click download or read online button to get rheology of pharmaceutical emulsions book now. The shear rheology of an emulsion of viscous drops in the presence of finite inertia is investigated using direct numerical simulation. This study compared the effects of oil concentration and. Rheology is the science in which flow characteristics and deformation of any kind of material including gas, liquid, and solid are studied.
The issue of rheology in food emulsions is closely linked to the texture, taste, and mouth feel of foods obtained from these emulsions. Rheology centre rheology analysis viscosity testing. The rate of absorption of an ordinary suspension differs from thixotropic suspension. The liquid droplets the disperse phase are dispersed in a liquid medium the continuous phase. Uniform electricfieldinduced nonnewtonian rheology of a dilute suspension of deformable newtonian drops. We present data for the rheology of suspensions of monodisperse particles. Rheology of suspensions colloid suspension chemistry. Inertial effects on the rheology of a dilute emulsion. Solids are said to have an elastic response, and can resist. We have an extensive breadth and depth of experience of the measurement of rheological and viscosity properties of a huge variety of materials ranging from solutions, suspensions and emulsions to slurries, waxes, pastes and set gels. This webinar will showcase the power of rheomicroscopy for an accurate interpretation of rheological data in the context of three case studies, each on a different material and using a. A generalized equation for rheology of emulsions and suspensions of deformable particles subjected to simple shear at low reynolds number article pdf available in rheologica acta november.
It applies to substances which have a complex structure, including muds, sludges, suspensions. The relevance of the dynamic nature of the interface is stressed throughout, from the disperse to the cocontinuous morphology. Food rheology encyclopedia of life support systems. In the limiting case of dilute emulsions, the discussion is based on the analogy and differences in properties of suspensions and emulsions.
University of mauritius bachelor of pharmacy year 2 pharmaceutics iii title. Its application to suspensions of hard and soft particles would allow insight into their different rheology and yielding that is a direct result of the elastic properties of the constituent particles. Influence of nonionic surfactant addition on the stability and rheology of particlestabilized emulsions. A generalized equation for rheology of emulsions and. The second section reports on the rheology of liquidliquid suspensions, i. Rheology of concentrated soft and hardsphere suspensions.
A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Figure 2 indicates the different types of emulsions. The product is easily administered from bottle or via syringe needle 2. Emulsions rheology of suspensions many pharmaceutical products, particularly those for children, are presented as suspension and their rheological properties are important. Hubbe, a pegah tayeb, a michael joyce, a preeti tyagi, a margaret kehoe, a,b katarina dimicmisic, c and lokendra pal a the flow characteristics of dilute aqueous suspensions of cellulose nanocrystals cnc, nanofibrillated cellulose nfc, and related products in dilute aqueous suspensions could be of great. Rheology of suspensions and emulsions rheology emulsion. Request pdf rheology and structure of emulsions and suspensions this article contains the results of experimental investigation of the rheological. Viscosity of a structured fluid as a function of shear rate and particle concentration1. A generalized equation for rheology of emulsions and suspensions of deformable particles subjected to simple shear at low reynolds number. Oscillatory rheology measuring the viscoelastic behaviour of soft materials measuring this time dependent stress response at a single frequency immediately reveals key differences between materials, as shown schematically in figure 1b.
Start studying pharmaceutics colloids, suspensions, emulsions and rheology. Application note rheology of pharmaceutical suspensions. Rheological measurements of compounded emulsions and. Food, biopolymers, colloids, foam, emulsion, suspension, processing, rheometry, gel. Rheology on the way from dilute to concentrated emulsions. During the laboratory exercise, students learned the proper use of a.
