Classification of surfactants
Encyclopedia
Surfactants are classified according to their chemical structure (head and tail) and their counter ion.
A surfactant can have one or two tails, these are called double-chained.
Some commonly encountered surfactants of each type include:
According to the composition of their tail
The tail of surfactants can be:- A hydrocarbonHydrocarbonIn organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
chain: aromatic hydrocarbonAromatic hydrocarbonAn aromatic hydrocarbon or arene is a hydrocarbon with alternating double and single bonds between carbon atoms. The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered, and was derived from the fact that many of the compounds have a sweet scent...
s (arenes), alkaneAlkaneAlkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...
s (alkyl), alkeneAlkeneIn organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...
s, cycloalkanes, alkyneAlkyneAlkynes are hydrocarbons that have a triple bond between two carbon atoms, with the formula CnH2n-2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature...
-based - An alkyl etherEtherEthers are a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R'. A typical example is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether"...
chain:- Ethoxylated surfactants: polyethylene oxides are inserted to increase the hydrophilic character of a surfactant
- Propoxylated surfactants: polypropylene oxides are inserted to increase the lipophilic character of a surfactant
- A fluorocarbonFluorocarbonFluorocarbons, sometimes referred to as perfluorocarbons or PFCs, are organofluorine compounds that contain only carbon and fluorine bonded together in strong carbon–fluorine bonds. Fluoroalkanes that contain only single bonds are more chemically and thermally stable than alkanes...
chain: fluorosurfactantFluorosurfactantFluorosurfactants, or fluorinated surfactants, are synthetic organofluorine chemical compounds that have multiple fluorine atoms. They can be polyfluorinated or fluorocarbon-based . As surfactants, they are more effective at lowering the surface tension of water than comparable hydrocarbon...
s - A siloxaneSiloxaneA siloxane is any chemical compound composed of units of the form R2SiO, where R is a hydrogen atom or a hydrocarbon group. They belong to the wider class of organosilicon compounds....
chain: siloxane surfactants.
A surfactant can have one or two tails, these are called double-chained.
According to the composition of their head
A surfactant can be classified by the presence of formally charged groups in its head. A non-ionic surfactant has no charge groups in its head. The head of an ionic surfactant carries a net charge. If the charge is negative, the surfactant is more specifically called anionic; if the charge is positive, it is called cationic. If a surfactant contains a head with two oppositely charged groups, it is termed zwitterionic.Some commonly encountered surfactants of each type include:
- Ionic
- Anionic: based on permanent anions (sulfateSulfuric acidSulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
, sulfonateSulfonateA sulfonate is a salt or ester of a sulfonic acid. It contains the functional group R-SO2O-.- Sulfonate salts:Anions with the general formula RSO2O− are called sulfonates. They are the conjugate bases of sulfonic acids with formula RSO2OH. As sulfonic acids tend to be strong acids, the...
, phosphatePhosphateA phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
) or pH-dependent anions (carboxylateCarboxylic acidCarboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...
):- Sulfates
- Alkyl sulfates: ammonium lauryl sulfateAmmonium lauryl sulfateAmmonium lauryl sulfate is the common name for ammonium dodecyl sulfate . The dodecyl signifies the presence of a 12-member carbon chain in the molecular backbone which allows the molecule to bond with non-polar portions of molecules while the highly polar sulfate head allows the molecule to bond...
, sodium lauryl sulfate (SDS, sodium dodecyl sulfate, another name for the compound) - Alkyl ether sulfates: sodium laureth sulfateSodium laureth sulfateSodium laureth sulfate, or sodium lauryl ether sulfate , is a detergent and surfactant found in many personal care products . SLES is an inexpensive and very effective foaming agent. SLES, SLS and ALS are surfactants that are used in many cosmetic products for their cleansing and emulsifying...
, also known as sodium lauryl ether sulfate (SLES), sodium myreth sulfateSodium myreth sulfateSodium myreth sulfate is a mixture of organic compounds with both detergent and surfactant properties. It is found in many personal care products such as soaps, shampoos, and toothpaste. It is an inexpensive and effective foaming agent. Typical of many detergents, sodium myreth sulfate consists of...
