Emulsions are liquid-in-liquid dispersions where one liquid is dispersed as droplets in another liquid. They can be formed through mechanical comminution, which uses mechanical energy like stirring to break up one liquid into droplets in another, or through condensation methods involving thermodynamics. Key factors that influence emulsion formation and properties include the components, volume ratio, viscosity, additives, energy input, and temperature. Emulsifiers are used to aid formation and stabilize emulsions. Ultrasound and membrane emulsification are alternative comminution techniques. Particles can also stabilize emulsions through attachment at fluid-fluid interfaces.
This document provides information on emulsions and suspensions. It defines emulsions as dispersions with one liquid dispersed in another immiscible liquid, stabilized by an emulsifying agent. Emulsions are classified based on the dispersed and continuous phases. Suspensions are heterogeneous mixtures where particles settle out over time. Key factors that affect sedimentation rates in suspensions are described by Stokes' equation. Common emulsifying agents and suspending agents used in pharmaceutical formulations are also outlined.
Emulsion formation, stability, and rheologyAudrey Zahra
This document discusses emulsions, which are mixtures of two immiscible liquids where one liquid is dispersed as droplets in the other. There are different types of emulsions classified by the dispersed and continuous phases. Emulsions can be stabilized through the use of emulsifiers like surfactants and particles. Over time, emulsions may break down through processes like creaming, flocculation, coalescence, and Ostwald ripening. The selection of emulsifiers depends on properties like their hydrophilic-lipophilic balance number to match the oils being emulsified.
Nanoemulsion formation, stability and applicationsAshish Gadhave
This document summarizes nanoemulsions, which are kinetically stable emulsions with droplet sizes between 20-200 nm. It discusses their formation using high-energy methods like high-pressure homogenization and ultrasound, as well as low-energy methods like phase inversion temperature. The main instability mechanism for nanoemulsions is Ostwald ripening, where smaller droplets dissolve into a continuous phase. Applications described include use in pharmaceuticals for ocular, nasal, and other drug delivery due to improved absorption and stability compared to traditional emulsions. Nanoemulsion polymerization is also discussed as a technological application.
Suspension Formulation Overview For Formulators and Development ScientistsJim McElroy
This document discusses suspension formulations. Suspensions have a dispersed solid phase and a dispersion medium that can be solid, liquid, or gas. Particle interactions can be controlled through electrostatic or steric repulsive forces using formulation techniques. Forces like van der Waals attractions cannot be controlled. Structured vehicles use shear thinning polymers and clays to create suspensions that are semi-solid at rest but fluid with shaking, preventing settling. Flocculation uses electrolytes or polymers to reduce repulsive forces and promote particle aggregation and settling.
Membrane separation processes have been widely used for wastewater treatment due to their advantages over conventional processes. Key membrane processes for wastewater treatment include microfiltration, ultrafiltration, nanofiltration, reverse osmosis, and membrane bioreactors. These processes provide high quality treated water with low capital and operating costs due to their compact size and ability to automate. However, membrane fouling remains a challenge that can reduce membrane performance over time.
Rheology is the study of deformation and flow of matter. There are several types of rheological properties including stress, viscosity, viscoelastic modulus, creep, and relaxation times. Rheology is important in manufacturing pharmaceutical dosage forms and applications like ointments, syrups, suspensions, and emulsions where rheological properties influence acceptability, bioavailability, and handling. Materials can exhibit Newtonian, plastic, pseudo-plastic, or dilatant flow depending on the relationship between shear stress and shear rate. Viscometers are used to determine viscosity and classify fluids as Newtonian or non-Newtonian.
Suspensions are finely divided drugs dispersed in a liquid vehicle. They can be stabilized through electrostatic, steric, or hydration repulsive forces between particles. Emulsions are dispersions of one liquid in another, stabilized by surfactants. Key parameters that impact stability include choice of emulsifier, phase ratio, manufacturing method, and temperature during processing and storage. Different types of suspensions and emulsions exist for various dosage forms. Understanding colloid science principles is important for developing stable formulations.
This document discusses different types of suspensions including flocculated and structured vehicle suspensions. It defines key terms like electrostatic repulsive force, steric repulsive force, and van der Waals forces that influence particle interactions. Methods for controlling these interparticle forces through formulation are presented for flocculating particles and producing shear thinning structured vehicles. Examples of adjusting surface charge and adding polymers or clays are given. Properties of flocculated and structured vehicle suspensions are compared.
This document provides information on emulsions and suspensions. It defines emulsions as dispersions with one liquid dispersed in another immiscible liquid, stabilized by an emulsifying agent. Emulsions are classified based on the dispersed and continuous phases. Suspensions are heterogeneous mixtures where particles settle out over time. Key factors that affect sedimentation rates in suspensions are described by Stokes' equation. Common emulsifying agents and suspending agents used in pharmaceutical formulations are also outlined.
Emulsion formation, stability, and rheologyAudrey Zahra
This document discusses emulsions, which are mixtures of two immiscible liquids where one liquid is dispersed as droplets in the other. There are different types of emulsions classified by the dispersed and continuous phases. Emulsions can be stabilized through the use of emulsifiers like surfactants and particles. Over time, emulsions may break down through processes like creaming, flocculation, coalescence, and Ostwald ripening. The selection of emulsifiers depends on properties like their hydrophilic-lipophilic balance number to match the oils being emulsified.
Nanoemulsion formation, stability and applicationsAshish Gadhave
This document summarizes nanoemulsions, which are kinetically stable emulsions with droplet sizes between 20-200 nm. It discusses their formation using high-energy methods like high-pressure homogenization and ultrasound, as well as low-energy methods like phase inversion temperature. The main instability mechanism for nanoemulsions is Ostwald ripening, where smaller droplets dissolve into a continuous phase. Applications described include use in pharmaceuticals for ocular, nasal, and other drug delivery due to improved absorption and stability compared to traditional emulsions. Nanoemulsion polymerization is also discussed as a technological application.
Suspension Formulation Overview For Formulators and Development ScientistsJim McElroy
This document discusses suspension formulations. Suspensions have a dispersed solid phase and a dispersion medium that can be solid, liquid, or gas. Particle interactions can be controlled through electrostatic or steric repulsive forces using formulation techniques. Forces like van der Waals attractions cannot be controlled. Structured vehicles use shear thinning polymers and clays to create suspensions that are semi-solid at rest but fluid with shaking, preventing settling. Flocculation uses electrolytes or polymers to reduce repulsive forces and promote particle aggregation and settling.
