Examine individual changes

'{{short description|Mixture of two or more liquids that are generally immiscible}} {{About|mixtures of liquids|the light-sensitive mixture used in photography|Photographic emulsion}} [[File:Emulsions.svg|frame|right| {{ordered list |list_style_type=upper-alpha |1=<!--A-->Two immiscible liquids, not yet emulsified |2=<!--B-->An emulsion of Phase II dispersed in Phase I |3=<!--C-->The unstable emulsion progressively separates |4=<!--D-->The [[surfactant]] (outline around particles) positions itself on the interfaces between Phase II and Phase I, stabilizing the emulsion }}]] An '''emulsion''' is a [[mixture]] of two or more [[liquid]]s that are normally [[immiscible]] (unmixable or unblendable). Emulsions are part of a more general class of two-phase systems of [[matter]] called [[colloid]]s. Although 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 liquid (the dispersed [[phase (matter)|phase]]) is [[dispersion (chemistry)|dispersed]] in the other (the continuous phase). Examples of emulsions include [[vinaigrette]]s, homogenized [[milk]], and some [[cutting fluid]]s for [[metal working]]. The word "emulsion" comes from the Latin mulgeo, mulgere "to milk",{{Specify|reason=What is the Latin word?|date=August 2017}} as milk is an emulsion of fat and water, along with other components. Two liquids can form different types of emulsions. As an example, oil and water can form, first, an oil-in-water emulsion, wherein the oil is the dispersed phase, and water is the dispersion medium. ([[Lipoproteins]], used by all complex living organisms, are one example of this.) Second, they can form a water-in-oil emulsion, wherein water is the dispersed phase and oil is the external phase. Multiple emulsions are also possible, including a "water-in-oil-in-water" emulsion and an "oil-in-water-in-oil" emulsion.<ref>{{cite journal|pmid=17076645 |year=2006 |author1=Khan |first1=A. Y. |title=Multiple emulsions: An overview |journal=Current Drug Delivery |volume=3 |issue=4 |pages=429–43 |last2=Talegaonkar |first2=S |last3=Iqbal |first3=Z |last4=Ahmed |first4=F. J. |last5=Khar |first5=R. K. |doi=10.2174/156720106778559056}}</ref> Emulsions, being liquids, do not exhibit a static internal structure. The droplets dispersed in the liquid matrix (called the “dispersion medium”) are usually assumed to be [[Probability distribution|statistically distributed]]. The term "emulsion" is also used to refer to the photo-sensitive side of [[photographic film]]. Such a [[photographic emulsion]] consists of [[silver halide]] colloidal particles dispersed in a [[gelatin]] matrix. [[Nuclear emulsion]]s are similar to photographic emulsions, except that they are used in particle physics to detect high-energy [[elementary particle]]s. ==Appearance and properties== {{Quote box |title =[[International Union of Pure and Applied Chemistry|IUPAC]] definition |quote = Fluid system in which liquid droplets are dispersed in a liquid. ''Note 1'': The definition is based on the definition in ref.<ref>{{cite book|title=Compendium of Chemical Terminology (The "Gold Book")|year=1997|publisher=[[Blackwell Scientific Publications]]|location=Oxford|author=IUPAC|chapter-url=http://goldbook.iupac.org/E02065.html|deadurl=bot: unknown|archiveurl=https://web.archive.org/web/20120310221658/http://goldbook.iupac.org/E02065.html|archivedate=2012-03-10|df=|doi=10.1351/goldbook.E02065|chapter=Emulsion|isbn=978-0-9678550-9-7}}</ref> ''Note 2'': The droplets may be amorphous, liquid-crystalline, or any<br/>mixture thereof. ''Note 3'': The diameters of the droplets constituting the ''[[Dispersion (chemistry)|dispersed phase]]''<br/>usually range from approximately 10 nm to 100 μm; i.e., the droplets<br/>may exceed the usual size limits for [[colloid]]al particles. ''Note 4'': An emulsion is termed an oil/water (o/w) emulsion if the<br/>dispersed phase is an organic material and the ''continuous phase'' is<br/>water or an aqueous solution and is termed water/oil (w/o) if the dispersed<br/>phase is water or an aqueous solution and the continuous phase is an<br/>organic liquid (an "oil"). ''Note 5'': A w/o emulsion is sometimes called an inverse emulsion.<br/>The term "inverse emulsion" is misleading, suggesting incorrectly that<br/>the emulsion has properties that are the opposite of those of an emulsion.<br/>Its use is, therefore, not recommended.