- Alkyl sulfates: ammonium lauryl sulfate
- Sulfonates:
- Docusates: dioctyl sodium sulfosuccinateDioctyl sodium sulfosuccinateDioctyl sodium sulfosuccinate or docusate sodium – often referred to as DSS, Aerosol OT or AOT – is a common ingredient in consumer products, especially laxatives of the stool softener type...
- Sulfonate fluorosurfactants: perfluorooctanesulfonate (PFOS), perfluorobutanesulfonatePerfluorobutanesulfonic acidPerfluorobutanesulfonic acid is a chemical compound with a four carbon fluorocarbon chain and a sulfonic acid functional group. As an anion it functions as a stable fluorosurfactant because of the strength of carbon–fluorine bonds....
- Alkyl benzene sulfonates
- Docusates: dioctyl sodium sulfosuccinate
- Phosphates:
- Alkyl aryl ether phosphate
- Alkyl ether phosphate
- Carboxylates:
- Alkyl carboxylates: Fatty acidFatty acidIn chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
saltSaltIn chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
s (soapSoapIn chemistry, soap is a salt of a fatty acid.IUPAC. "" Compendium of Chemical Terminology, 2nd ed. . Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford . XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN...
s): sodium stearateSodium stearateSodium stearate, or sodium octadecanoate, is the sodium salt of stearic acid. It is the major component of some types of soap, especially those made from animal fat. It is found in many types of solid deodorants, rubbers, latex paints, and inks. It is also a component of some food additives and...
; - Sodium lauroyl sarcosinateSodium lauroyl sarcosinateSodium lauroyl sarcosinate , also known as sarkosyl, is an ionic surfactant derived from sarcosine, used as a foaming and cleansing agent in shampoo, shaving foam and foam wash products....
- Carboxylate fluorosurfactants: perfluorononanoatePerfluorononanoic acidPerfluorononanoic acid, or PFNA, is a synthetic perfluorinated carboxylic acid and fluorosurfactant that is also an environmental contaminant found in people and wildlife along with PFOS and PFOA.-Chemistry and properties:...
, perfluorooctanoatePerfluorooctanoic acidPerfluorooctanoic acid , also known as C8 and perfluorooctanoate, is a synthetic, stable perfluorinated carboxylic acid and fluorosurfactant. One industrial application is as a surfactant in the emulsion polymerization of fluoropolymers. It has been used in the manufacture of such prominent...
(PFOA or PFO)
- Alkyl carboxylates: Fatty acid
- Sulfates
- Anionic: based on permanent anions (sulfate
-
- Cationic: based on:
- pH-dependent primary, secondary, or tertiary amineAmineAmines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...
s: Primary amines become positively charged at pH < 10, secondary amines become charged at pH < 4:- Octenidine dihydrochlorideOctenidine dihydrochlorideOctenidine dihydrochloride is a cationic surfactant and bis--decane derivative, used in concentrations of 0.1–2.0%. It is similar in its action to the quaternary ammonium compounds , but is of somewhat broader spectrum of activity...
;
- Octenidine dihydrochloride
- Permanently charged quaternary ammonium cationQuaternary ammonium cationQuaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure NR4+, R being an alkyl group or an aryl group. Unlike the ammonium ion and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged,...
:- Alkyltrimethylammonium salts: cetyl trimethylammonium bromide (CTAB) a.k.a. hexadecyl trimethyl ammonium bromide, cetyl trimethylammonium chlorideCetrimonium chlorideCetrimonium chloride is a topical antiseptic. It is also commonly used in hair conditioners and shampoos, as a conditioning agent.- References:...
(CTAC - Cetylpyridinium chlorideCetylpyridinium chlorideCetylpyridinium chloride is a cationic quaternary ammonium compound in some types of mouthwashes, toothpastes, lozenges, throat sprays, breath sprays, and nasal sprays. It is an antiseptic that kills bacteria and other microorganisms. It has been shown to be effective in preventing dental plaque...