Membrane separation processes have been widely used for wastewater treatment due to their advantages over conventional processes. Key membrane processes for wastewater treatment include microfiltration, ultrafiltration, nanofiltration, reverse osmosis, and membrane bioreactors. These processes provide high quality treated water with low capital and operating costs due to their compact size and ability to automate. However, membrane fouling remains a challenge that can reduce membrane performance over time.
Rheology is the study of deformation and flow of matter. There are several types of rheological properties including stress, viscosity, viscoelastic modulus, creep, and relaxation times. Rheology is important in manufacturing pharmaceutical dosage forms and applications like ointments, syrups, suspensions, and emulsions where rheological properties influence acceptability, bioavailability, and handling. Materials can exhibit Newtonian, plastic, pseudo-plastic, or dilatant flow depending on the relationship between shear stress and shear rate. Viscometers are used to determine viscosity and classify fluids as Newtonian or non-Newtonian.
Suspensions are finely divided drugs dispersed in a liquid vehicle. They can be stabilized through electrostatic, steric, or hydration repulsive forces between particles. Emulsions are dispersions of one liquid in another, stabilized by surfactants. Key parameters that impact stability include choice of emulsifier, phase ratio, manufacturing method, and temperature during processing and storage. Different types of suspensions and emulsions exist for various dosage forms. Understanding colloid science principles is important for developing stable formulations.
This document discusses different types of suspensions including flocculated and structured vehicle suspensions. It defines key terms like electrostatic repulsive force, steric repulsive force, and van der Waals forces that influence particle interactions. Methods for controlling these interparticle forces through formulation are presented for flocculating particles and producing shear thinning structured vehicles. Examples of adjusting surface charge and adding polymers or clays are given. Properties of flocculated and structured vehicle suspensions are compared.
This document discusses rheology and viscosity. It defines rheology as the science of flow of fluids and deformation of solids under stress. Viscosity is a measure of a fluid's resistance to flow and is important in formulation of products like creams, ointments, and suspensions. The document describes different types of fluid flow based on viscosity, such as Newtonian, plastic, and pseudoplastic flow. It also discusses instruments used to measure viscosity like capillary, falling sphere, cup and bob, and cone and plate viscometers. Thixotropy, where the viscosity of a fluid decreases under shear stress over time, is also covered.
This document discusses rheology, which is the science describing the flow and deformation of matter under stress. It defines key terms like viscosity, shear stress, shear rate, and classifies fluids as Newtonian or non-Newtonian based on their relationship between shear stress and shear rate. Newtonian fluids have a constant viscosity regardless of shear rate, while non-Newtonian fluids have variable viscosity. Plastic, pseudoplastic, and dilatant behaviors are described for non-Newtonian fluids. Thixotropy, which is a time-dependent decrease and recovery of viscosity under shear, is also discussed. The document concludes by explaining the operation and calibration of common viscometers.
This is an article on viscosity. It compares dynamic, absolute and kinematic viscosities, as well as their units. It is detailed and very good reading.
Homogenization is a unit operation that uses homogenizers to reduce the size of droplets in liquid-liquid dispersions. The key homogenization methods discussed are high pressure homogenization, colloid mills, high shear dispersers, ultrasonic homogenizers, and membrane homogenizers. The document outlines the operating principles of each type of homogenizer and the important process parameters that influence droplet size, such as energy density, emulsifier properties, and viscosity ratios of the dispersed and continuous phases. Selecting the appropriate homogenizer depends on the desired emulsion characteristics and production conditions.
Methods of preparation of novel emulsionManali Parab
This document discusses various methods for preparing novel emulsion systems, including multiple emulsions, microemulsions, and nanoemulsions. It describes multiple emulsion as emulsions of emulsions containing an internal phase dispersed in an intermediate phase that is then dispersed in an external continuous phase. Various preparation techniques are outlined, including two-step emulsification, phase inversion, and membrane emulsification methods. Microemulsions are described as thermodynamically stable, transparent or translucent systems formed using surfactants and cosurfactants. Methods for microemulsion preparation include phase titration and spontaneous emulsification. Nanoemulsions are defined as oil-in-water emulsions with droplets between 50-100 nm prepared using
multiphase flow modeling and simulation ,Pouriya Niknam , UNIFIPouriya Niknam
This document discusses modeling and simulation of multiphase flows using computational fluid dynamics (CFD). It begins with definitions of multiphase flow and discusses important types including bubbly, droplet, particle-laden, and annular flows. The document then provides tips on multiphase simulation including choosing appropriate modeling approaches such as Lagrangian, Eulerian, or volume of fluid methods depending on the problem. It concludes with discussions of challenges such as convergence difficulties and appropriate solver settings and techniques to address these challenges.
Liquid liquid extraction and flocculationvikash_94
Liquid-liquid extraction and flocculation are separation processes discussed in the document. Liquid-liquid extraction involves using two immiscible liquids to separate components of a mixture based on their relative solubilities in each liquid. Factors like distribution coefficient, selectivity, and physical properties of solvents are considered when choosing extraction solvents. Common equipment used includes mixer-settlers, columns, and centrifuges. Applications include removing products/pollutants from aqueous streams and washing polar compounds from organics. Flocculation involves using chemicals to induce clumping/aggregation of suspended particles in liquids to aid separation.
Unit 3 introduction to fluid mechanics as per AKTU KME101TVivek Singh Chauhan
strictly following syllabus of KME 101T of AKTU for first yr 2021
fluid properties, bernoulli's equation with proof and numericals , pumps, turbine , hydraulic lift, continuity equation
Mayonnaise exhibits complex rheological behavior. Rheological tests show that mayonnaise behaves as a viscoelastic solid in the linear viscoelastic region and yields at higher strains. It displays shear thinning behavior, where viscosity decreases with increasing shear rate. Mayonnaise also shows slight thixotropic properties, with minor hysteresis in dynamic strain sweeps at different frequencies. Temperature variations between 15-40°C do not significantly impact its viscosity.
A Brief Review Of Reverse Osmosis Membrane TechnologyTodd Turner
The document provides an overview of reverse osmosis membrane technology. It discusses how early studies in the 1700s led to the development of reverse osmosis as a separation process in the late 1950s. Major advances occurred in the 1960s with the creation of asymmetric cellulose acetate membranes, which had higher water fluxes and separations, making reverse osmosis practical. Since then, new thin-film composite membranes have been developed that can operate under wider conditions and have improved performance. Reverse osmosis has many applications and has experienced significant commercial growth.
