what is a surfactant?

Answer 1

Surfactants are wetting agents that lower/relax the surface tension on liquids to allow easy spreading of the same.The term is a blend of the words "surface active agents" and is related to Etymology.

Answer 2

Surfactants are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids.

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 micelleSurfactants reduce the surface tension of water by adsorbing at the liquid-gas interface. 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. Some of these aggregates are known as micelles. The concentration at which surfactants begin to form micelles is known as the critical micelle concentration or CMC. When micelles form in water, their tails form a core that is like 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).

Thermodynamics of the surfactant systems are of great importance, theoretically and practically. 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).

Ordinary washing up 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). Commercial soil wetting agents will continue to work for a considerable period, but they will eventually be degraded by soil micro-organisms. They 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.
A surfactant can be classified by the presence of formally charged groups in its head. A nonionic 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 sulfate, sulfonate or carboxylate anions)
Sodium dodecyl sulfate (SDS), ammonium lauryl sulfate, and other alkyl sulfate salts
Sodium laureth sulfate, also known as sodium lauryl ether sulfate (SLES)
Alkyl benzene sulfonate
Soaps, or fatty acid salts (see acid salts)
Cationic (based on quaternary ammonium cations)
Cetyl trimethylammonium bromide (CTAB) a.k.a. hexadecyl trimethyl ammonium bromide, and other alkyltrimethylammonium salts
Cetylpyridinium chloride (CPC)
Polyethoxylated tallow amine (POEA)
Benzalkonium chloride (BAC)
Benzethonium chloride (BZT)
Zwitterionic (amphoteric)
Dodecyl betaine
Dodecyl dimethylamine oxide
Cocamidopropyl betaine
Coco ampho glycinate
Nonionic
Alkyl poly(ethylene oxide)
Alkyl polyglucosides, including:
Octyl glucoside
Decyl maltoside
Fatty alcohols
Cetyl alcohol
Oleyl alcohol

Answer 3

This website will help:
http://en.wikipedia.org/wiki/Surfactant

Answer 4

A substance that lowers surface tension of a liquid

Answer 5

It is a lubricant that your body creates to reduce the friction associated with lung expansion inside the thorasic cavity

Answer 6

any substance that when dissolved in water or an aqueous solution reduces its surface tension or the interfacial tension between it and another liquid.