Surfactant
Overview
Surfactants are compounds that lower the surface tension
Surface tension
Surface tension is a property of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects to run on the water surface...

 of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agent
Foaming agent
A foaming agent is a surfactant, which when present in small amounts, facilitates the formation of a foam, or enhances its colloidal stability by inhibiting the coalescence of bubbles....

s, and dispersant
Dispersant
A dispersant or a dispersing agent or a plasticizer or a superplasticizer is either a non-surface active polymer or a surface-active substance added to a suspension, usually a colloid, to improve the separation of particles and to prevent settling or clumping...

s.

The term surfactant is a blend of surface active agents.

In Index Medicus
Index medicus
Index Medicus is a comprehensive index of medical scientific journal articles, published since 1879. It was initiated by John Shaw Billings, head of the Library of the Surgeon General's Office, United States Army...

 and the United States National Library of Medicine
United States National Library of Medicine
The United States National Library of Medicine , operated by the United States federal government, is the world's largest medical library. Located in Bethesda, Maryland, the NLM is a division of the National Institutes of Health...

, surfactant is reserved for the meaning pulmonary surfactant
Pulmonary surfactant
Pulmonary surfactant is a surface-active lipoprotein complex formed by type II alveolar cells. The proteins and lipids that surfactant comprises have both a hydrophilic region and a hydrophobic region...

.
Encyclopedia
Surfactants are compounds that lower the surface tension
Surface tension
Surface tension is a property of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects to run on the water surface...

 of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agent
Foaming agent
A foaming agent is a surfactant, which when present in small amounts, facilitates the formation of a foam, or enhances its colloidal stability by inhibiting the coalescence of bubbles....

s, and dispersant
Dispersant
A dispersant or a dispersing agent or a plasticizer or a superplasticizer is either a non-surface active polymer or a surface-active substance added to a suspension, usually a colloid, to improve the separation of particles and to prevent settling or clumping...

s.

Etymology

The term surfactant is a blend of surface active agents.

In Index Medicus
Index medicus
Index Medicus is a comprehensive index of medical scientific journal articles, published since 1879. It was initiated by John Shaw Billings, head of the Library of the Surgeon General's Office, United States Army...

 and the United States National Library of Medicine
United States National Library of Medicine
The United States National Library of Medicine , operated by the United States federal government, is the world's largest medical library. Located in Bethesda, Maryland, the NLM is a division of the National Institutes of Health...

, surfactant is reserved for the meaning pulmonary surfactant
Pulmonary surfactant
Pulmonary surfactant is a surface-active lipoprotein complex formed by type II alveolar cells. The proteins and lipids that surfactant comprises have both a hydrophilic region and a hydrophobic region...

. For the more general meaning, surface active agent is the heading.

Definition

Surfactants are usually organic compound
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

s that are amphiphilic, meaning they contain both hydrophobic groups (their tails) and hydrophilic groups (their heads). Therefore, a surfactant molecule contains both a water insoluble (or oil soluble) component and a water soluble component. Surfactant molecules will diffuse in water and adsorb
Adsorption
Adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...

 at interfaces between air and water or at the interface between oil and water, in the case where water is mixed with oil. The insoluble hydrophobic group may extend out of the bulk water phase, into the air or into the oil phase, while the water soluble head group remains in the water phase. This alignment of surfactant molecules at the surface modifies the surface properties of water at the water/air or water/oil interface.

Structure of surfactant phases in water

In the bulk aqueous phase, surfactants form aggregates, such as micelles, where the hydrophobic tails form the core of the aggregate and the hydrophilic heads are in contact with the surrounding liquid. Other types of aggregates such as spherical or cylindrical micelles or bilayers can be formed. The shape of the aggregates depends on the chemical structure of the surfactants, depending on the balance of the sizes of the hydrophobic tail and hydrophilic tail. This is known as the HLB, Hydrophilic-lipophilic balance.

Adsorbed layers of surfactants at equilibrium

Surfactants reduce the surface tension
Surface tension
Surface tension is a property of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects to run on the water surface...

 of water by adsorbing
Adsorption
Adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...

 at the liquid-gas interface. The decrease of the surface tension depends on the number of adsorbed molecules per unit area, called the surface excess. The relation that links the surface tension and the surface excess is known as the Gibbs isotherm
Gibbs isotherm
The Gibbs adsorption isotherm for multicomponent systems is an equation used to relate the changes in concentration of a component in contact with a surface with changes in the surface tension...

.