(CPC) - Benzalkonium chlorideBenzalkonium chlorideBenzalkonium chloride, also known as alkyldimethylbenzylammonium chloride and ADBAC, is a mixture of alkylbenzyldimethylammonium chlorides of various even-numbered alkyl chain lengths. This product is a nitrogenous cationic surface-acting agent belonging to the quaternary ammonium group...
(BAC) - Benzethonium chlorideBenzethonium chlorideBenzethonium chloride is a synthetic quaternary ammonium salt. This compound is an odorless white solid; soluble in water. It has surfactant, antiseptic, and anti-infective properties, and it is used as a topical antimicrobial agent in first aid antiseptics. It is also found in cosmetics and...
(BZT) - 5-Bromo-5-nitro-1,3-dioxaneBronidoxBronidox, or 5-bromo-5-nitro-1,3-dioxane, is an antimicrobial chemical compound.Bronidox causes inhibition of enzyme activity in bacteria.Bronidox is corrosive to metals.- Uses :* Stabilizer* Surfactant...
- Dimethyldioctadecylammonium chloride
- Dioctadecyldimethylammonium bromide (DODABDODABDioctadecyldimethylammonium bromide is a doublechained quaternary ammonium surfactant that forms unilamellar vesicles in water. Among various preparation methods, the ‘‘hot-water” method offers a simple procedure to prepare DODAB cationic vesicles by simply dissolving the DODAB in hot water...
)
- Alkyltrimethylammonium salts: cetyl trimethylammonium bromide (CTAB) a.k.a. hexadecyl trimethyl ammonium bromide, cetyl trimethylammonium chloride
- pH-dependent primary, secondary, or tertiary amine
- Cationic: based on:
-
- ZwitterionZwitterionIn chemistry, a zwitterion is a neutral molecule with a positive and a negative electrical charge at different locations within that molecule. Zwitterions are sometimes also called inner salts.-Examples:...
ic (amphoteric): based on primary, secondary, or tertiary amineAmineAmines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...
s or quaternary ammonium cation with:- Sulfonates:
- CHAPSCHAPS detergentCHAPS 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...
(3-[(3-Cholamidopropyl)dimethylammonio]-1-propanesulfonate); - SultainesHydroxysultaineHydroxysultaines find their main use in high-foaming shampoos, bath products and shower gels especially in conjunction with ether sulfates and alkyl sulfates. They are also used in industrial applications where high, stable foam is required. Hydroxysultaines are also compatible with cationic...
: cocamidopropyl hydroxysultaineCocamidopropyl hydroxysultaineCocamidopropyl hydroxysultaine is a synthetic amphoteric surfactant from the hydroxysultaine group. It is found in many personal care products . It has uses as a foam booster, viscosity builder, and an antistatic agent...
;
- CHAPS
- Carboxylates:
- Amino acidAmino acidAmino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
s - Imino acidImino acidIn chemistry, an imino acid is any molecule that contains both imino and carboxyl functional groups.Imino acids are related to amino acids, which contain both amino and carboxyl functional groups...
s - Betaines: cocamidopropyl betaineCocamidopropyl betaineCocamidopropyl betaine is a synthetic surfactant derived from coconut oil and dimethylaminopropylamine. It is a zwitterionic chemical compound with a quaternary ammonium cation...
;
- Amino acid
- Phosphates: lecithinLecithinLecithin is a generic term to designate any group of yellow-brownish fatty substances occurring in animal and plant tissues, and in egg yolk, composed of phosphoric acid, choline, fatty acids, glycerol, glycolipids, triglycerides, and phospholipids .The word lecithin was originally coined in 1847 by...
- Sulfonates:
- Zwitterion
- Nonionic
- Fatty alcoholFatty alcoholFatty alcohols are aliphatic alcohols consisting of a chain of 8 to 22 carbon atoms. Fatty alcohols usually have even number of carbon atoms and a single alcohol group attached to the terminal carbon. Some are unsaturated and some are branched...
s:- Cetyl alcoholCetyl alcoholCetyl alcohol, also known as 1-hexadecanol and palmityl alcohol, is a fatty alcohol with the chemical formula CH315OH. At room temperature, cetyl alcohol takes the form of a waxy white solid or flakes....