<ref>{{cite journal|title=Terminology of polymers and polymerization processes in dispersed systems (IUPAC Recommendations 2011)|journal=[[Pure and Applied Chemistry]]|year=2011|volume=83|issue=12|pages=2229–2259|doi=10.1351/PAC-REC-10-06-03|last1=Slomkowski|first1=Stanislaw|last2=Alemán|first2=José V.|last3=Gilbert|first3=Robert G.|last4=Hess|first4=Michael|last5=Horie|first5=Kazuyuki|last6=Jones|first6=Richard G.|last7=Kubisa|first7=Przemyslaw|last8=Meisel|first8=Ingrid|last9=Mormann|first9=Werner|last10=Penczek|first10=Stanisław|last11=Stepto|first11=Robert F. T.}}</ref> }} Emulsions contain both a dispersed and a continuous phase, with the boundary between the phases called the "interface"<ref name=":2">{{Citation|last=Loi|first=Chia Chun|title=Protein-Stabilised Emulsions|date=2018|work=Reference Module in Food Science|publisher=Elsevier|doi=10.1016/b978-0-08-100596-5.22490-6|isbn=9780081005965|last2=Eyres|first2=Graham T.|last3=Birch|first3=E. John}}</ref>. Emulsions tend to have a cloudy appearance because the many [[phase boundary|phase interfaces]] [[scattering|scatter]] light as it passes through the emulsion. Emulsions appear [[white]] when all light is scattered equally. If the emulsion is dilute enough, higher-frequency (low-wavelength) light will be scattered more, and the emulsion will appear [[blue]]r&nbsp;– this is called the "[[Tyndall effect]]". {{Citation needed|date= February 2018}}If the emulsion is concentrated enough, the color will be distorted toward comparatively longer wavelengths, and will appear more [[yellow]]. This phenomenon is easily observable when comparing [[skimmed milk]], which contains little fat, to [[cream]], which contains a much higher concentration of milk fat. One example would be a mixture of water and oil.{{Citation needed|date= February 2018}} Two special classes of emulsions&nbsp;– [[microemulsion]]s and nanoemulsions, with droplet sizes below 100&nbsp;nm&nbsp;– appear translucent.<ref name="Mason">{{cite journal|vauthors=Mason TG, Wilking JN, Meleson K, Chang CB, Graves SM |title=Nanoemulsions: Formation, structure, and physical properties|journal=Journal of Physics: Condensed Matter|volume=18|issue=41|pages=R635–R666|doi=10.1088/0953-8984/18/41/R01|url=http://www.firp.ula.ve/archivos/pdf/06_JPCM_Mason.pdf|year=2006|bibcode=2006JPCM...18R.635M}}</ref> This property is due to the fact that light waves are scattered by the droplets only if their sizes exceed about one-quarter of the wavelength of the incident light. Since the [[visible spectrum]] of light is composed of wavelengths between 390 and 750 [[nanometer]]s (nm), if the droplet sizes in the emulsion are below about 100&nbsp;nm, the light can penetrate through the emulsion without being scattered.<ref>{{cite journal|vauthors=Leong TS, Wooster TJ, Kentish SE, Ashokkumar M |title=Minimising oil droplet size using ultrasonic emulsification|journal=Ultrasonics Sonochemistry|volume=16|issue=6|pages=721–7|pmid=19321375|year=2009|doi=10.1016/j.ultsonch.2009.02.008}}</ref> Due to their similarity in appearance, translucent nanoemulsions and [[microemulsions]] are frequently confused. Unlike translucent nanoemulsions, which require specialized equipment to be produced, microemulsions are spontaneously formed by “solubilizing” oil molecules with a mixture of [[surfactant]]s, co-surfactants, and co-[[solvent]]s.<ref name="Mason" /> The required surfactant concentration in a [[microemulsion]] is, however, several times higher than that in a translucent nanoemulsion, and significantly exceeds the concentration of the dispersed phase. Because of many undesirable side-effects caused by surfactants, their presence is disadvantageous or prohibitive in many applications. In addition, the stability of a microemulsion is often easily compromised by dilution, by heating, or by changing pH levels.{{Citation needed|date= February 2018}} Common emulsions are inherently unstable and, thus, do not tend to form spontaneously. Energy input&nbsp;– through shaking, stirring, [[Homogenization (chemistry)|homogenizing]], or exposure to power [[ultrasound]]<ref>{{cite journal| doi=10.1016/j.ifset.2007.07.005 | volume=9 | issue=2 | title=The use of ultrasonics for nanoemulsion preparation | year=2008 | journal=Innovative Food Science & Emerging Technologies | pages=170–175 | last1 = Kentish | first1 = S. | last2 = Wooster | first2 = T.J. | last3 = Ashokkumar | first3 = M. | last4 = Balachandran | first4 = S. | last5 = Mawson | first5 = R. | last6 = Simons | first6 = L.