Dynamics of surfactants at interfaces

The dynamics of adsorption of surfactants is of great importance for practical applications such as foaming, emulsifying or coating processes, where bubbles or drops are rapidly generated and need to be stabilized. The dynamics of adsorption depends on the diffusion coefficient of the surfactants. Indeed, as the interface is created, the adsorption is limited by the diffusion of the surfactants to the interface. In some cases, there exists a barrier of energy for the adsorption or the desorption of the surfactants, then the adsorption dynamics is known as 'kinetically-limited'. Such energy barrier can be due to steric or electrostatic repulsions.
The surface rheology
Surface rheology
Surface rheology is a description of the rheological properties of a free surface. When perfectly pure, the interface between fluids usually displays only surface tension...

 of surfactant layers, including the elasticity and viscosity of the surfactant layers plays a very important role in foam or emulsion stability and rheology
Rheology
Rheology is the study of the flow of matter, primarily in the liquid state, but also as 'soft solids' or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an applied force....

.

Characterization of interfaces and surfactant layers

Interfacial and surface tension can be characterized by classical methods such as the
-pendant or spinning drop method
Dynamic surface tensions, i.e surface tension as a function of time, can be obtained by the Maximum Bubble Pressure apparatus

The structure of surfactant layers can be studied by ellipsometry
Ellipsometry
Ellipsometry is an optical technique for the investigation of the dielectric properties of thin films....

 or X-Ray reflectivity.

Surface rheology
Surface rheology
Surface rheology is a description of the rheological properties of a free surface. When perfectly pure, the interface between fluids usually displays only surface tension...

 can be characterized by the oscillating drop method or shear surface rheometers such as double-cone, double-ring or magnetic rod shear surface rheometer.

Applications

Surfactants play an important role as cleaning, wetting
Wetting
Wetting is the ability of a liquid to maintain contact with a solid surface, resulting from intermolecular interactions when the two are brought together. The degree of wetting is determined by a force balance between adhesive and cohesive forces.Wetting is important in the bonding or adherence of...

, dispersing
Dispersant
A dispersant or a dispersing agent or a plasticizer or a superplasticizer is either a non-surface active polymer or a surface-active substance added to a suspension, usually a colloid, to improve the separation of particles and to prevent settling or clumping...

, emulsifying, foaming
Foaming agent
A foaming agent is a surfactant, which when present in small amounts, facilitates the formation of a foam, or enhances its colloidal stability by inhibiting the coalescence of bubbles....

 and anti-foaming
Defoamer
A defoamer or an anti-foaming agent is a chemical additive that reduces and hinders the formation of foam in industrial process liquids. The terms anti-foam agent and defoamer are often used interchangeably....

 agents in many practical applications and products, including:
  • Detergent
    Detergent
    A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap but are less affected by hard water...

    s
  • Fabric softener
    Fabric softener
    Fabric softener is used to prevent static cling and make fabric softer. It is available as a liquid, crystals and dryer sheets.- Varieties :...

    s
  • Emulsion
    Emulsion
    An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...

    s
  • Paint
    Paint
    Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...

    s
  • Adhesive
    Adhesive
    An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials...

    s
  • Ink
    Ink
    Ink is a liquid or paste that contains pigments and/or dyes and is used to color a surface to produce an image, text, or design. Ink is used for drawing and/or writing with a pen, brush, or quill...

    s
  • Anti-fog
    Anti-fog
    Anti-fog agents, also known as anti-fogging agents and treatments, are chemicals which prevent the condensation of water in the form of small droplets on a surface which resemble fog...

    s
  • Ski wax
    Ski wax
    Ski wax is a material applied to the bottom of skis or snowboards to improve the ski's performance on snow. It can also be applied to other devices that slide over snow and ice such as toboggans.- Types of ski wax :...

    es, snowboard wax
  • Deinking
    Deinking
    Deinking is the industrial process of removing printing ink from paperfibers of recycled paper to make deinked pulp.The key in the deinking process is the ability to detach ink from the fibers. This is achieved by a combination of mechanical action and chemical means. In Europe the most common...

     of recycled papers, in flotation, washing and enzymatic processes
  • Laxative
    Laxative
    Laxatives are foods, compounds, or drugs taken to induce bowel movements or to loosen the stool, most often taken to treat constipation. Certain stimulant, lubricant, and saline laxatives are used to evacuate the colon for rectal and/or bowel examinations, and may be supplemented by enemas under...

    s
  • Agrochemical formulations
    • Herbicide
      Herbicide
      Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...

      s (some)
    • Insecticide
      Insecticide
      An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...

      s
  • Quantum dot
    Quantum dot
    A quantum dot is a portion of matter whose excitons are confined in all three spatial dimensions. Consequently, such materials have electronic properties intermediate between those of bulk semiconductors and those of discrete molecules. They were discovered at the beginning of the 1980s by Alexei...

     coatings
  • Biocide
    Biocide
    A biocide is a chemical substance or microorganism which can deter, render harmless, or exert a controlling effect on any harmful organism by chemical or biological means. Biocides are commonly used in medicine, agriculture, forestry, and industry...

    s (sanitizers)
  • Cosmetics
    Cosmetics
    Cosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...

