The following table provides the structure and properties of common surface active chemicals or surfactants (Refs. 1-2). These reagents are used industrially to decrease surface tension in many different applications, and they are used in the laboratory in many analytical and biochemical procedures, as well as consumer applications. In this way, the table complements many of the tables presented in Sections 7 and 8, in which these surfactants are incorporated in reagents. The table is arranged alphabetically according to chemical name, although the most common generic name or abbreviation is provided in bold type (unless the chemical name is also the most common name). The surfactant class is provided (anionic, cationic, or non-ionic). Anionic surfactants are molecules in which the hydrophilic moiety is a negatively charged group such as a sulfonate, sulfate, or carboxylate. Cationic surfactants are molecules in which the hydrophilic moiety is a positively charged group such as a quaternary ammonium ion. Non-ionic surfactants are molecules in which the hydrophilic moiety is uncharged, such as an ethoxylate. Another classification exists, though not represented here, called amphoteric surfactants, in which the ionic character is pH dependent.
When available, the melting and normal boiling temperatures are provided; if decomposition occurs before this state point is reached, this is indicated by the notation “dec.” The measured density of either the liquid or a solution is provided, along with temperature, whenever possible. The predicted density, while available for some surfactants in which measurements are unavailable, is not provided here.
When available, the critical micelle concentration (CMC), the concentration of the surfactant above which micelles spontaneously form, is provided. The preferred unit is mmol per liter (mmol L-1), but in the case of mixtures, this is provided as a percent or ppm, usually on the basis of mass (mass/mass). The CMC is dependent on temperature, the ionic strength of the solution, and, to some extent, the measurement technique. For anionic and cationic surfactants, the CMC is reduced by increasing ionic strength, but temperature has a minor effect. For non-ionic surfactants, the CMC is relatively insensitive to ionic strength, but increases as temperature increases. For the CMC values given here, the temperature is provided whenever possible. If not specified, the temperature is to be regarded as ambient.
When available, the aggregation number is provided (Refs. 3 and 4). This is the mean number of surfactant molecules present in a micelle after the CMC has been reached. It is measured using luminescent probes by varying surfactant concentration and is dependent on temperature and the concentration of organic or ionic species present. The hydrophilic lipophilic balance (HLB) is provided when available. This is a fit-for-purpose property rather than a fundamental property, which has evolved in definition and determination since being devised, a matter beyond the scope of this entry. The HLB is a numerical scale between 0 and 20 descriptive of the tendency of a surfactant to be either hydrophilic or hydrophobic. A relatively high HLB (greater than 10) indicates hydrophilicity, or good water or polar solvent solubility. A relatively low HLB (lower than 10) indicates lipophilicity, or good solubility in nonpolar solvents such as oils or organics. The HLB changes with concentration and mixture composition.
Column definitions for the table are as follows.
Column heading | Definition |
Name | Chemical name of surfactant; listed alphabetically; structure diagram is shown below name |
Synonym | Common synonyms |
Mol. form. | Molecular formula of surfactant, in Hill order |
Mol. wt. | Molecular weight |
tbp | Normal boiling point temperature (at 101.325 kPa), in °C |
tmp | Melting point, in °C |
ρ | Density, g cm-3 |
CMC | Critical micelle concentration, in units mmol L-1 (see discussion above) |
Aggr. no. | Aggregation number (see discussion above) |