}}</ref>&nbsp;– is needed to form an emulsion. Over time, emulsions tend to revert to the stable state of the phases comprising the emulsion. An example of this is seen in the separation of the oil and vinegar components of [[vinaigrette (food)|vinaigrette]], an unstable emulsion that will quickly separate unless shaken almost continuously. There are important exceptions to this rule&nbsp;– [[microemulsions]] are [[thermodynamics|thermodynamically]] stable, while translucent nanoemulsions are [[Kinetics (physics)|kinetically]] stable.<ref name="Mason" /> Whether an emulsion of oil and water turns into a "water-in-oil" emulsion or an "oil-in-water" emulsion depends on the volume fraction of both phases and the type of emulsifier (surfactant) (see ''Emulsifier'', below) present.{{Citation needed|date= February 2018}} In general, the [[Bancroft rule]] applies. Emulsifiers and emulsifying particles tend to promote dispersion of the phase in which they do not dissolve very well. For example, proteins dissolve better in water than in oil, and so tend to form oil-in-water emulsions (that is, they promote the dispersion of oil droplets throughout a continuous phase of water).{{Citation needed|date= February 2018}} The geometric structure of an emulsion mixture of two lyophobic liquids with a large concentration of the secondary component is fractal: Emulsion particles unavoidably form dynamic inhomogeneous structures on small length scale. The geometry of these structures is fractal. The size of elementary irregularities is governed by a universal function which depends on the volume content of the components. The fractal dimension of these irregularities is 2.5.<ref>{{cite journal|author=Ozhovan M.I. |title=Dynamic uniform fractals in emulsions|journal= J. Exp. Theor. Phys.|volume= 77|issue=6|pages= 939–943 |year=1993|bibcode=1993JETP...77..939O|url=http://www.jetp.ac.ru/cgi-bin/dn/e_077_06_0939.pdf}}</ref> ===Instability=== Emulsion stability refers to the ability of an emulsion to resist change in its properties over time.<ref name=":0">{{cite book|author=McClements, David Julian |title=Food Emulsions: Principles, Practices, and Techniques, Second Edition|url=https://books.google.com/books?id=wTrzBPbf_WQC&pg=PA269|date=16 December 2004|publisher=[[Taylor & Francis]]|isbn=978-0-8493-2023-1|pages=269–}}</ref><ref>{{cite journal|doi=10.1016/S0268-005X(99)00027-2|title=Influence of copper on the stability of whey protein stabilized emulsions|journal=Food Hydrocolloids|volume=13|issue=5|pages=419|year=1999|last1=Silvestre|first1=M.P.C.|last2=Decker|first2=E.A.|last3=McClements|first3=D.J.}}</ref> There are four types of instability in emulsions: [[flocculation]], [[creaming (chemistry)|creaming]]/[[sedimentation]], [[Coalescence (physics)|coalescence]], and [[Ostwald ripening]]. Flocculation occurs when there is an attractive force between the droplets, so they form flocs, like bunches of grapes. Coalescence occurs when droplets bump into each other and combine to form a larger droplet, so the average droplet size increases over time. Emulsions can also undergo [[creaming (chemistry)|creaming]], where the droplets rise to the top of the emulsion under the influence of [[buoyancy]], or under the influence of the [[centripetal force]] induced when a [[centrifuge]] is used.<ref name=":0" /> Creaming is a common phenomenon in dairy and non-dairy beverages (i.e. milk, coffee milk, almond milk, soy milk) and usually does not change the droplet size.<ref name=":1">{{Cite journal|last=Loi|first=Chia Chun|last2=Eyres|first2=Graham T.|last3=Birch|first3=E. John|date=2019|title=Effect of mono- and diglycerides on physical properties and stability of a protein-stabilised oil-in-water emulsion|journal=Journal of Food Engineering|volume=240|pages=56–64|doi=10.1016/j.jfoodeng.2018.07.016|issn=0260-8774}}</ref> Sedimentation is the opposite phenomenon of creaming and normally observed in water-in-oil emulsions<ref name=":2" />. Sedimentation happens when the dispersed phase is denser than the continuous phase and the gravitational forces pull the denser globules towards the bottom of the emulsion. Similar to creaming, sedimentation follows Stoke’s law. An appropriate "surface active agent" (or "[[surfactant]]") can increase the kinetic stability of an emulsion so that the size of the droplets does not change significantly with time. The stability of an emulsion, like a [[Suspension_(chemistry)|suspension]], can be studied in terms of [[zeta potential]], which indicates the repulsion between droplets or particles. If the size and dispersion of droplets does not change over time, it is said to be stable.