An antistatic agent is a compound used for treatment of materials or their surfaces in order to reduce or eliminate buildup of
static electricity. Static charge may be generated by the
triboelectric effect
The triboelectric effect (also known as triboelectric charging) is a type of contact electrification on which certain materials become electrically charged after they are separated from a different material with which they were in contact. Rubb ...
or by a non-contact process using a high voltage power source. Static charge may be introduced on a surface as part of an in-mold label printing process.
The role of an antistatic agent is to make the surface or the material itself slightly
conductive
In physics and electrical engineering, a conductor is an object or type of material that allows the flow of charge (electric current) in one or more directions. Materials made of metal are common electrical conductors. Electric current is gene ...
, either by being conductive itself, or by absorbing
moisture
Moisture is the presence of a liquid, especially water, often in trace amounts. Small amounts of water may be found, for example, in the air (humidity), in foods, and in some commercial products. Moisture also refers to the amount of water vapo ...
from the air; therefore, some
humectants can be used. The molecules of an antistatic agent often have both
hydrophilic
A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press.
In contrast, hydrophobes are ...
and
hydrophobic
In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water.
Hydrophobic molecules tend to be nonpolar and, t ...
areas, similar to those of a
surfactant; the hydrophobic side interacts with the surface of the material, while the hydrophilic side interacts with the air moisture and binds the water molecules.
Internal antistatic agents are designed to be mixed directly into the material, external antistatic agents are applied to the surface.
Common antistatic agents are based on long-chain
aliphatic
In organic chemistry, hydrocarbons ( compounds composed solely of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. ''aleiphar'', fat, oil). Aliphatic compounds can be saturated, like hexane, ...
amine
In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen
Hydrogen is the chemical element wi ...
s (optionally
ethoxylated) and
amide
In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it i ...
s,
quaternary ammonium
In chemistry, quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure , R being an alkyl group or an aryl group. Unlike the ammonium ion () and the primary, secondary, or tertiary ammonium cations ...
salts (e.g.,
behentrimonium chloride
Behentrimonium chloride, also known as docosyltrimethylammonium chloride or BTAC-228, is a yellow waxlike organic compound with chemical formula , used as an antistatic agent and, sometimes, a disinfectant. It is commonly found in cosmetics su ...
or
cocamidopropyl betaine
Cocamidopropyl betaine (CAPB) is a mixture of closely related organic compounds derived from coconut oil and dimethylaminopropylamine. CAPB is available as a viscous pale yellow solution and it is used as a surfactant in personal care products ...
),
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...
s of
phosphoric acid
Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, w ...
,
polyethylene glycol
Polyethylene glycol (PEG; ) is a polyether compound derived from petroleum with many applications, from industrial manufacturing to medicine. PEG is also known as polyethylene oxide (PEO) or polyoxyethylene (POE), depending on its molecular we ...
esters, or
polyol
In organic chemistry, a polyol is an organic compound containing multiple hydroxyl groups (). The term "polyol" can have slightly different meanings depending on whether it is used in food science or polymer chemistry. Polyols containing two, thr ...
s. Traditional migrating antistatic agents include long-chain alkyl phenols, ethoxylated amines, and glycerol esters, such as
glycerol monostearate
Glycerol monostearate, commonly known as GMS, is a monoglyceride commonly used as an emulsifier in foods. It takes the form of a white, odorless, and sweet-tasting flaky powder that is hygroscopic. Chemically it is the glycerol ester of stearic ...
. Migrating antistatic agents offer cost-effective protection for short-term applications, but other applications need longer-term protection or the lower resistivity required to prevent sparks and protect electronics from electrostatic dissipation. These applications utilize permanent antistatic agents or conductive additives such as carbon black, conductive fibers, and nanomaterials. An antistatic agent for the treatment for coatings may also involve an ionic liquid or a solution of a salt in an ionic liquid.
Indium tin oxide Indium tin oxide (ITO) is a ternary composition of indium, tin and oxygen in varying proportions. Depending on the oxygen content, it can be described as either a ceramic or an alloy. Indium tin oxide is typically encountered as an oxygen-saturated ...
can be used as transparent antistatic coating of windows. It is also possible to use
conductive polymer
Conductive polymers or, more precisely, intrinsically conducting polymers (ICPs) are organic polymers that conduct electricity. Such compounds may have metallic conductivity or can be semiconductors. The biggest advantage of conductive polymers ...
s, like
PEDOT:PSS and conducting polymer nanofibers, particularly
polyaniline
Polyaniline (PANI) is a conducting polymer and organic semiconductor of the semi-flexible rod polymer family. The compound has been of interest since the 1980s because of its electrical conductivity and mechanical properties. Polyaniline is one of ...
nanofiber
Nanofibers are fibers with diameters in the nanometer range (typically, between 1 nm and 1 μm). Nanofibers can be generated from different polymers and hence have different physical properties and application potentials. Examples of natural polyme ...
s. In general these systems are not very durable for coating, especially antimony tin oxide is used for durable systems, often in its nano form, it is then formulated to a final coating.
Antistatic agents are also added to some military
jet fuels, and to
nonpolar
In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end.
Polar molecules must contain one or more polar ...
organic solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...
s, to impart electrical conductivity to them and avoid buildup of static charge that could lead to sparks igniting fuel vapors. Stadis 450 is the agent added to some
distillate fuel
Fuel oil is any of various fractions obtained from the distillation of petroleum (crude oil). Such oils include distillates (the lighter fractions) and residues (the heavier fractions). Fuel oils include heavy fuel oil, marine fuel oil (MFO), bun ...
s, commercial
jet fuels, and to the military
JP-8
JP-8, or JP8 (for "Jet Propellant 8") is a jet fuel, specified and used widely by the US military. It is specified by MIL-DTL-83133 and British Defence Standard 91-87, and similar to commercial aviation's Jet A-1, but with the addition of corrosi ...
. Stadis 425 and Dorf Ketal's SR 1795 are similar compounds, for use in distillate fuels. Statsafe products are used in non-fuel applications. Antis DF3, similar to Stadis 425, is an amber-colored liquid composed of polyamine and polysulfone. Oil-soluble
sulfonic acids, e.g.
dodecylbenzenesulfonic acid
Alkylbenzene sulfonates are a class of anionic surfactants, consisting of a hydrophilic sulfonate head-group and a hydrophobic alkylbenzene tail-group. Along with sodium laureth sulfate, they are one of the oldest and most widely used synthetic ...
, can be also used as part of some antistatic additives.
Antistatic agents can be added to nonpolar solvents to increase their conductivity to allow electrostatic
spray painting
Spray painting is a painting technique in which a device sprays coating material (paint, ink, varnish, etc.) through the air onto a surface. The most common types employ compressed gas—usually air—to atomize and direct the paint particles.
...
. (Oxygenated solvents have too high conductivity to be used here.)
The polysulfones can be prepared by reacting
olefins, notably
alpha-olefin
In organic chemistry, alpha-olefins (or α-olefins) are a family of organic compounds which are alkenes (also known as olefins) with a chemical formula , distinguished by having a double bond at the primary or alpha (α) position.''Petrochemical ...
s, with
sulfur dioxide. The polyamines can be prepared by reacting
epichlorohydrin with aliphatic monoamines.
See also
*
Antistatic device
References
{{DEFAULTSORT:Antistatic Agent
Electrostatics
Cleaning product components
Process chemicals