- Stearyl alcoholStearyl alcoholStearyl alcohol is a substance prepared from stearic acid by the process of catalytic hydrogenation. It is a fatty alcohol. It takes the form of white solid granules or flakes which are insoluble in water, with a melting point of 60 °C and boiling point of 210 °C...
- Cetostearyl alcohol (consisting predominantly of cetyl and stearyl alcohols)
- Oleyl alcoholOleyl alcoholOleyl alcohol, octadecenol, or cis-9-octadecen-1-ol, is a fatty alcohol coming from inedible beef fat. It is also found in fish oil.Its chemical formula is 1836 or CH37-CH=CH-8OH.It is a non-ionic, unsaturated fatty alcohol....
- Cetyl alcohol
- Polyoxyethylene glycolPolyethylene glycolPolyethylene glycol is a polyether compound with many applications from industrial manufacturing to medicine. It has also been known as polyethylene oxide or polyoxyethylene , depending on its molecular weight, and under the tradename Carbowax.-Available forms:PEG, PEO, or POE refers to an...
alkyl ethers (Brij): CH3–(CH2)10–16–(O-C2H4)1–25–OH:- Octaethylene glycol monododecyl etherOctaethylene glycol monododecyl etherOctaethylene glycol monododecyl ether is a nonionic surfactant. Its critical micelle concentration is 8×10-5 M at 25 °C....
- Pentaethylene glycol monododecyl etherPentaethylene glycol monododecyl etherPentaethylene glycol monododecyl ether is a nonionic surfactant. Its critical micelle concentration is 7×10-5 M at 25 °C.-MLV Formation:...
- Octaethylene glycol monododecyl ether
- Polyoxypropylene glycolPolypropylene glycolPolypropylene glycol or polypropylene oxide is the polymer of propylene glycol. Chemically it is a polyether. The term polypropylene glycol or PPG is reserved for low to medium range molar mass polymer when the nature of the end-group, which is usually a hydroxyl group, still matters...
alkyl ethers: CH3–(CH2)10–16–(O-C3H6)1–25–O - GlucosideGlucosideA glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes....
alkyl ethers: CH3–(CH2)10–16–(O-Glucoside)1–3–OH:- Decyl glucosideDecyl glucosideDecyl glucoside is a mild non-ionic surfactant used in cosmetic formularies including baby shampoo and in products for individuals with a sensitive skin...
, - Lauryl glucosideLauryl glucosideLauryl glucoside is a surfactant used in cosmetics. It is a glycoside produced from glucose and lauryl alcohol....
- Octyl glucosideOctyl glucosideOctyl glucoside is a detergent frequently used to dissolve integral membrane proteins for studies in biochemistry...
- Decyl glucoside
- Polyoxyethylene glycol octylphenol ethers: C8H17–(C6H4)–(O-C2H4)1–25–OH:
- Polyoxyethylene glycol alkylphenol ethers: C9H19–(C6H4)–(O-C2H4)1–25–OH:
- Nonoxynol-9Nonoxynol-9Nonoxynol-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...
- Nonoxynol-9
- GlycerolGlycerolGlycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids...
alkyl esters:- Glyceryl laurateGlyceryl laurateGlyceryl laurate, also glycerol monolaurate or monolaurin, is a monoglyceride surfactant. It is the mono-ester formed from glycerol and lauric acid. Its chemical formula is C15H30O4.It is most commonly used in deodorants....
- Glyceryl laurate
- Polyoxyethylene glycol sorbitan alkyl esters: PolysorbatePolysorbatePolysorbates are a class of emulsifiers used in some pharmaceuticals and food preparation. They are often used in cosmetics to solubilize essential oils into water-based products. Polysorbates are oily liquids derived from PEG-ylated sorbitan esterified with fatty acids...
- Sorbitan alkyl esters: Spans
- Cocamide MEACocamide MEACocamide MEA, or cocamide monoethanolamine, is a solid, off-white to tan compound, often sold in flaked form. The solid melts to yield a pale yellow viscous clear to amber liquid...