{{Citation needed|date= February 2018}} For example, oil-in-water emulsions containing [[Mono- and diglycerides of fatty acids|mono- and diglycerides]] and milk protein as [[surfactant]] showed that stable oil droplet size over 28 days storage at 25°C.<ref name=":1" /> ===Monitoring physical stability=== The stability of emulsions can be characterized using techniques such as light scattering, focused beam reflectance measurement, centrifugation, and rheology. Each method has advantages and disadvantages.{{Citation needed|date= February 2018}} ===Accelerating methods for shelf life prediction=== The kinetic process of destabilization can be rather long&nbsp;– up to several months, or even years for some products.{{Citation needed|date= February 2018}} Often the formulator must accelerate this process in order to test products in a reasonable time during product design. Thermal methods are the most commonly used – these consist of increasing the emulsion temperature to accelerate destabilization (if below critical temperatures for phase inversion or chemical degradation).{{Citation needed|date= February 2018}} Temperature affects not only the viscosity but also the inter-facial tension in the case of non-ionic surfactants or, on a broader scope, interactions of forces inside the system. Storing an emulsion at high temperatures enables the simulation of realistic conditions for a product (e.g., a tube of sunscreen emulsion in a car in the summer heat), but also to accelerate destabilization processes up to 200 times.{{Citation needed|date= February 2018}} Mechanical methods of acceleration, including vibration, centrifugation, and agitation, can also be used.{{Citation needed|date= February 2018}} These methods are almost always empirical, without a sound scientific basis.{{Citation needed|date= February 2018}} ==Emulsifiers== An '''emulsifier''' (also known as an "emulgent") is a substance that stabilizes an emulsion by increasing its [[chemical kinetics|kinetic stability]]. One class of emulsifiers is known as "surface active agents", or [[surfactant]]s. Emulsifiers are compounds that typically have a polar or hydrophilic (i.e. water-soluble) part and a non-polar (i.e. hydrophobic or lipophilic) part. Because of this, emulsifiers tend to have more or less solubility either in water or in oil.{{Citation needed|date= February 2018}} Emulsifiers that are more soluble in water (and conversely, less soluble in oil) will generally form oil-in-water emulsions, while emulsifiers that are more soluble in oil will form water-in-oil emulsions. <ref>Cassiday, L. (n.d.). Emulsions: Making oil and water mix. Retrieved from https://www.aocs.org/stay-informed/inform-magazine/featured-articles/emulsions-making-oil-and-water-mix-april-2014</ref> Examples of food emulsifiers are: * [[Egg yolk]]&nbsp;– in which the main emulsifying agent is [[lecithin]]. In fact, ''lecithos'' is the Greek word for egg yolk. * [[Mustard seed|Mustard]]&nbsp;– where a variety of chemicals in the [[mucilage]] surrounding the seed hull act as emulsifiers * [[Soy lecithin]] is another emulsifier and thickener * [[Pickering emulsion|Pickering stabilization]]&nbsp;– uses particles under certain circumstances * [[Sodium phosphates]] * [[Mono- and diglycerides of fatty acids|Mono- and diglycerides]] - a common emulsifier found in many food products (coffee creamers, ice-creams, spreads, breads, cakes) * [[Sodium stearoyl lactylate]] * [[DATEM]] (diacetyl tartaric acid esters of mono- and diglycerides)&nbsp;– an emulsifier used primarily in baking * Simple cellulose – a [[Pickering emulsion|particulate emulsifier]] derived from plant material using only water [[Detergent]]s are another class of surfactant, and will interact physically with both [[cooking oil|oil]] and [[water]], thus stabilizing the interface between the oil and water droplets in suspension. This principle is exploited in [[soap]], to remove [[yellow grease|grease]] for the purpose of [[cleaning agent|cleaning]]. Many different emulsifiers are used in [[pharmacy]] to prepare emulsions such as [[cream (pharmaceutical)|creams]] and [[lotion]]s. Common examples include [[emulsifying wax]], [[polysorbate 20]], and [[ceteareth|ceteareth 20]].