The document provides an overview of microemulsions including their basic principles, formulation, and evaluation. It defines microemulsions as thermodynamically stable dispersions of oil and water stabilized by surfactants and sometimes cosurfactants. The document discusses various theories of microemulsion formation and the role of the main components - oil, surfactant, and cosurfactant. It also describes methods for preparing and characterizing microemulsions and techniques for evaluating parameters like particle size, drug release, and physical stability.
This document discusses pharmaceutical calculations including molarity, molality, and percentage concentration. It then covers topics related to emulsions including HLB value, emulsion types (O/W and W/O), emulsion stability testing, and factors that can cause emulsion instability such as creaming, flocculation, coalescence, and phase inversion. Specific examples are provided to illustrate pharmaceutical calculations for molarity and molality. Testing methods are also described for determining emulsion type using staining, fluorescence, and wetting of filter paper.
1. An emulsion is a mixture of two immiscible liquids, where one liquid is dispersed as globules in the other liquid.
2. Emulsions are thermodynamically unstable and require an emulsifying agent to stabilize the globules and prevent separation.
3. The key types of emulsions are oil-in-water and water-in-oil emulsions, as well as multiple emulsions containing both oil and water phases. Microemulsions are transparent, thermodynamically stable mixtures of oil, water and surfactants.
This document provides an overview of liposomes. It begins with an introduction describing liposomes as concentric bilayer vesicles composed mainly of phospholipids and cholesterol. It then covers the mechanism of liposome formation, classifications, biological fate, preparation methods, characterization techniques, advantages and disadvantages, and applications. Preparation methods discussed include physical dispersion, solvent dispersion, detergent solubilization, and various size reduction/increase techniques. Characterization includes assessing size, shape, lamellarity, surface charge, drug release, and encapsulation efficiency using tools like microscopy, NMR, and chromatography.
Multiple emulsions are complex systems that contain both water-in-oil (W/O) and oil-in-water (O/W) emulsions. They are thermodynamically unstable and require a combination of hydrophilic and hydrophobic surfactants to stabilize them. Common types include W/O/W and O/W/O emulsions. Multiple emulsions can prolong the release of active ingredients and have applications in controlled drug delivery, targeted delivery, and more. They are prepared using techniques like solvent evaporation or double emulsification and provide a novel carrier system for drugs, cosmetics, and other agents.
Rheology is the science that studies the flow and deformation of matter, especially fluids and semisolids, under stress. The document discusses various rheological concepts including viscosity, Newtonian and non-Newtonian flow, plastic flow, pseudoplastic flow, dilatant flow, thixotropy, and anti-thixotropy. It provides examples of different rheological behaviors exhibited by pharmaceutical formulations like suspensions, emulsions, and gels. Various viscometers used to characterize the rheological properties of such formulations are also described.
Microemulsions are thermodynamically stable transparent dispersions of nanometer-sized droplets of one liquid within another liquid, stabilized by surfactants and sometimes co-surfactants. They can solubilize both aqueous and oil-soluble compounds and have properties like ultralow interfacial tension. Microemulsions are characterized using techniques like scattering, NMR, electron microscopy, and by measuring interfacial tension, electrical conductivity, and viscosity. They have advantages like increased drug absorption and bioavailability and can be used for oral, topical, ocular, pulmonary, and parenteral delivery applications.
Determination of the molecular weight of high polyvinyl alcohol (pva) by visc...PRAVIN SINGARE
This presentation is based on demonstration on the Determination of the molecular weight of high polyvinyl alcohol (pva) by viscosity method. The presentation is made for Undergraduate Chemistry Students of Mumbai University
Heat is generated during fermentation that must be controlled. Common heat transfer configurations for bioreactors include jacketed vessels, internal coils, and external heat exchangers. External heat exchangers are best for heat transfer but require careful control of sterility and oxygen transfer. Internal coils can interfere with mixing and cleaning. Mass transfer in fermentation involves the diffusion of gases like oxygen across phase boundaries according to Fick's law and two-film theory. Downstream processing after fermentation includes steps like filtration, centrifugation, chromatography, and crystallization to isolate and purify products.
This document discusses rheology and viscosity. It defines rheology as the science of flow of fluids and deformation of solids under stress. Viscosity is a measure of a fluid's resistance to flow and is important in formulation of products like creams, ointments, and suspensions. The document describes different types of fluid flow based on viscosity, such as Newtonian, plastic, and pseudoplastic flow. It also discusses instruments used to measure viscosity like capillary, falling sphere, cup and bob, and cone and plate viscometers. Thixotropy, where the viscosity of a fluid decreases under shear stress over time, is also covered.
This document discusses rheology, which is the science describing the flow and deformation of matter under stress. It defines key terms like viscosity, shear stress, shear rate, and classifies fluids as Newtonian or non-Newtonian based on their relationship between shear stress and shear rate. Newtonian fluids have a constant viscosity regardless of shear rate, while non-Newtonian fluids have variable viscosity. Plastic, pseudoplastic, and dilatant behaviors are described for non-Newtonian fluids. Thixotropy, which is a time-dependent decrease and recovery of viscosity under shear, is also discussed. The document concludes by explaining the operation and calibration of common viscometers.
This is an article on viscosity. It compares dynamic, absolute and kinematic viscosities, as well as their units. It is detailed and very good reading.
Homogenization is a unit operation that uses homogenizers to reduce the size of droplets in liquid-liquid dispersions. The key homogenization methods discussed are high pressure homogenization, colloid mills, high shear dispersers, ultrasonic homogenizers, and membrane homogenizers. The document outlines the operating principles of each type of homogenizer and the important process parameters that influence droplet size, such as energy density, emulsifier properties, and viscosity ratios of the dispersed and continuous phases. Selecting the appropriate homogenizer depends on the desired emulsion characteristics and production conditions.
Methods of preparation of novel emulsionManali Parab
This document discusses various methods for preparing novel emulsion systems, including multiple emulsions, microemulsions, and nanoemulsions. It describes multiple emulsion as emulsions of emulsions containing an internal phase dispersed in an intermediate phase that is then dispersed in an external continuous phase. Various preparation techniques are outlined, including two-step emulsification, phase inversion, and membrane emulsification methods. Microemulsions are described as thermodynamically stable, transparent or translucent systems formed using surfactants and cosurfactants. Methods for microemulsion preparation include phase titration and spontaneous emulsification. Nanoemulsions are defined as oil-in-water emulsions with droplets between 50-100 nm prepared using
multiphase flow modeling and simulation ,Pouriya Niknam , UNIFIPouriya Niknam
This document discusses modeling and simulation of multiphase flows using computational fluid dynamics (CFD). It begins with definitions of multiphase flow and discusses important types including bubbly, droplet, particle-laden, and annular flows. The document then provides tips on multiphase simulation including choosing appropriate modeling approaches such as Lagrangian, Eulerian, or volume of fluid methods depending on the problem. It concludes with discussions of challenges such as convergence difficulties and appropriate solver settings and techniques to address these challenges.
