Fluorinated surfactants containing silicon are attracting people's attention

2020-09-18 11:15:05

The traditional fluorine-containing surfactants are mainly single chain type. At present, double chain fluorinated surfactants are attracting great interest. There are two kinds of double chain fluorocarbon surfactants reported. The first type is that the double chain is fluorocarbon chain, and the second type is double chain, which is carbon fluorine and hydrocarbon chain respectively. The latter is often called hybrid surfactants.

In recent years, fluorinated surfactants containing silicon have attracted people's attention because of their unique properties. Both fluorine-containing surfactants and silicon surfactants belong to special surfactants. Fluorinated surfactants containing silicon are expected to have high surface activity in ethanol aqueous solution with high concentration. It can be used not only in aqueous system but also in non-aqueous system. The fluorinated surfactant containing silicon also has excellent lubricating effect. Some studies have also shown that silicon containing fluorinated surfactants have high anti HIV1 activity.

Great progress has also been made in the chemical modification of fluorocarbon chains in fluorinated surfactants to give them more special functions. In contrast to the zigzag configuration of the hydrocarbon chain, the fluorocarbon chain has a rigid configuration. Some people introduce ether bond into fluorocarbon chain to make it more flexible and water soluble. The introduction of heteroatoms makes the fluorocarbon chain more diversified. The history of fluorinated surfactant as an industrial product is not very long, and its application field needs to be further developed. With the gradual research and understanding of its performance and application, it is believed that the variety and output of this kind of product will continue to expand. Compared with foreign countries, there is still a big gap in the development, performance research and application fields of fluorinated surfactants in China. With the development of China's national economy and the continuous enhancement of comprehensive national strength, the development and application of this new product and new technology of fluorine-containing surfactant will present a broad prospect.

A surfactant in which the hydrogen atoms of the hydrocarbon chain in the surfactant molecule are completely or partially replaced by fluorine atoms.

Fluorinated surfactants can be called both fluorocarbon surfactants and fluorocarbon surfactants. Their unique properties can be summarized as "three high" and "two hydrophobic", that is, high surface activity, high thermal stability and high chemical stability. Its fluoroalkyl groups are both hydrophobic and oleophobic. The unique properties of fluorine surfactants are related to the properties of fluorine atoms and carbon fluorine bonds. First of all, because fluorine is a highly electronegative element, the bond energy of C-F bond is very high. Secondly, the radius of covalently bonded fluorine atom is larger than that of hydrogen atom, which can effectively protect perfluorinated C-C bond. Therefore, fluorine surfactants have high thermal and chemical stability.

The surface tension of its aqueous solution is usually lower than 20Mn / m, and it can not only reduce the surface tension of water, but also the surface tension of oil.

This kind of surfactant is stable in chemical property, resistant to acid, alkali and high temperature. It can be used as fire extinguishing agent of oil and water as well as evaporation inhibition of oil and water. The commonly used fluorinated surfactants are sodium perfluorooctanoate and sodium perfluorooctanesulfonate. Due to the high price, the application of these surfactants is limited.