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Surfactants are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids. For the work of fiction see Surface Tension (short story. Surface tension is a property of the surface of a Liquid that causes it to For the work of fiction see Surface Tension (short story. Surface tension is a property of the surface of a Liquid that causes it to

Contents

Etymology

The term 'surfactant' is a blend of "surface acting agent". In Linguistics, a blend is a word formed from parts of two other words Surfactants are usually organic compounds that are amphiphilic, meaning they contain both hydrophobic groups (their "tails") and hydrophilic groups (their "heads"). An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. Amphiphile (from the Greek αμφις amphis both and φιλíα Philia: love friendship is a term describing a Chemical compound possessing both In Chemistry, hydrophobicity (from the combining form of water in Attic Greek hydro- and for fear phobos) refers to the physical property of Hydrophile, from the Greek (hydros "water" and φιλια (philia "friendship" refers to a physical property of a Molecule Therefore, they are soluble in both organic solvents and water. The term surfactant was coined by Antara Products in 1950.

In Index Medicus and the United States National Library of Medicine, "surfactant" is reserved for the meaning pulmonary surfactant (see "alveoli" link below). Index Medicus (IM was a comprehensive index of medical journal articles published between 1879 and 2004 The United States National Library of Medicine ( NLM) operated by the United States federal government, is the world's largest Medical library. For the more general meaning, "surface active agent" is the heading.

The most common biological example of surfactant is that coating the surfaces of the Alveoli, the small air sacs of the lungs that serve as the site of gas exchange.

Operation and effects

A micelle - the lipophilic ends of the surfactant molecules dissolve in the oil, while the hydrophilic charged ends remain outside, shielding the rest of the hydrophobic micelle
A micelle - the lipophilic ends of the surfactant molecules dissolve in the oil, while the hydrophilic charged ends remain outside, shielding the rest of the hydrophobic micelle

Surfactants reduce the surface tension of water by adsorbing at the liquid-gas interface. Lipophilicity, fat-liking, refers to the ability of a Chemical compound to dissolve in fats oils lipids and non-polar solvents such as Hexane or Hydrophile, from the Greek (hydros "water" and φιλια (philia "friendship" refers to a physical property of a Molecule Adsorption is a process that occurs when a gas or liquid Solute accumulates on the surface of a solid or a liquid (adsorbent forming a film of molecules or atoms (the They also reduce the interfacial tension between oil and water by adsorbing at the liquid-liquid interface. Many surfactants can also assemble in the bulk solution into aggregates. In Chemistry, a solution is a Homogeneous Mixture composed of two or more substances Examples of such aggregates are vesicles and micelles. A micelle (rarely micella, plural micelles) is an aggregate of Surfactant molecules dispersed in a liquid Colloid. The concentration at which surfactants begin to form micelles is known as the critical micelle concentration or CMC. A micelle (rarely micella, plural micelles) is an aggregate of Surfactant molecules dispersed in a liquid Colloid. In Chemistry, the critical micelle concentration ( CMC) is defined as the concentration of Surfactants above which Micelles are spontaneously When micelles form in water, their tails form a core that can encapsulate an oil droplet, and their (ionic/polar) heads form an outer shell that maintains favorable contact with water. When surfactants assemble in oil, the aggregate is referred to as a reverse micelle. In a reverse micelle, the heads are in the core and the tails maintain favorable contact with oil. Surfactants are also often classified into four primary groups; anionic, cationic, non-ionic, and zwitterionic (dual charge). A zwitterion (first part pronounced "tsvitter" from German " Zwitter " &mdash "hybrid" " Hermaphrodite " is a

Thermodynamics of the surfactant systems are of great importance, theoretically and practically. In Physics, thermodynamics (from the Greek θερμη therme meaning " Heat " and δυναμις dynamis meaning " This is because surfactant systems represent systems between ordered and disordered states of matter. Surfactant solutions may contain an ordered phase (micelles) and a disordered phase (free surfactant molecules and/or ions in the solution). A micelle (rarely micella, plural micelles) is an aggregate of Surfactant molecules dispersed in a liquid Colloid. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge

Ordinary washing up (dishwashing) detergent, for example, will promote water penetration in soil, but the effect would only last a few days (although many standard laundry detergent powders contain levels of chemicals such as sodium and boron, which can be damaging to plants, so these should not be applied to soils). A detergent (as a noun is a material intended to assist Cleaning. Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Boron (ˈbɔərɒn is a Chemical element with Atomic number 5 and the chemical symbol B. 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 gutters.

Applications and sources

Surfactants play an important role in many practical applications and products, including:

Surfactants are also naturally secreted by type II cells of the lung alveoli in mammals. A fire extinguisher is an Active fire protection device used to extinguish or control small fires often in emergency situations An alveolus (plural alveoli, from Latin alveolus, "little cavity" is an anatomical structure that has the form of a hollow cavity Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands

Classification

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. A zwitterion (first part pronounced "tsvitter" from German " Zwitter " &mdash "hybrid" " Hermaphrodite " is a

Some commonly encountered surfactants of each type include:

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 [1][2][3]. Cetylpyridinium chloride ( CPC) is a Cationic Quaternary ammonium compound in some types of Mouthwashes Toothpastes Lozenges Polyethoxylated Tallow amine is a Surfactant that enhances the activity of herbicides. Benzalkonium chloride, also known as alkyldimethylbenzylammonium chloride and ADBAC, is a mixture of alkylbenzyldimethylammonium chlorides of various even-numbered Benzethonium chloride is a synthetic Quaternary ammonium salt. A zwitterion (first part pronounced "tsvitter" from German " Zwitter " &mdash "hybrid" " Hermaphrodite " is a Cocamidopropyl betaine ( CAPB) is a Zwitterionic Surfactant with a Quaternary ammonium cation in its molecule Poloxamers, also known by the trade name Pluronics are nonionic triblock Copolymers composed of a central Hydrophobic chain of polyoxypropylene (poly(propylene Fatty alcohols are Aliphatic Alcohols derived from natural Fats and Oils originating in plants but also synthesized in animals and Algae Cetyl alcohol, also known as 1-hexadecanol and palmityl alcohol, is a solid Organic compound with the Chemical formula CH3(CH215OH Oleyl alcohol, octadecenol, or cis-9-octadecen-1-ol, is a Fatty alcohol coming from inedible Beef Fat. Cocamide MEA, or cocamide monoethanolamine, is a pale yellow viscous clear to amber liquid or solid flakes Cocamide DEA, or cocamide diethanolamine, is a Diethanolamide made by reacting Fatty acids in Coconut oils with Diethanolamine. 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.

References

  1. ^ Detecting the transport of toxic pesticides from g...[Environ Toxicol Chem. 2008] - PubMed Result
  2. ^ Fate of glutaraldehyde in hospital wastewater and ...[Environ Int. 2005] - PubMed Result
  3. ^ [1]

External links

See also

Anti-fog agents also known as anti-fogging agents and treatments prevent the Condensation of Water on a surface in the form of small Droplets Cleavable detergents, also known as cleavable surfactants, are special Surfactants (detergents that are used in Biochemistry and especially in Proteomics

Dictionary

surfactant

-noun

  1. a surface active agent, or wetting agent, capable of reducing the surface tension of a liquid; typically organic compounds having a hydrophilic "head" and a hydrophobic "tail"
  2. a lipoprotein in the tissues of the lung that reduces surface tension and permits more efficient gas transport
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