Liquid liquid extraction and flocculationvikash_94
Liquid-liquid extraction and flocculation are separation processes discussed in the document. Liquid-liquid extraction involves using two immiscible liquids to separate components of a mixture based on their relative solubilities in each liquid. Factors like distribution coefficient, selectivity, and physical properties of solvents are considered when choosing extraction solvents. Common equipment used includes mixer-settlers, columns, and centrifuges. Applications include removing products/pollutants from aqueous streams and washing polar compounds from organics. Flocculation involves using chemicals to induce clumping/aggregation of suspended particles in liquids to aid separation.
Unit 3 introduction to fluid mechanics as per AKTU KME101TVivek Singh Chauhan
strictly following syllabus of KME 101T of AKTU for first yr 2021
fluid properties, bernoulli's equation with proof and numericals , pumps, turbine , hydraulic lift, continuity equation
Mayonnaise exhibits complex rheological behavior. Rheological tests show that mayonnaise behaves as a viscoelastic solid in the linear viscoelastic region and yields at higher strains. It displays shear thinning behavior, where viscosity decreases with increasing shear rate. Mayonnaise also shows slight thixotropic properties, with minor hysteresis in dynamic strain sweeps at different frequencies. Temperature variations between 15-40°C do not significantly impact its viscosity.
A Brief Review Of Reverse Osmosis Membrane TechnologyTodd Turner
The document provides an overview of reverse osmosis membrane technology. It discusses how early studies in the 1700s led to the development of reverse osmosis as a separation process in the late 1950s. Major advances occurred in the 1960s with the creation of asymmetric cellulose acetate membranes, which had higher water fluxes and separations, making reverse osmosis practical. Since then, new thin-film composite membranes have been developed that can operate under wider conditions and have improved performance. Reverse osmosis has many applications and has experienced significant commercial growth.
The document provides an overview of microemulsions including their basic principles, formulation, and evaluation. It defines microemulsions as thermodynamically stable dispersions of oil and water stabilized by surfactants and sometimes cosurfactants. The document discusses various theories of microemulsion formation and the role of the main components - oil, surfactant, and cosurfactant. It also describes methods for preparing and characterizing microemulsions and techniques for evaluating parameters like particle size, drug release, and physical stability.
This document discusses pharmaceutical calculations including molarity, molality, and percentage concentration. It then covers topics related to emulsions including HLB value, emulsion types (O/W and W/O), emulsion stability testing, and factors that can cause emulsion instability such as creaming, flocculation, coalescence, and phase inversion. Specific examples are provided to illustrate pharmaceutical calculations for molarity and molality. Testing methods are also described for determining emulsion type using staining, fluorescence, and wetting of filter paper.
1. An emulsion is a mixture of two immiscible liquids, where one liquid is dispersed as globules in the other liquid.
2. Emulsions are thermodynamically unstable and require an emulsifying agent to stabilize the globules and prevent separation.
3. The key types of emulsions are oil-in-water and water-in-oil emulsions, as well as multiple emulsions containing both oil and water phases. Microemulsions are transparent, thermodynamically stable mixtures of oil, water and surfactants.
This document provides an overview of liposomes. It begins with an introduction describing liposomes as concentric bilayer vesicles composed mainly of phospholipids and cholesterol. It then covers the mechanism of liposome formation, classifications, biological fate, preparation methods, characterization techniques, advantages and disadvantages, and applications. Preparation methods discussed include physical dispersion, solvent dispersion, detergent solubilization, and various size reduction/increase techniques. Characterization includes assessing size, shape, lamellarity, surface charge, drug release, and encapsulation efficiency using tools like microscopy, NMR, and chromatography.
Multiple emulsions are complex systems that contain both water-in-oil (W/O) and oil-in-water (O/W) emulsions. They are thermodynamically unstable and require a combination of hydrophilic and hydrophobic surfactants to stabilize them. Common types include W/O/W and O/W/O emulsions. Multiple emulsions can prolong the release of active ingredients and have applications in controlled drug delivery, targeted delivery, and more. They are prepared using techniques like solvent evaporation or double emulsification and provide a novel carrier system for drugs, cosmetics, and other agents.
Rheology is the science that studies the flow and deformation of matter, especially fluids and semisolids, under stress. The document discusses various rheological concepts including viscosity, Newtonian and non-Newtonian flow, plastic flow, pseudoplastic flow, dilatant flow, thixotropy, and anti-thixotropy. It provides examples of different rheological behaviors exhibited by pharmaceutical formulations like suspensions, emulsions, and gels. Various viscometers used to characterize the rheological properties of such formulations are also described.
Microemulsions are thermodynamically stable transparent dispersions of nanometer-sized droplets of one liquid within another liquid, stabilized by surfactants and sometimes co-surfactants. They can solubilize both aqueous and oil-soluble compounds and have properties like ultralow interfacial tension. Microemulsions are characterized using techniques like scattering, NMR, electron microscopy, and by measuring interfacial tension, electrical conductivity, and viscosity. They have advantages like increased drug absorption and bioavailability and can be used for oral, topical, ocular, pulmonary, and parenteral delivery applications.
Determination of the molecular weight of high polyvinyl alcohol (pva) by visc...PRAVIN SINGARE
This presentation is based on demonstration on the Determination of the molecular weight of high polyvinyl alcohol (pva) by viscosity method. The presentation is made for Undergraduate Chemistry Students of Mumbai University
Heat is generated during fermentation that must be controlled. Common heat transfer configurations for bioreactors include jacketed vessels, internal coils, and external heat exchangers. External heat exchangers are best for heat transfer but require careful control of sterility and oxygen transfer. Internal coils can interfere with mixing and cleaning. Mass transfer in fermentation involves the diffusion of gases like oxygen across phase boundaries according to Fick's law and two-film theory. Downstream processing after fermentation includes steps like filtration, centrifugation, chromatography, and crystallization to isolate and purify products.
Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
Cell Therapy Expansion and Challenges in Autoimmune DiseaseHealth Advances
There is increasing confidence that cell therapies will soon play a role in the treatment of autoimmune disorders, but the extent of this impact remains to be seen. Early readouts on autologous CAR-Ts in lupus are encouraging, but manufacturing and cost limitations are likely to restrict access to highly refractory patients. Allogeneic CAR-Ts have the potential to broaden access to earlier lines of treatment due to their inherent cost benefits, however they will need to demonstrate comparable or improved efficacy to established modalities.
In addition to infrastructure and capacity constraints, CAR-Ts face a very different risk-benefit dynamic in autoimmune compared to oncology, highlighting the need for tolerable therapies with low adverse event risk. CAR-NK and Treg-based therapies are also being developed in certain autoimmune disorders and may demonstrate favorable safety profiles. Several novel non-cell therapies such as bispecific antibodies, nanobodies, and RNAi drugs, may also offer future alternative competitive solutions with variable value propositions.
Widespread adoption of cell therapies will not only require strong efficacy and safety data, but also adapted pricing and access strategies. At oncology-based price points, CAR-Ts are unlikely to achieve broad market access in autoimmune disorders, with eligible patient populations that are potentially orders of magnitude greater than the number of currently addressable cancer patients. Developers have made strides towards reducing cell therapy COGS while improving manufacturing efficiency, but payors will inevitably restrict access until more sustainable pricing is achieved.
Despite these headwinds, industry leaders and investors remain confident that cell therapies are poised to address significant unmet need in patients suffering from autoimmune disorders. However, the extent of this impact on the treatment landscape remains to be seen, as the industry rapidly approaches an inflection point.
Rasamanikya is a excellent preparation in the field of Rasashastra, it is used in various Kushtha Roga, Shwasa, Vicharchika, Bhagandara, Vatarakta, and Phiranga Roga. In this article Preparation& Comparative analytical profile for both Formulationon i.e Rasamanikya prepared by Kushmanda swarasa & Churnodhaka Shodita Haratala. The study aims to provide insights into the comparative efficacy and analytical aspects of these formulations for enhanced therapeutic outcomes.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
ABDOMINAL TRAUMA in pediatrics part one.drhasanrajab
Abdominal trauma in pediatrics refers to injuries or damage to the abdominal organs in children. It can occur due to various causes such as falls, motor vehicle accidents, sports-related injuries, and physical abuse. Children are more vulnerable to abdominal trauma due to their unique anatomical and physiological characteristics. Signs and symptoms include abdominal pain, tenderness, distension, vomiting, and signs of shock. Diagnosis involves physical examination, imaging studies, and laboratory tests. Management depends on the severity and may involve conservative treatment or surgical intervention. Prevention is crucial in reducing the incidence of abdominal trauma in children.
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by...Donc Test
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Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
1. Emulsions – Part 1
Definition
Preparation methods
(some) Properties
Klaus Tauer
MPI Colloids and Interfaces
Am Mühlenberg, D-14476 Golm, Germany
2. Dispersed Systems with Liquid
Continuous Phases*
Dispergere (Latin): to remove, to redistribute
Emulgere (Latin): to milk out
Suspendere (Latin): to keep in, to keep in floating
Dispersed phase
gas
liquid
solid
Technical term
foam
emulsion
sol, suspension
Example
meringue, whipped cream
milk, mayonnaise, butter
latex, paint, blood
* water as continuous phase and an organic dispersed phase or vice versa (inverse emulsions)
3. What is an Emulsion?
an emulsion is a liquid in liquid dispersion
a (polymer) solution is also a liquid
(polymer) solutions can form
emulsions
an emulsion droplet interface has at any point the same
interfacial tension (in contrast to many suspension particles)
sometimes emulsions are subdivided arbitrarily regarding
the droplet size (macro-, mini-, microemulsions) and hence
general aspects might be lost
4. Emulsification
comminution
(destruction)
mechanical energy or
pressure is doing the job
the most widely used
procedure (making a salad
dressing in the kitchen)
condensation
(construction)
thermodynamics
takes care
swelling of colloidal
systems such as
micelles or solid
(polymer) particles
with liquids
5. this relation is (possibly) the oldest topic in colloid chemistry and much more also the oldest
example of its practical application (pouring oil over water)
oil
water
mediator:
dishwashing liquid
emulsion
stirrer
oily phase
hydrophobe
water
hydrophile
surfactants
emulsifiers
stabilizers
mediator
Emulsification - Basics
6. Emulsion formation by comminution
9comminution power
9interfacial tension
9viscosity of both phases
9duration of the comminution
9degradation after comminution is stopped
Σ a process with high complexity
olive oil & water
Influenced by:
7. Comminution - Structure of the
Emulsion
Which liquid forms the dispersed phase and
which will be the continuous one?
influenced by the volume ratio of the liquids, the kind of the emulsifying agent,
and its concentration in strong connection with the temperature.
most important property of the emulsifying agent is its
solubility (in both phases) or in the case of the solid
stabilizers the wetting behavior of both liquids
? ?
Bancroft’s Rule (1912)
8. Tests for Identification of Emulsion Types:
• Dilution test: emulsion can be diluted only with external phase
• Dye test: water or oil soluble dyes
• CoCl2/filter paper test: filter paper impregnated with CoCl2
and dried (blue) changes to pink when o/w emulsion is
added
• Fluorescence: some oils fluoresce under UV light
• Conductivity: for ionic o/w emulsions
(o/w emulsions conduct electric current)
9. Action of Emulsifiers
main actions:
reducing the
interfacial tension
between the phases
forming a barrier
between the phases
10. Action of Emulsifiers
- promoting the formation
of an emulsion,
- making it easier to prepare,
- producing finer droplet size,
- aiding stability to the dispersed
state
controlling the type of emulsion that is
to be formed: oil in water (O/W) or
water in oil (W/O)
11. ∆W is the free energy of the interface and corresponds to the
reversible work brought permanently into the system during the
emulsification process .
This makes an emulsion very prone to coalescence processes
which lead to a decrease in ∆A and subsequently in ∆W.
The conclusion is straightforward that ultimate stability against
coalescence processes is only achieved if s approaches zero.
A
W ∆
⋅
σ
=
∆
The increase in the energy of an emulsion compared to the non-
emulsified components is equal to ∆W.
This amount of energy can be considered as a measure of the
thermodynamic instability of an emulsion.
