The fluorosurfactant mainly refers to a surfactant in which hydrogen on the hydrophobic group of the hydrocarbon chain is completely replaced by a fluorine atom. Surfactants containing a fluorocarbon chain hydrophobic group have a unique series of interfacial activities as compared with the aforementioned surfactants, and are widely used in various lubricants, etchants, additives, and surface treatment agents.
The characteristics of the fluorosurfactant are the same as those of the surfactant having a hydrocarbon chain hydrophobic group. The fluorosurfactant can be classified into anionic, cationic, zwitterionic and nonionic surfactants according to the structure of the hydrophilic group. The structure of the hydrophilic group is not different from that of the hydrocarbon surfactant.
Therefore, the characteristics of the fluorosurfactant are determined by the fluorocarbon chain. Table 1-1 lists some properties of fluorine atoms, hydrogen atoms and chlorine atoms. Since the electronegativity of fluorine is large, the C-F bond has a large bond energy, so the chemical stability and thermal stability of the carbon fluoride chain are high. In addition, the radius of the fluorine atom is larger than that of the hydrogen atom, and the carbon atom can be completely covered; in addition, the van der Waals force is small, that is, the intermolecular force is small.
For these reasons, the fluorocarbon chain has the following characteristics: 1 due to the large bond energy of the fluorocarbon bond, its thermal stability and reagent resistance are good, and the toxicity is small; 2 due to the small intermolecular force, the surface tension is small, The water is simmered and oily, the friction coefficient is small, and it is not adhered; 3 is small in refractive index; 4 is high in insulation performance.