    :
    • Shampoo
      Shampoo
      Shampoo is a hair care product used for the removal of oils, dirt, skin particles, dandruff, environmental pollutants and other contaminant particles that gradually build up in hair...

      s
    • Hair conditioner
      Hair conditioner
      Hair conditioner is a hair care product that alters the texture and appearance of hair.-History:For centuries, natural oils have been used to condition human hair. These natural products are still used today, including essential oils such as tea tree oil and carrier oils such as jojoba oil...

      s (after shampoo)
    • Toothpaste
      Toothpaste
      Toothpaste is a paste or gel dentifrice used with a toothbrush as an accessory to clean and maintain the aesthetics and health of teeth. Toothpaste is used to promote oral hygiene: it serves as an abrasive that aids in removing the dental plaque and food from the teeth, assists in suppressing...

      s
  • Spermicide
    Spermicide
    Spermicide is a contraceptive substance that eradicates sperm, inserted vaginally prior to intercourse to prevent pregnancy. As a contraceptive, spermicide may be used alone. However, the pregnancy rate experienced by couples using only spermicide is higher than that of couples using other methods...

    s (nonoxynol-9
    Nonoxynol-9
    Nonoxynol-9, sometimes abbreviated as N-9, is an organic compound that is used as a surfactant. It is a member of the nonoxynol family of nonionic surfactants. N-9 and related compounds are ingredients in various cleaning and cosmetic products. It is widely used in contraceptives for its...

    )
  • Firefighting
  • Pipelines, liquid drag reducing agent
  • Alkali Surfactant Polymers (used to mobilize oil in oil well
    Oil well
    An oil well is a general term for any boring through the earth's surface that is designed to find and acquire petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A well that is designed to produce mainly or only gas may be termed a gas well.-History:The earliest...

    s)
  • Ferrofluid
    Ferrofluid
    A ferrofluid is a liquid which becomes strongly magnetized in the presence of a magnetic field.Ferrofluids are colloidal liquids made of nanoscale ferromagnetic, or ferrimagnetic, particles suspended in a carrier fluid . Each tiny particle is thoroughly coated with a surfactant to inhibit clumping...

    s
  • Leak Detectors

Detergents in biochemistry and biotechnology

In solution, detergents help solubilize molecules by dissociating aggregates and unfolding proteins, including SDS, CTAB. Detergents are key reagents to extract
Liquid-liquid extraction
Liquid–liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their relative solubilities in two different immiscible liquids, usually water and an organic solvent. It is an extraction of a substance from one liquid phase into another liquid...

 protein by lysis of the cells and tissues: They disorganize the membrane's lipidic bilayer (SDS, Triton X-100, X-114, CHAPS
CHAPS detergent
CHAPS is a zwitterionic detergent used in the laboratory to solubilize biological macromolecules such as proteins. It is used as a non-denaturing solvent in the process of protein purification and is especially useful in purifying membrane proteins, which are often sparingly soluble or insoluble in...

, DOC, and NP-40
NP-40
NP-40 is a commercially available detergent. The full name of NP-40 is Tergitol-type NP-40, which is nonyl phenoxypolyethoxylethanol.Care should be taken to avoid confusing NP-40 with Nonidet P-40 ....

), and solubilize proteins. Milder detergents such as (OctylThioGlucosides) are used to solubilize sensible proteins (enzymes, receptors
Receptor (biochemistry)
In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

). Non-solubilized material is harvested by centrifugation or other means. For electrophoresis
Electrophoresis
Electrophoresis, also called cataphoresis, is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. This electrokinetic phenomenon was observed for the first time in 1807 by Reuss , who noticed that the application of a constant electric...

, for example, proteins are classically treated with SDS to denature the native tertiary and quaternary structures
Protein structure
Proteins are an important class of biological macromolecules present in all organisms. Proteins are polymers of amino acids. Classified by their physical size, proteins are nanoparticles . Each protein polymer – also known as a polypeptide – consists of a sequence formed from 20 possible L-α-amino...

, allowing the separation of proteins according to their molecular weight.