Work of Emulsion Formation:
12. Preparation of Emulsions by Comminution
input of mechanical energy by stirrers is the most important case
stirrers generate macro-eddies or macro-turbulences with a
characteristic length in the order of the stirrer diameter.
macro-eddies decompose into micro-eddies with a
characteristic length λ which is also called Kolmogorov length
micro-eddies are finally responsible for the energy transfer and
hence the breakage of the macroscopic phase
4
/
1
3
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
ε
ν
=
λ
λ relates to the kinematic viscosity of the solution
(ν) and the dissipation rate (ε) which is the power
input by the stirrer (P) per mass (m)
13. The Comminution Progress
D
time
ε / W
B
C
A
as soon as the shear exerted by the turbulent
micro-eddies on the droplet interface exceeds
the cohesive forces of the liquids in the drops
they split up to smaller units
cleavage occurs as long as a balance
between the external stress and the internal
stress is reached
( )
b
a r
r
P
+
σ
=
∆
14. The Comminution Process (1)
a - STR – stirred tank reactor consisting of a cylindrical vessel (diameter 30 cm, volume 21.2 l) with a
flat bottom and four symmetrical baffles and a six blade disc impeller with a diameter of 10 cm
b - Screw loop reactor, volume of the dispersing zone about 64 ml and reactor volume 1.67 l
c - Ultra turrax T50 from IKA with a dispersing tool type S50-G45F used in a cylindrical vessel with a
volume of 8 l
steady state DSD for different rotor / stator systems: φ = 0.1, 50 mM SDS
Ludwig, A., U. Flechtner, J. Prüss, H.-J. Warnecke, Formation of emulsions in a screw loop reactor,
Chem. Eng. Technol., 20, 149 - 161 (1997)
)
(
)
(
10
)
(
10
5 3
2
1
2
3
6 −
−
−
−
⋅
∆
⋅
⋅
=
⋅
⋅
=
∆ m
m
A
m
N
m
J
W
3
2
8
10
5 −
⋅
⋅
=
∆ m
m
A nm
D 3
.
1
=
experimental
values
Machine Conditions for WV = 5⋅106
J m-3
Maximum Dd in DSD
STR a)
n = 500 rpm, td = 60 min 60 – 70 µm
Screw loop b)
n = 4000 rpm, v = 350 l h-1
10 – 11 µm and 2 µm
Ultra turrax c)
n = 10.000 rpm, td = 2 min 10 – 11 µm and 2 µm
theory
15. Y.-F. Maa, C. Hsu J. Controlled Release 38, 219-228 (1996)
0,4 g/ml PMMA in MeCl2 in
a 0,2 g/ml BSA solution
(v:v = 10:2)
batch homogenizer
a steady state DSD is reached
The Comminution Process (2)
16. pluronics
soya oil, screw loop reactor
A. Ludwig, U. Flechtner, J. Prüss, H.-J. Warnecke
Chem. Eng. Technol. 20, 149-161 (1997)
SDS
H.+ M. Polat, S. Chander
AIChE Journal 45, 1866-1874 (1999)
stirred tank, turbine-type stirrer
self preserving
DSD
The Comminution Process (3)
17. viscoelastic force of the dispersed phase
emulsification of an aqueous bovine serum albumin solution in
dichloromethane containing poly(methyl methacrylate) (PMMA) as
stabilizer with different agitation machines
solution viscosity is a direct measure of the viscoelastic force
The Comminution Process (4)
Agitation machine Relation
Rotor stator homogenizer 43
.
0
c
11
.
0
d
d
D −
η
η
∝
Baffled mixed tank 42
.
0
c
22
.
0
d
d
D −
η
η
∝
Static Mixture 56
.
0
c
004
.
0
d
d
D −
η
η
∝
viscosity of the dispersed
phase (ηd) and of the
continuous phase (ηc)
increasing ηc means
increasing shear stress
at a given comminution
energy
18. Comminution by Ultrasound
(special kind of mechanical energy input )
Ultrasound means the application of
high frequency vibrations. In a first
step larger drops (Dd » 100 µm) are
produced in a way that instabilities
of interfacial waves will be
enhanced leading finally to the
crushing. These drops are
subsequently fragmented into
smaller ones by acoustic cavitation.
The use of ultrasound in
emulsification processes is much
more efficient than the application of
rotor / stator systems.
Physical and chemical
effects of cavitation
[K. S. Suslick, University of Illinois, USA]
The energy of the
ultrasonic wave is
concentrated into highly
localized temperature
and pressure “hot spots”
19. [K. S. Suslick, University of Illinois, USA]
action
of
ultrasound
20. Acoustical energy is mechanical energy i.e. it is not absorbed by molecules.
Ultrasound is transmitted through a medium via pressure waves by inducing
vibrational motion of the molecules which alternately compress and stretch
the molecular structure of the medium due to a time-varying pressure.
Therefore, the distance among the molecules varies as the molecules
oscillate around their mean position.
If the intensity of ultrasound in a liquid is increased, a point is reached at
which the intramolecular forces are not able to hold the molecular structure
intact. Consequently, it breaks down and a cavity is formed. This cavity is
called cavitation bubble as this process is called cavitation and the point
where it starts cavitation threshold.
A bubble responds to the sound field in the liquid by expanding and
contracting, i.e. it is excited by a time-varying pressure.
Two forms of cavitation are known: stable and transient. Stable cavitation
means that the bubbles oscillate around their equilibrium position over
several refraction/compression cycles. While transient cavitation, the
bubbles grow over one (sometimes two or three) acoustic cycles to double
their initial size and finally collapse violently.
Cavitation
21. [K. S. Suslick, University of Illinois, USA]
comminution and reaction
22. Comminution by Ultrasound - A Practical Example 1
(25 % kerosene volume fraction; total volume of 80 ml) with a
polyethoxylated (20EO) sorbitan monostearate surfactant (interfacial tension
kerosene to water 9.5 mN m-1
Abismail, B., J. P. Canselier, A. M. Wilhelm, H. Delmas, C. Gourdon, Emulsification by ultrasound. drop size
distribution and stability, Ultrasonics Sonochemistry, 6, 75 - 83 (1999)
ultrasound horn (20 kHz, 130 W)
ultra turrax (n = 10.000 rpm,
170 W)
surfactant
concentration:
surfactant
concentration:
24. What will happen if an emulsion which was prepared by a
certain comminution technique is exposed to a different
shear stress ???
Note, the shear stress is the product of shear rate and viscosity and hence it
combines emulsion properties with properties of the comminution technique.
Mason, T. G. and J. Bibette, Shear rupturing of droplets in complex fluids Langmuir, 13, 4600 - 4613 (1997)
shear stress
?