<ref>{{cite web|url=http://www.teachsoap.com/emulsifywax.html|title=Using Emulsifying Wax|accessdate=2008-07-22|author=Anne-Marie Faiola|date=2008-05-21|website=TeachSoap.com|publisher=TeachSoap.com}}</ref> Sometimes the inner phase itself can act as an emulsifier, and the result is a nanoemulsion, where the inner state disperses into "[[nano-]]size" droplets within the outer phase. A well-known example of this phenomenon, the "[[ouzo effect]]", happens when water is poured into a strong alcoholic [[anise]]-based beverage, such as [[ouzo]], [[pastis]], [[absinthe]], [[Arak (distilled beverage)|arak]], or [[Rakı|raki]]. The anisolic compounds, which are soluble in [[ethanol]], then form nano-size droplets and emulsify within the water. The resulting color of the drink is opaque and milky white. ==Mechanisms of emulsification== A number of different chemical and physical processes and mechanisms can be involved in the process of emulsification:{{Citation needed|date= February 2018}} * Surface tension theory – according to this theory, emulsification takes place by reduction of interfacial tension between two phases * Repulsion theory – the emulsifying agent creates a film over one phase that forms globules, which repel each other. This repulsive force causes them to remain suspended in the dispersion medium * Viscosity modification – emulgents like [[Gum arabic|acacia]] and [[tragacanth]], which are hydrocolloids, as well as PEG (or [[polyethylene glycol]]), glycerine, and other polymers like CMC ([[carboxymethyl cellulose]]), all increase the viscosity of the medium, which helps create and maintain the suspension of globules of dispersed phase ==Uses== ===In food=== Oil-in-water emulsions are common in food products: * Crema (foam) in [[espresso]] – coffee oil in water (brewed coffee), unstable emulsion * [[Mayonnaise]] and [[Hollandaise sauce]]s – these are oil-in-water emulsions stabilized with egg yolk [[lecithin]], or with other types of food additives, such as [[sodium stearoyl lactylate]] * [[Homogenized milk]] – an emulsion of milk fat in water, with milk proteins as the emulsifier * [[Vinaigrette]] – an emulsion of vegetable oil in vinegar, if this is prepared using only oil and vinegar (i.e., without an emulsifier), an unstable emulsion results Water-in-oil emulsions are less common in food, but still exist: * [[Butter]] – an emulsion of water in butterfat * [[Margarine]] Other foods can be turned into products similar to emulsions, for example [[meat emulsion]] is a suspension of meat in liquid that is similar to true emulsions. ===Health care=== In [[pharmaceutics]], [[Hairstyling product|hairstyling]], [[personal hygiene]], and [[cosmetics]], emulsions are frequently used. These are usually oil and water emulsions but dispersed, and which is continuous depends in many cases on the [[pharmaceutical formulation]]. These emulsions may be called [[cream (pharmaceutical)|cream]]s, [[ointment]]s, [[liniment]]s (balms), [[paste (rheology)|paste]]s, [[Thin film|film]]s, or [[liquid]]s, depending mostly on their oil-to-water ratios, other additives, and their intended [[route of administration]].<ref name="Aulton">{{cite book|editor=Aulton, Michael E.|edition=3rd|title=Aulton's Pharmaceutics: The Design and Manufacture of Medicines|publisher=[[Churchill Livingstone]]|year=2007|isbn=978-0-443-10108-3|pages=92–97, 384, 390–405, 566–69, 573–74, 589–96, 609–10, 611}}</ref><ref name="Remington">{{Cite book|last1=Troy|first1=David A.|last2=Remington|first2=Joseph P.|last3=Beringer|first3=Paul|title=Remington: The Science and Practice of Pharmacy|edition=21st|year=2006|publisher=[[Lippincott Williams & Wilkins]]|location=Philadelphia|isbn=978-0-7817-4673-1|pages=325–336, 886–87}}</ref> The first 5 are [[topical]] [[dosage form]]s, and may be used on the surface of the [[human skin|skin]], [[transdermal]]ly, [[Eye drop|ophthalmically]], [[rectal]]ly, or [[vagina]]lly. A highly liquid emulsion may also be used [[oral administration|oral]]ly, or may be [[Injection (medicine)|injected]] in some cases.