Detergents have also been used to decellularise organs. This process maintains a matrix of proteins that preserves the structure of the organ and often the microvascular network. The process has been successfully used to prepare organs such as the liver and heart for transplant in rats. Pulmonary surfactant
Pulmonary surfactant
Pulmonary surfactant is a surface-active lipoprotein complex formed by type II alveolar cells. The proteins and lipids that surfactant comprises have both a hydrophilic region and a hydrophobic region...

s are also naturally secreted by type II cells of the lung alveoli in mammals.

Classification of surfactants

Surfactants can have a cationic, anionic or neutral head.
There exists several types of hydrophobic tails.

see classification of surfactants
Classification of surfactants
Surfactants are classified according to their chemical structure and their counter ion.-According to the composition of their tail:The tail of surfactants can be:...


Current market

The annual global production of surfactants was 13 million metric tons in 2008,, and the annual turnover reached US$24.33 billion in 2009, nearly 2% up from the previous year. The market is expected to experience quite healthy growth by 2.8% annually to 2012 and by 3.5 - 4% thereafter.

Health and environmental controversy

Some surfactants are known to be toxic to animals, ecosystems, and humans, and can increase the diffusion of other environmental contaminants. Despite this, they are routinely deposited in numerous ways on land and into water systems, whether as part of an intended process or as industrial and household waste. Some surfactants have proposed or voluntary restrictions on their use. For example, PFOS is a persistent organic pollutant
Persistent organic pollutant
thumb|right|275px|State parties to the Stockholm Convention on Persistent Organic PollutantsPersistent organic pollutants are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes...

 as judged by the Stockholm Convention
Stockholm Convention
Stockholm Convention on Persistent Organic Pollutants is an international environmental treaty, signed in 2001 and effective from May 2004, that aims to eliminate or restrict the production and use of persistent organic pollutants .- History :...

. Additionally, PFOA has been subject to a voluntary agreement by the U.S. Environmental Protection Agency‎ and eight chemical companies to reduce and eliminate emissions of the chemical and its precursors.

The two major surfactants used in the year 2000 were linear alkylbenzene sulphonates (LAS) and the alkyl phenol ethoxylates (APE). They break down in the aerobic conditions found in sewage treatment
Sewage treatment
Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants...

 plants and in soil.

Ordinary dishwashing detergent
Detergent
A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap but are less affected by hard water...

, for example, will promote water penetration in soil, but the effect would last only a few days (many standard laundry detergent powders contain levels of chemicals such as alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...

 and chelating agents
Chelation
Chelation is the formation or presence of two or more separate coordinate bonds between apolydentate ligand and a single central atom....

 that can be damaging to plants and should not be applied to soils). Commercial soil wetting agents will continue to work for a considerable period, but they will eventually be degraded by soil micro-organisms. Some can, however, interfere with the life-cycles of some aquatic organisms, so care should be taken to prevent run-off of these products into streams, and excess product should not be washed down.

Anionic surfactants can be found in soils as the result of sludge application, wastewater irrigation, and remediation processes. Relatively high concentrations of surfactants together with multimetals can represent an environmental risk. At low concentrations, surfactant application is unlikely to have a significant effect on trace metal mobility.

Biosurfactants

Biosurfactants are surface-active substances synthesised by living cells; they are generally non-toxic and biodegradable. Interest in microbial surfactants has been steadily increasing in recent years due to their diversity, environmentally friendly nature, possibility
of large-scale production, selectivity, performance under extreme conditions, and potential applications in environmental protection.

Biosurfactants enhance the emulsification of hydrocarbons, have the potential to solubilise hydrocarbon contaminants and increase their availability for microbial degradation. The use of chemicals for the treatment of a hydrocarbon polluted site may contaminate the environment with their by-products, whereas biological treatment may efficiently destroy pollutants, while being biodegradable themselves. Hence, biosurfactant-producing microorganisms may play an important role in the accelerated bioremediation of hydrocarbon-contaminated sites. These compounds can also be used in enhanced oil recovery
Enhanced oil recovery
Enhanced Oil Recovery is a generic term for techniques for increasing the amount of crude oil that can be extracted from an oil field...

 and may be considered for other potential applications in environmental protection. Other applications include herbicides and
pesticides formulations, detergents, healthcare and cosmetics, pulp and paper, coal, textiles, ceramic processing and food industries, uranium ore-processing, and mechanical dewatering of peat.