Consecutive emulsification
25. Shear Rupturing of Emulsion Droplets
Mason, T. G. and J. Bibette, Langmuir, 13, 4600 - 4613 (1997)
2. step (Couette)
1. step (STR)
The pre-emulsions consisted of
poly(dimethylsiloxane) oil (volume
fraction φ) in water stabilized with a
nonionic surfactant (nonylphenol with 7
ethylene oxide units (mass fraction with
respect to water C).
At shear rates larger than 10 s-1 in
the Couette flow the polydisperse
pre-emulsion starts to convert into
monodisperse ones.
26.
27. Shear Rupturing of Emulsion Droplets, practical examples
1
2
s
10 −
•
≈
γ
Mason, T. G. and J. Bibette, Langmuir, 13, 4600 - 4613 (1997)
10 s-1 in the Couette flow the
polydisperse pre-emulsion starts to
convert into monodisperse ones.
The dependence of the final droplet
size on the emulsifier concentration
is as expected: Dd decreases with
increasing C
but
Dd decreases with increasing volume
fraction of the organic phase
•
>
γ
Dd decreases with increasing volume fraction of the organic phase.
This is a remarkable result as it indicates fundamental differences in
the comminution mechanisms.
oil
surfactant
28.
29. Membrane Emulsification - Principle
This technique was first reported at the 1988 autumn conference of the Japanese Chemical
Engineering Society utilizing a micro-porous glass (MPG) membrane made of
CaO-Al2O3-B2O3-SiO2.
SPG info-material, Japan
30. Membrane Emulsification - Results
M
d D
f
D ⋅
=
f : 2 - 8
DM - pore diameter
Dd – droplet diameter
Continuous phase:
66.7 w% water
3 w% triethanolamine
0.3 w% sodium nipastat
Dispersed phase:
27 w% mineral oil
3 w% isosteric acid
Williams, R. A.; S. J. Peng, D. A. Wheeler, N. C. Morley, D. Taylor, M. Whalley and D. W. Houldsworth,
Controlled production of emulsions using a crossflow membrane Part II: industrial scale manufacture,
TransIChemE 76, 902 - 910 (1998)
Re > 4000 turbulent flow
31. Membrane Emulsification - more Results
membrane
monodispers drops
Oil phase: soy bean oil with 0.5 wt-% Span 80
Water phase: 1 wt-% NaCl solution
Membrane: hydrophobic SPG Dm = 2,56 µm;
∆P = 25 kPa
SPG info-material, Japan
32. Comminution - Summary
this emulsification process is influenced by various parameters:
- the volume phase ratio
- the viscosity of both phases
- the mutual solubility of both phases
- the kind and concentration of additives
- the stirrer as well as the vessel geometry
- the diminution energy and the power input
- thermodynamic changes during the emulsification
process (reactions, temperature).
33. Particles as Stabilizers -Pickering Emulsions (1)
any kind of particles: minerals
polymers
crucial is the wetting behavior:
contact angle
particle size
solids concentration
interparticular interaction
(R. Daniels)
W. Ramsden Proc. R. Soc. Lond. 72 (1904) 156-164
S. U. Pickering J. Chem. Soc. 91 (1907) 2001
34. Particles as Stabilizers -Pickering Emulsions (2)
Energy of attachment or removal of a particle to or from a
fluid-fluid interface (E) is not only related to the contact angle
(Θ) but also to the interfacial tension (γαβ). Small enough
particles - no effect of gravity. The sign inside the bracket is
negative for removal into the water phase, and positive for
removal into the oil phase.
If D~20 nm and γαβ~36 mN/m the particle is most strongly held
in the interface for Θ = 90° with E = 2750 kT. Either side of 90°, E
falls rapidly for 0 - 20° and 160 - 180° to less than 10 kT.
For Θ < 90° the particle is more hydrophilic and for Θ > 90 ° the
particle is more hydrophobic.
Note, E depends on the square of the particle size!
B. P. Binks Curr. Op. Coll. Interf. Sci. 7 (2002) 21-41
35. Particles as Stabilizers -Pickering Emulsions (3a)
Inorganic particles as stabilizers
technical of importance for: pharmaceutical and cosmetic products,
crude oil and oil recovery,
waste products in soils (O/W),
suspension polymerization of styrene
(with CaCO3, BaSO4, Ca5[(OH)|(PO4)3])
hydroxylapatite
O/W emulsion stabilized with TiO2-
particles
S. Wiesner, S. S. Biel, K. P. Wittern, U.
Hintze, R. Wepf Microscop. Microanal. 9
(2003) 510
backscattered electron (BSE) imaging
of cryo-fracture SEM
(high pressure frozen sample: -196 °C and 2200 bar)
36. D. A. Weitz Science 298 (2002) 1006-1009
„Colloidosomes“
Particles as Stabilizers -Pickering Emulsions (3b)
Latex particles as stabilizer
B.
P.
Binks,
S.
O.
Lumsdon
Langmuir
17
(2001)4540-4547
a 760 µm diameter hollow sphere
consisting of a monolayer of 7.9
µm monodisperse polystyrene
particles flocculated onto a
nitrogen bubble formed during
seeded emulsion polymerization
experiment aboard the space
shuttle orbiter Challenger (STS 7,
June 1983)
[J. W. Vanderhoff, O. Shaffer EPI Lehigh University,
Bethlehem,USA]
37. Multiple Emulsions (1)
Emulsifying an emulsion in another continuous phase to get either
W/O/W or O/W/O emulsions requires stabilizers with different HLB
(M. Akhtar)
secondary emulsifier
38. B. P. Binks Curr. Op. Coll. Interf. Sci. 7 (2002) 21-41
hydrophilic and hydrophobic
silica particles as stabilizer
Multiple Emulsions (2)
O/W:
Oil phase: soy bean oil with 1 wt-% PGCR
Water phase: 5 wt-% Na2PO4/KH2PO4 4/1
Membrane: hydrophobic SPG Dm = 0.36 µm;
∆P = 300 kPa
W/O/W:
O/W in 1wt-% aqueous Tween 20 + 0.5 wt-% NaCl
Membrane: hydrophilic SPG Dm = 2.8 µm;
∆P = 40 kPa
membra
ne
emulsific
ation
SPG info-material, Japan
39. Preparation of Emulsions by Condensation
Techniques
or
The Gentle Way to Make Emulsions
• condensation does not require mechanical energy except sometimes
ggentle stirring to avoid creaming or settling due to density differences
bbetween both phases
• mainly determined by thermodynamic principles
• swelling of preformed colloidal objects
• sometimes in the presence of emulsifying or swelling adjuvant
41. Microemulsions (2)
apparently a single phase
two phases
more surfactant than
dispersed phase
frequently surfactant plus
co-surfactant (alcohol)
complicated phase
diagrams
no direct contact
between both phases
42. Microemulsions (3)
comparing emulsions and microemulsions:
Helfrich free energy (HFE) introduced 1973
by W. Helfrich explains interface and
topological fluctuations involving the
interface curvatures c1, c2 and the
spontaneous interface curvature c0.