<ref name="Aulton"/> Microemulsions are used to deliver [[vaccine]]s and kill [[microbe]]s.<ref>{{cite web|url=http://www.nano.med.umich.edu/Platforms/Adjuvant-Vaccine-Development.html|title=Adjuvant Vaccine Development|accessdate=2008-07-23|deadurl=yes|archiveurl=https://web.archive.org/web/20080705134014/http://nano.med.umich.edu/Platforms/Adjuvant-Vaccine-Development.html|archivedate=2008-07-05|df=}}</ref> Typical emulsions used in these techniques are nanoemulsions of [[soybean oil]], with particles that are 400–600&nbsp;nm in diameter.<ref>{{cite web|url=http://www.eurekalert.org/pub_releases/2008-02/uomh-nvs022608.php|title=Nanoemulsion vaccines show increasing promise|accessdate=2008-07-22|website=Eurekalert! Public News List|publisher=University of Michigan Health System|date=2008-02-26}}</ref> The process is not chemical, as with other types of [[antimicrobial]] treatments, but mechanical. The smaller the droplet the greater the [[surface tension]] and thus the greater the force required to merge with other [[lipids]]. The oil is emulsified with detergents using a [[high-shear mixer]] to stabilize the emulsion so, when they encounter the lipids in the [[cell membrane]] or envelope of [[Cell envelope|bacteria]] or [[virus]]es, they force the lipids to merge with themselves. On a mass scale, in effect this disintegrates the membrane and kills the pathogen. The soybean oil emulsion does not harm normal human cells, or the cells of most other [[higher organisms]], with the exceptions of [[Spermatozoon|sperm cells]] and [[blood cells]], which are vulnerable to nanoemulsions due to the peculiarities of their membrane structures. For this reason, these nanoemulsions are not currently used [[intravenous]]ly (IV). The most effective application of this type of nanoemulsion is for the [[disinfection]] of surfaces. Some types of nanoemulsions have been shown to effectively destroy [[HIV-1]] and [[tuberculosis]] pathogens on non-[[porous]] surfaces. ===In firefighting=== Emulsifying agents are effective at extinguishing fires on small, thin-layer spills of flammable liquids ([[Fire classes|class B fire]]s). Such agents encapsulate the fuel in a fuel-water emulsion, thereby trapping the flammable vapors in the water phase. This emulsion is achieved by applying an [[Aqueous solution|aqueous]] surfactant solution to the fuel through a high-pressure nozzle. Emulsifiers are not effective at extinguishing large fires involving bulk/deep liquid fuels, because the amount of emulsifier agent needed for extinguishment is a function of the volume of the fuel, whereas other agents such as [[Fire-fighting foam|aqueous film-forming foam]] <!-- (AFFF) --> need cover only the surface of the fuel to achieve vapor mitigation.<ref>{{cite book|title=Principles of Fire Protection Chemistry and Physics |author=Friedman, Raymond |isbn= 978-0-87765-440-7|year=1998|publisher=[[Jones & Bartlett Learning]]}}</ref> ===Chemical synthesis=== {{main|Emulsion polymerization}} Emulsions are used to manufacture polymer dispersions – polymer production in an emulsion 'phase' has a number of process advantages, including prevention of coagulation of product. Products produced by such polymerisations may be used as the emulsions – products including primary components for glues and paints. Synthetic [[latex]]es (rubbers) are also produced by this process. ==See also== {{Div col|colwidth=18em}} * [[Emulsion dispersion]] * [[Emulsified fuel]] * [[Homogenizer]] * [[Liquid Whistle]] * [[Miniemulsion]] * [[Pickering emulsion]] * [[Rheology]] * [[Water-in-water emulsion]] * [[Latex]] {{div col end}} ==References== {{Reflist|30em}} ==Other sources== * {{cite book|author1=Philip Sherman|author2=[[British Society of Rheology]]|title=Rheology of emulsions: proceedings of a symposium held by the British Society of Rheology ... Harrogate, October 1962|url=https://books.google.com/books?id=UJ0FAQAAIAAJ|year=1963|publisher=Macmillan}} * ''Handbook of Nanostructured Materials and Nanotechnology; Nalwa, H.S., Ed.; Academic Press: New York, NY, USA, 2000; Volume 5, pp. 501–575'' {{Wiktionary}} {{Dosage forms|state=expanded}} {{Authority control}} [[Category:Colloidal chemistry]] [[Category:Chemical mixtures]] [[Category:Condensed matter physics]] [[Category:Soft matter]] [[Category:Drug delivery devices]] [[Category:Dosage forms]] [[Category:Colloids]]'