The viscosity of semisolid products may affect absorption of these topical products due to the effect of viscosity on the rate of diffusion of the active ingredients. The development and production of good quality emulsions depend on the knowledge of emulsion preparation, stability mechanisms. Rheology and structure of emulsions and suspensions article in journal of dispersion science and technology 332. Emulsion formation, stability, and rheology tharwat f. To the pharmacist, rheology is important in the flow of emulsions, through colloid mills, triturating suspensions in mortar and pestle and mechanical properties of glass or plastic containers and of rubber closures. Rheology of suspensions and emulsions authorstream presentation. The reader will quickly appreciate the breadth of the subject area and, furthermore, that mastering colloidal suspension rheology requires some basic knowledge in colloid science as well as rheology. Rheology of suspensions rheology of dispersions wiley. The stress conditions normally employed for evaluating the stability of emulsions include. Reflectance of the emulsions was determined by at 450 m. The ow emulsions, containing 5 vol of the dispersed phase, the oil phase was colored with red dye, scarlet b.
Between 1966 and 1969, he spent a sabbatical at the agricultural university of wageningen and t. Suspensions are usually dispensed in bottles or sachets and are taken from a spoon. Rheology of suspensions factors considered are viscosity of a suspension change in flow properties of the suspension spreading qualities of. Introduction to the rheology of colloidal dispersions with emphasis on practical interpretation of rheological measurements on colloidal dispersions. Rheology on the way from dilute to concentrated emulsions s. Rheology of emulsions advances in chemistry acs publications.
A basic introduction to rheology rheology and viscosity introduction. Emulsions have been widely used in different industrial processes. Understanding rheology of structured fluids keywords. The rheological behavior of clay suspensions, oilinwater emulsions, and their blends was investigated using a controlledstress rheometer. The emulsions had the oil volume fraction in the range from 0. Mason corporate research science laboratory, exxon research and engineering co. In the limiting case of dilute emulsions, the discussion is based on the analogy keywords. Ii suspensions, emulsions and foams pier luca maffettone, francesco greco. Rheology of attractive emulsions harvard university. Pdf emulsion types, stability mechanisms and rheology.
Nonlinear rheology of colloidal suspensions probed by. Rheology of pharmaceutical emulsions download ebook pdf. Practical re commendations for shelf life predictions of emulsions. Several factors can easily affect the rheology of emulsions and it may be considered that they are related to the properties of the phases. A discussion of the rheology of suspensions and how it relates to that of emulsions is given.
Flow in pipelines and constraining media applications in pipeline flow. We present analyses to provide a generalized rheological equation for suspensions and emulsions of nonbrownian particles. The suspensions exhibited newtonian behavior at low solids volume fractions. We first consider the effect of a single deformable fluid particle on the ambient velocity and stress fields to constrain the rheological behavior of dilute mixtures. The rheological behavior of particleoil suspensions and wo pickering emulsions consisting of water, 1dodecene and different fumed silica nanoparticles was investigated. An introduction to colloidal suspension rheology youtube. The rheological properties of both liquid and semisolid. Ii food rheology mats stading encyclopedia of life support systems eolss food rheology mats stading sik the swedish institute for food and biotechnology and chalmers university of technology, gothenburg, sweden keywords. Shear viscosity of concentrated suspensions of viscoelastic particles in concentrated suspensions, hydrodynamic interactions enhance shear gradients and particle deformation but the flowinduced anisotropic microstructures lead to a decrease in viscous dissipation and suspension apparent viscosity. There are several types of emulsions depending on how the oil and water phases are located in the dispersed system.
Rheology of emulsionfilled alginate microgel suspensions. Understanding the principles that govern the flow characteristics of the dispersions is essential for formulating a dispersion and its longterm stability1,2. Rheology of suspensions free download as powerpoint presentation. Rheology of emulsions performance of the emulsion depends on flow properties. Pdf rheology of emulsions svetlana derkach academia. This webinar will showcase the power of rheomicroscopy for an accurate interpretation of rheological data in the context of three case studies, each on a different material and using a different rheometry technique. An illustration of the types of shear induced orientation which can occur for various shear thinning materials is shown in figure 4. Deformability of the interface, together with breakup and coalescence phenomena play. Rheology of systems with soft or electrostatic interaction. Help solve your surfactant, emulsion, foam, and suspension problems in this course designed for scientists and engineers engaged in research and development in the chemical, petroleum, coatings, food, electronics, pharmaceutical, cosmetics, and personal care products industries. In general these properties must be considered so that. The emulsions of kerosene in water were shearthinning over the oil volume fraction range of 0.
