Hexadecyltrimethylammonium bromide
Encyclopedia
Cetrimonium bromide is one of the components of the topical antiseptic
cetrimide. The cetrimonium
(or hexadecyltrimethylammonium) cation is an effective antiseptic agent against bacteria and fungi.
It is a cationic surfactant
. Its uses include providing a buffer solution for the extraction of DNA
. It has been widely used in synthesis of gold nanoparticle
s (e.g., spheres, rods, bipyramids). It is also widely used in hair conditioning products.
As any surfactant
, it forms micelle
s in aqueous solutions. At 303 K (30 °C) it forms micelles with aggregation number
75-120 (depending on method of determination, usually average ~95) and degree of ionization α (fractional charge) 0.2 - 0.1 (from low to high concentration).
The standard constant of Br- counterion binding to the micelle at 303 K (30 °C) is K° ≈ 400. This value is calculated from Br- and CTA+ ion selective electrode
measurements and conductometry data by using literature data for micelle size (r = ~3 nm), extrapolated to the critical micelle concentration
. However, it varies with total surfactant concentration so it is extrapolated to the point at which the concentration of micelles is zero).
The closely related compounds cetrimonium chloride
and cetrimonium stearate are also used as topic antiseptics, and may be found in many household products such as shampoos and cosmetics,
while cetrimonium bromide, due to its high cost, is only found in select cosmetics.
Antiseptic
Antiseptics are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction...
cetrimide. The cetrimonium
Cetrimonium
Cetrimonium, cetyl trimethylammonium, or hexadecyltrimethylammonium is a quaternary ammonium cation whose salts are used as antiseptics:* Cetrimonium bromide * Cetrimonium chloride...
(or hexadecyltrimethylammonium) cation is an effective antiseptic agent against bacteria and fungi.
It is a cationic 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...
. Its uses include providing a buffer solution for the extraction of DNA
DNA extraction
DNA isolation is a routine procedure to collect DNA for subsequent molecular or forensic analysis. There are three basic and two optional steps in a DNA extraction:...
. It has been widely used in synthesis of gold nanoparticle
Nanoparticle
In nanotechnology, a particle is defined as a small object that behaves as a whole unit in terms of its transport and properties. Particles are further classified according to size : in terms of diameter, coarse particles cover a range between 10,000 and 2,500 nanometers. Fine particles are sized...
s (e.g., spheres, rods, bipyramids). It is also widely used in hair conditioning products.
As any 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...
, it forms micelle
Micelle
A micelle is an aggregate of surfactant molecules dispersed in a liquid colloid. A typical micelle in aqueous solution forms an aggregate with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic single tail regions in the micelle centre. This phase is...
s in aqueous solutions. At 303 K (30 °C) it forms micelles with aggregation number
Aggregation number
An aggregation number is a description of the number of molecules present in a micelle once the critical micelle concentration has been reached....
75-120 (depending on method of determination, usually average ~95) and degree of ionization α (fractional charge) 0.2 - 0.1 (from low to high concentration).
The standard constant of Br- counterion binding to the micelle at 303 K (30 °C) is K° ≈ 400. This value is calculated from Br- and CTA+ ion selective electrode
Ion selective electrode
An ion-selective electrode , also known as a specific ion electrode , is a transducer that converts the activity of a specific ion dissolved in a solution into an electrical potential, which can be measured by a voltmeter or pH meter. The voltage is theoretically dependent on the logarithm of the...
measurements and conductometry data by using literature data for micelle size (r = ~3 nm), extrapolated to the critical micelle concentration
Critical micelle concentration
In colloidal and surface chemistry, the critical micelle concentration is defined as the concentration of surfactants above which micelles form and almost all additional surfactants added to the system go to micelles....
. However, it varies with total surfactant concentration so it is extrapolated to the point at which the concentration of micelles is zero).
The closely related compounds cetrimonium chloride
Cetrimonium chloride
Cetrimonium chloride is a topical antiseptic. It is also commonly used in hair conditioners and shampoos, as a conditioning agent.- References:...
and cetrimonium stearate are also used as topic antiseptics, and may be found in many household products such as shampoos and cosmetics,
while cetrimonium bromide, due to its high cost, is only found in select cosmetics.