HLB | Hydrophilic/hydrophobic tendency (see discussion above) |
Sol. H2O | Solubility in water |
Name | Synonym | Structure | Mol. form. | Mol. wt. | tbp/°C | tmp/°C | ρ/g cm-3 | CMC/mmol L-1 | Aggr. no. | HLB | Sol. H2O | Soluble in | Notes |
Anionic surfactants | |||||||||||||
Abietic acid | abietinic acid; sylvic acid; abieta-7,13-dien-18-oic acid (1R,4aR,4bR,10aR)-7-isopropyl-1,4a- dimethyl-1,2,3,4,4a,4b,5,6,10,10a-decahydrophenanthrene-1- carboxylic acid | ![]() | C20H30O2 | 302.451 | 439.5 | 173.5 | 1.0625 | 2 at 25 °C | Insoluble | ethanol, acetone, ether, chloroform, and benzene | Natural product is primary component of resin acid of pine wood; used as bow rosin; used at high pH. | ||
Bis(2-ethylhexyl) sodium sulfosuccinate | sodium dioctyl sulfosuccinate; dioctyl sulfosuccinate sodium salt; sodium 1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate; 1,4-bis (2-ethylhexyl) sodium sulfosuccinate; sulfosuccinic acid 1,4-bis (2-ethylhexyl) ester sodium salt; sulfobutanedioic acid 1,4-bis (2-ethylhexyl) ester sodium salt; dioctyl sodium sulfosuccinate; colace; ex-lax; senokot; comfolax | ![]() | C20H37NaO7S | 444.559 | dec | 155 | 1.125 | 15 g/L at 25 °C; 23 g/L at 40 °C; 30 g/L at 50 °C; 55 g/L at 70 °C | ethanol (20 g/L), chloroform (300 g/L), diethyl ether (300 g/L), petroleum ether (unlimited), glycerol, carbon tetrachloride, xylene, petroleum ether, acetone, and vegetable oils | Stable in acid and neutral solutions; hydrolyzes in basic media; used as emulsifier; dispersant, emulsifier, wetting agent, and laxative to treat constipation and earwax removal. | |||
Deoxycholic acid | (3α,5β,12α,20R)-3,12-dihydroxycholan-24-oic acid; cholanoic acid; deoxycholate; deoxycholic; Pyrochol; Septochol(l) | ![]() | C24H40O4 | 392.573 | dec | 177 | 5 at 25 °C | 22 | 17.6 | 0.24 mg/mL at 15 °C | ethanol (1 g/100 mL at 20 °C), acetone, ether, and chloroform | Readily dialyzable; used in a modified procedure to recover 40% - 80% of a protein; pKa = 6.58; λmax = 310 nm; specific rotation +55°; forms molecular coordination compounds; complexes with fatty acids; sodium salt is much more soluble (333 mg/mL in water at 15 °C), but its aqueous solutions precipitate at pH < 5. | |
Perfluorobutanesulfonic acid | FC-98; PFBS; nonaflate; 1,1,2,2,3,3,4,4,4- nonafluorobutanesulfonic acid; 1,1,2,2,3,3,4,4,4- nonafluorobutane-1-sulfonic acid; nonafluorobutanesulfonic acid; nonafluoro-1-butanesulfonic acid; nonafluorobutane-1-sulfonic acid; nonafluorobutanesulfonic acid; perfluorobutane sulfonate | ![]() | C4HF9O3S | 300.1 | 211 | ≈80 | 1.81125 | reacts violently | Used as a replacement for perfluoroctanesulfonic acid stain repellent. | ||||
Sodium dodecyl sulfate | sodium lauryl sulfate, SDS, sodium monododecyl sulfate; sodium lauryl sulfate; sodium monolauryl sulfate; sodium dodecanesulfate; sodium coco-sulfate; dodecyl alcohol, hydrogen sulfate, sodium salt; n-dodecyl sulfate sodium; sulfuric acid monododecyl ester sodium salt | ![]() | C12H25NaO4S | 288.380 | dec | 205 | 1.0625 | 8.2 at 25 °C | 62 | 40 | 200 mg/mL at 20 °C | ethanol | Aids in lysing cells during DNA extraction and for unraveling proteins in SDS-PAGE; low pKa; can be used in pH as low as 4; can be prone to foaming. |
Cationic surfactant | |||||||||||||
Cetyltrimethylammonium bromide | CTAB, CTABr, alkyltrimethylammonium bromide; HTAB; hexadecyl palmityltrimethylammonium bromide; palmityltrimethylammonium bromide | ![]() | C19H42N | 364.45 | dec | 240 | 0.92 – 1.00 at 25 °C | 75-170 | ≈10 | 0.3 g/100 mL at 20 °C | alcohols, slightly soluble in acetone; insoluble in diethyl ether and benzene | Aids in high molecular mass DNA isolation and PCR analysis; titrant for perchlorate; phase transfer catalyst in arene and heterocycle reductions. | |
Ionic (amphiphilic) surfactant | |||||||||||||