, cocamide DEACocamide DEACocamide DEA, or cocamide diethanolamine, is a diethanolamide made by reacting the mixture of fatty acids from coconut oils with diethanolamine. It is a viscous liquid and is used as a foaming agent in bath products like shampoos and hand soaps, and in cosmetics as an emulsifying agent. See... - Dodecyldimethylamine oxide
- Block copolymers of polyethylene glycol and polypropylene glycol: PoloxamerPoloxamerPoloxamers are nonionic triblock copolymers composed of a central hydrophobic chain of polyoxypropylene flanked by two hydrophilic chains of polyoxyethylene . The word "poloxamer" was coined by the inventor, Irving Schmolka, who received the patent for these materials in 1973...
s - Polyethoxylated tallow aminePolyethoxylated tallow aminePolyethoxylated tallow amine is a surfactant that enhances the activity of herbicides. It improves the solubility of many common herbicides in organic solvents, increasing their penetration of the waxy surfaces of plants. It may also interfere with the function of tadpole gills...
(POEA).
- Fatty alcohol
According to the composition of their counter-ion
In the case of ionic surfactants, the counter-ion can be:- Monoatomic / InorganicInorganic compoundInorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
:- Cations: metalMetalA metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
s : alkali metalAlkali metalThe alkali metals are a series of chemical elements in the periodic table. In the modern IUPAC nomenclature, the alkali metals comprise the group 1 elements, along with hydrogen. The alkali metals are lithium , sodium , potassium , rubidium , caesium , and francium...
, alkaline earth metalAlkaline earth metalThe alkaline earth metals are a group in the periodic table. In the modern IUPAC nomenclature, the alkaline earth metals are called the group 2 elements. Previously, they were called the Group IIA elements . The alkaline earth metals contain beryllium , magnesium , calcium , strontium , barium and...
, transition metalTransition metalThe term transition metal has two possible meanings:*The IUPAC definition states that a transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." Group 12 elements are not transition metals in this definition.*Some... - Anions: halideHalideA halide is a binary compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative than the halogen, to make a fluoride, chloride, bromide, iodide, or astatide compound. Many salts are halides...
s: chlorideChlorideThe chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
(Cl−), bromideBromideA bromide is a chemical compound containing bromide ion, that is bromine atom with effective charge of −1. The class name can include ionic compounds such as caesium bromide or covalent compounds such as sulfur dibromide.-Natural occurrence:...
(Br−), iodideIodideAn iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. This page is for the iodide ion and its salts. For information on organoiodides, see organohalides. In everyday life, iodide is most commonly encountered as a component of iodized salt,...
(I−)
- Cations: metal
- PolyatomicPolyatomic ionA polyatomic ion, also known as a molecular ion, is a charged species composed of two or more atoms covalently bonded or of a metal complex that can be considered as acting as a single unit in the context of acid and base chemistry or in the formation of salts. The prefix "poly-" means "many," in...
/ OrganicOrganic compoundAn 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...
:- Cations: ammonium, pyridiniumPyridiniumPyridinium refers to the cationic form of pyridine. This can either be due to protonation of the ring nitrogen or because of addition of a substituent to the ring nitrogen, typically via alkylation. The lone pair of electrons on the nitrogen atom of pyridine is not delocalized, and thus pyridine...
, triethanolamineTriethanolamineTriethanolamine, often abbreviated as TEA, is an organic chemical compound which is both a tertiary amine and a triol. A triol is a molecule with three alcohol groups. Like other amines, triethanolamine is a strong base due to the lone pair of electrons on the nitrogen atom. Triethanolamine can...
(TEA) - Anions: tosylTosylA tosyl group is CH3C6H4SO2. This group is usually derived from the compound 4-toluenesulfonyl chloride, CH3C6H4SO2Cl, which forms esters and amides of toluenesulfonic or tosylic acid...
s, trifluoromethanesulfonates, methylsulfate
- Cations: ammonium, pyridinium