Steady shear rheology of a viscous emulsion in the. By recasting our data in terms of the einstein coefficient, we relate our rheological observations to the underlying particle motions via jefferys jeffery 1922 proc. The study of rheology can be used to evaluate the behavior of particles in a liquid vehicle. These relationships can be used to predict the rheology of suspensions of prolate particles from measured. A generalized equation for rheology of emulsions and suspensions. Monodisperse colloidal hard sphere suspensions have been studied thoroughly for the case. Ii suspensions, emulsions and foams pier luca maffettone, francesco greco encyclopedia of life support systems eolss the actual particle dimension is irrelevant, and all macroscopic observables in the dilute case will only depend on the low solid volume fraction. It applies to substances which have a complex structure, including muds, sludges, suspensions, polymers, many foods, bodily. Rheology of concentrated suspensions of viscoelastic. Feb 26, 2018 rheology is the study and control of the flow properties1,2.
The emulsion showed a pseudoplastic flow whereas the suspension exhibited a plastic profile. The rheology of these dense suspensions can be approached via a diversity of approaches that the paper introduces successively. The effect of added solids to an emulsion is fully treated, and its relation to a bimodel system is. Surface avg particle diameter of internal phase was determined by microscope. An important challenge then is to link the microscopic singleparticle modulus directly to the macroscopic suspension rheology. In the absence of inertia, emulsions display a nonnewtonian rheology with positive first and negative second normal stress differences. Rheology and structure of emulsions and suspensions request pdf. Rheology of emulsions performance of the emulsion depends on flow properties removal of an emulsion from a bottle or tube flow of an emulsion through a hypodermic needle. Thixotropy is useful in the formulation of pharmaceutical suspensions and emulsions. Examples of suspensions include both natural and manmade materials for instance, ink as a suspension of pigments of dyes of typically 5 10. Rheology of dense granular suspensions journal of fluid. A basic introduction to rheology rheology and viscosity introduction rheometry refers to the experimental technique used to determine the rheological properties of materials. Hubbe, a pegah tayeb, a michael joyce, a preeti tyagi, a margaret kehoe, a,b katarina dimicmisic, c and lokendra pal a. This site is like a library, use search box in the widget to get ebook that you want.
The mixture of particles and fluid can be seen as a fluid with effective rheological properties but also as a twophase system wherein the fluid and particles can experience relative motion. Many pharmaceutical products are produced in the form of a suspension. Elasticities of attractive and repulsive emulsions differ below random close packing but are similar above it. Pdf a generalized equation for rheology of emulsions and. Understanding rheological properties of suspensions and how particle characteristics are controlling factors given the complementary range of materials characterization techniques we have here at malvern, the measurement of dispersed systems from suspensions, emulsions and foams, to pastes and gels is something that we are very familiar. Rheology is the study and control of the flow properties1,2. Increasing the zeroshear viscosity of the continuous phase of an emulsion or suspension is a popular method of increasing physical stability. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Coarse dispersions suspensions emulsions suspensions a pharmaceutical suspension is a coarse dispersion in which insoluble solid particles are dispersed in a liquid medium. Rheology and structure of emulsions and suspensions. The elastic modulus of individual oilfilled microgel particles will influence the bulk modulus of the microgel suspension. The laos analysis of hardsphere suspensions provides useful guidance for understanding the response of related, but more complex, materials such as gels, clay dispersions, and emulsions. Colloid rheology emulsions, foams, and suspensions wiley.
Models for the interpretation of rheological results. The rheology of suspensions of solid particles proceedings of the. Note that in all cases the terms oil and water are used in a broad sense, i. Rheology testing can be used as a rapid test for suspension stability, by looking at zero shear viscosity characteristics to look at sedimentation velocity. If the material is an ideal elastic solid, then the sample stress is pro.
The suspensions with nanoparticles are represented by suspensions of silica with concentrations from 1 to 4%. These multiparticle systems are subjected to a steady straining flow at low reynolds number. Instability of emulsions under stress conditions can be related to normal shelf life. It is usually caused by large velocity gradients in a thin region adjacent to the wall.
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