K and K are moduli and associated with
these fluctuations.
lower amount of surfactant
thermodynamically unstable
direct phase contact
interfacial tension 20-50 mN/m
turbid
higher amount of surfactant
thermodynamically stable
no direct phase contact
interfacial tension 10-4 mN/m
transparent
rule of thumb: high HLB is needed to prepare O/W
emulsions, low HLB is needed to produce W/O
emulsion and intermediate HLB gives µ-emulsion
stability of µ-emulsions:
44. Spontaneous Emulsification
This process obviously involves also the diffusion of the monomer through the
aqueous phase into the structures formed by the mixed surfactant system.
The synergistic action of the alcohol surfactant mixture results in a less
power demand for the emulsification (gentle stirring is enough) and an
enhanced droplet stability. This effect is called spontaneous emulsification and
its mechanism is still a matter of controversial discussion.
Dewald, R. C., L. H. Hart and W. F. Carroll, Jr., J. Polym. Sci.: Polym Chem. Ed., 22, 2923 – 2930
(1984)
Ugelstad, J., P. C. Mork and A. Berge, Vinyl chloride polymerization in Emulsion Polymerization
and Emulsion Polymers, (Eds. P. A. Lovell and M. S. El-Aasser), Wiley, Chichester, 1997
since 50 years: fatty alcohols (for instance lauryl alcohol) act as
emulsifying adjuvant for ammonium fatty acids
soaps during emulsion polymerizations [40]
soap : alcohol in a 2 : 1
stoichiometry
polymerizable miniemulsion
droplets are formed
45. Surfactant – Alcohol Mixtures
Patist, A.; T. Axelberd and D. O. Shah, J. Coll. Interf. Sci., 208, 259 - 265 (1998)
Jönsson, B., B. Lindman, K. Holmberg, and B. Kronberg, Surfactants and Polymers in
Aqueous Solution, Wiley, Chichester, 1998
Oh, S. G. , M. Jobalia and D. O. Shah, J. Coll. Interf. Sci., 155, 511 - 514 (1993)
surfactant alcohol mixtures possess a variety of exceptional
properties : highest packing density, lowest interfacial tension,
highest surface viscosity, minimum in droplet / bubble size, and
formation of the most stable microemulsions.
compound- 2
small amounts of a highly water-insoluble compound in the
monomer phase prevents the formation of a miniemulsion
importance of diffusion processes through the
aqueous phase for the spontaneous emulsification.
46. Swelling and Polymerization
latex particles
uptake of monomer
emulsion of swollen
latex particles
final latex
particle after
polymerization
promotion of swelling ???
shrinkage during
polymerization
1/3
mon
p d
pol
ρ
D = •D
ρ
⎛ ⎞
⎜ ⎟
⎜ ⎟
⎝ ⎠
47. Swelling – Some Theory
0
RT
v
P
RT
D
v
4
)
j
(
)
j
1
1
(
)
j
1
1
(
ln
1
sw
1
2
3
,
2
3
,
1
2
,
1
3
2
3
,
1
2
3
2
,
1
2
2
3
3
2
2
1
=
⋅
+
⋅
σ
⋅
+
χ
−
χ
+
χ
φ
⋅
φ
+
+
χ
⋅
φ
+
χ
⋅
φ
+
φ
−
+
φ
−
+
φ
J. Ugelstad, K.H. Kaggerud, F.K. Hansen, A. Berge Makromol. Chem. 180, 737-744 (1979
K. Tauer, H. Kaspar, M. Antonietti Coll. Polym. Sci. 278, 814-820 (2000)
1 - monomer
2 - oligomer / compound- 2
3 - polymer
j - degree of polymerization, c - interaction
parameter, f - volume fraction, v - partial
molar volume, D - equilibrium swollen
particle size, RT - thermal energy
swelling promoter
entropy promotes
swelling
48. Swelling – Some Examples
seed particles
emulsion droplets
(swollen particles)
1. chloro-decane
(promoter)
2. chloro-benzene
(oil)
J. Ugelstad, K.H. Kaggerud, F.K. Hansen, A. Berge Makromol. Chem. 180, 737-744 (1979
49. ⎥
⎦
⎤
⎢
⎣
⎡
φ
−
φ
ρ
⋅
+
φ
⋅
χ
+
φ
⋅
−
+
φ
−
−
=
⋅
⋅
⎟
⎠
⎞
⎜
⎝
⎛
+
γ
⋅
)
2
/
(
M
v
)
j
/
1
1
(
)
1
ln(
T
R
v
P
r
2
2
3
/
1
2
C
2
1
2
2
2
2
2
1
⎟
⎠
⎞
⎜
⎝
⎛ λ
⋅
+
⋅
γ
=
γ ∞
r
2
1
)
r
( 1
⎟
⎠
⎞
⎜
⎝
⎛ λ
⋅
+
⋅
χ
=
φ
χ ∞
r
3
1
)
,
r
( 2
2
2
2
2
2 036
.
0
311
.
0
431
.
0
)
( φ
⋅
−
φ
⋅
−
=
φ
χ∞
The factor (Z) is introduced taking into account the transition from the quasi
homogeneous microgel system in toluene over to the heterogeneous
aqueous systems of charged polystyrene in the presence of toluene. The
factor Z acts directly on P0. P0 represents the swelling pressure of chemically
identical bulk materials and P* can be considered as a modulus describing
the pressure increase with decreasing size of the sample.
r
P
P
P
*
0 +
=
Swelling of Latex Particles:
Coll. Polym. Sci. 278, 814-820 (2000)
50. influence of particle
surface chemistry
Swelling of Latex Particles: Experimental Results
Coll. Polym. Sci. 278, 814-820 (2000)
51. Swelling – Practical Meaning
monodispers latexes for
medical applications ;
e.g. „Dynabeads“
Distler
Ugelstad
Distler
in technical scale production
semibatch procedure with feeding a
monomer emulsion; normal swelling of
seed particles
~25·106 tons / y
(polymers worldwide)
52. see you next week:
a little (theory) on emulsion stability