Several microorganisms are known to synthesise surface-active agents; most of them are bacteria and yeasts. When grown on hydrocarbon substrate as the carbon source, these microorganisms synthesise a wide range of chemicals with surface activity, such as glycolipid, phospholipid, and others. These chemicals are synthesised to emulsify the hydrocarbon substrate and facilitate its transport into the cells. In some bacterial species such as Pseudomonas aeruginosa
Pseudomonas aeruginosa
Pseudomonas aeruginosa is a common bacterium that can cause disease in animals, including humans. It is found in soil, water, skin flora, and most man-made environments throughout the world. It thrives not only in normal atmospheres, but also in hypoxic atmospheres, and has, thus, colonized many...

, biosurfactants are also involved in a group motility behavior called swarming motility
Swarming motility
Swarming motility is a rapid and coordinated translocation of a bacterial population across solid or semi-solid surfaces. This type of motility is an example of an emerging concept in microbiology : bacterial multicellularity...

.

Biosurfactants and Deepwater Horizon

The use of biosurfactants as a way to remove petroleum
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

 from contaminated sites has been questioned, and criticized as irresponsible and environmentally unsafe. Biosurfactants were not used by BP
BP
BP p.l.c. is a global oil and gas company headquartered in London, United Kingdom. It is the third-largest energy company and fourth-largest company in the world measured by revenues and one of the six oil and gas "supermajors"...

 after the Deepwater Horizon
Deepwater Horizon
Deepwater Horizon was an ultra-deepwater, dynamically positioned, semi-submersible offshore oil drilling rig owned by Transocean. Built in 2001 in South Korea by Hyundai Heavy Industries, the rig was commissioned by R&B Falcon, which later became part of Transocean, registered in Majuro, Marshall...

 offshore drilling rig went down on April 20, 2010, on the resulting Deepwater Horizon oil spill
Deepwater Horizon oil spill
The Deepwater Horizon oil spill is an oil spill in the Gulf of Mexico which flowed unabated for three months in 2010, and continues to leak fresh oil. It is the largest accidental marine oil spill in the history of the petroleum industry...

. However, unprecedented amounts of Corexit
Corexit
Corexit is a product line of solvents primarily used as a dispersant for breaking up oil slicks. It is produced by Nalco Holding Company which is associated with BP and Exxon. Corexit was the most-used dispersant in the Deepwater Horizon oil spill in the Gulf of Mexico, with COREXIT 9527 having...

, a surfactant solution produced by Nalco Holding Company
Nalco Holding Company
Nalco Holding Company supplies water treatment and process improvement services, chemicals and equipment programs for industrial and institutional markets. These products and services are marketed in some cases to prevent corrosion, contamination and the buildup of harmful deposits...

 (whose active ingredient is Tween-80), were sprayed directly into the ocean at the leak and on the sea-water's surface, the theory being that the surfactants would isolate individual molecules of oil, making it easier for petroleum-consuming microbes to digest the oil. However, some scientists say that, rather than helping the situation, the surfactants have managed only to disperse and sink the oil below the surface and out of sight . Naturally occurring petroleum-consuming microbes have evolved on the bottom of the ocean, where they have adapted to live in areas where oil seeps naturally from the ocean floor.

See also

  • Anti-fog
    Anti-fog
    Anti-fog agents, also known as anti-fogging agents and treatments, are chemicals which prevent the condensation of water in the form of small droplets on a surface which resemble fog...

  • Cleavable detergent
    Cleavable detergent
    Cleavable detergents, also known as cleavable surfactants, are special surfactants that are used in biochemistry and especially in proteomics to enhance protein denaturation and solubility...

  • MBAS assay
    MBAS assay
    A methylene blue active substances assay, or MBAS assay, is a colorimetric analysis test method that uses methylene blue to detect the presence of anionic surfactants in a sample of water...

    , an assay
    Assay
    An assay is a procedure in molecular biology for testing or measuring the activity of a drug or biochemical in an organism or organic sample. A quantitative assay may also measure the amount of a substance in a sample. Bioassays and immunoassays are among the many varieties of specialized...

     that indicates anionic surfactant
    Surfactant
    Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...

    s in water with a bluing reaction.
  • Niosome
  • Emulsion
    Emulsion
    An emulsion is a mixture of two or more liquids that are normally immiscible . Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion is used when both the dispersed and the...

  • Pulmonary surfactant
    Pulmonary surfactant
    Pulmonary surfactant is a surface-active lipoprotein complex formed by type II alveolar cells. The proteins and lipids that surfactant comprises have both a hydrophilic region and a hydrophobic region...

  • Surfactants in paint
    Surfactants in paint
    Paint has four major components: pigments, binders, solvents, and other additives. Pigments serve to give paint its color, texture, toughness, as well as determining if a paint is opaque or not. Common white pigments include titanium dioxide TiO2 and zinc oxide ZnO. Binders are the film that forms...


External links

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