Sodium lauroyl sarcosinate | sarkosyl; sarkosyl NL; sodium N-lauroylsarcosinate; sarcosyl; sarcosyl NL; maprosyl 30; sodium [dodecanoyl(methyl)amino]acetate; n-lauroylsarcosine, sodium salt; N-methyl-N-(1-oxododecyl)glycine, sodium salt; sodium-n-lauriyl sarcosinate | ![]() | C15H28NNaO3 | 293.378 | dec | 140 | 7.0% - 8.6% mass/mass | White powder (94%); pH 7.5-8.5 (10% sol); foam stabilizer; lubricant; corrosion inhibitor; bacteriostat; used in emulsion polymerization. | |||||
Non-ionic surfactants | |||||||||||||
Dodecyl-β-D-maltoside | n-dodecyl-beta-D-maltopyranoside; dodecyl 4-O-alpha-D-glucopyranosyl-beta-D-glucopyranoside; dodecyl B-D-maltopyranoside | ![]() | C24H46O11 | 510.62 | dec | 225 | 1.2625 | 0.15 - 0.17 at 25 °C | 70-140 | ≈10 | soluble | Used to aid in the solubilization and isolation of hydrophobic membrane proteins to preserve their activity. | |
Ethoxylated tall oil | Ethofat242/25, Renex; Industrol TO 16HR; OKM; OKM (surfactant); OKM 10; OKM 12; OKM 50; OKM 60; OKM75; T 13; T 13 (emulsifier); Teric T 2 | Mixture | 945 | dec | 1.0825a | 4a at 25 °C | 12.2 | soluble | Derived from tall oil obtained from paper processing, can be used at wide range of pH. | ||||
Glycerol 1-dodecanoate, (±)- | glyceryl laurate, glycerol monolaurate; glycerol α-monolaurate; glycerin monolaurate; glycerol 1-laurate; glycerol 1-monolaurate; glycerol α- monolaurate; dodecanoic acid 2,3-dihydroxypropyl ester; 1-lauroyl-glycerol; monolauroylglycerin; 2,3-dihydroxypropyl dodecanoate; 2,3-dihydroxypropyl laurate; dodecanoic acid α-monoglyceride; 1-mono-dodecanoyl glycerol; lauricidin R; 1-monomyristin; imwitor 312; lauricidin 802; dimodan ML 90; monomuls L 90; monomuls 90L12 | ![]() | C15H30O4 | 274.397 | 397 | 63.2 | 12.67 mg/L at 25 °C | methanol and chloroform (50 mg/L) | White fluffy semisolid; has shown both antibacterial and antiviral activity in vitro; used against some infections but clinical studies are incomplete; used in deodorants and in some cases as an emulsifier in food additives; used as a methane mitigation agent in ruminants. | ||||
Octyl-β-D-1-thioglucopyranoside | (1S)-octyl-β-D-thioglucoside; n-octyl-β-D-thioglucoside; OTG; (2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-octylsulfanyl-oxane-3,4,5-triol; (2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-(octylthio)tetrahydro-2H-pyran-3,4,5-triol; octylthioglycoside; octyl thioglycoside; octyl-β-D-thioglucopyranoside | ![]() | C14H28O5S | 308.43 | dec | 128 | 9 at 25 °C | slightly soluble | ethanol (50 mg/mL) | Colorless powder; used for cell lysis and for solubilizing proteins without denaturing them; dialyzable. | |||
Polyethylene glycol tert-octylphenyl ether | Octoxynol-9, Triton X-100, TX-100 | ![]() | 647 | 270 | 6 | 1.0725 | 0.24 - 0.27 at 25 °C | 140 | 13.5 | soluble | benzene, toluene, xylene, trichloroethylene, ethylene glycol, ethyl ether, ethanol, isopropanol, and ethylene dichloride | Non-ionic surfactant and emulsifier widely used for solubilizing membrane proteins and lysing cells; no antimicrobial properties; absorbs in the UV, so can interfere with protein quantitation. | |
Polyoxyethylene (20) sorbitan monolaurate | Polysorbate 20; PEG(20) sorbitan monolaurate; Alkest TW 20; Tween 20 | ![]() | C58H114O26 | 1227.54 | dec | 1.0625 | 0.06 at 25 °C | 62 | 16.7 | soluble | Washing agent in immunoassay; lysing mammalian cells; used industrially in cleaning applications. | ||
Polyoxyethylene (20) sorbitan monooleate | Polysorbate 80; Alkest TW 80; Tween 80 | ![]() | C64H124O26 | 1310 | dec | 1.0725 | 0.0125 | 13.4-15 | soluble | Used to stabilize aqueous drug formulations; emulsifier for drugs; surfactant used in cosmetics and soaps, and in mouthwash, oily liquid. | |||
Tergitol | secondary alcohol ethoxylate | ![]() | dec | 1.00620 | 52 ppm (mass/mass) | soluble | chlorinated solvents and most polar organics (ethanol, acetone) | Pale yellow liquid; pH (1% aqueous solution) 7.1; chemically stable in the presence of dilute acids, bases, and salts; compatible with anionic, cationic, and other non-ionic surfactants; used in chemical analysis, high-performance cleaners and agrochemicals; member of the large Tergitol family of surfactants. |
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