Characteristics and Applications of Fluorosurfactants

1 Introduction

The fluorosurfactants (fluorine-containing surfactants) are the most important species of special surfactants, and have many irreplaceable applications of hydrocarbon surfactants. The fluorine-containing surfactant mainly uses a perfluoroalkyl group, a perfluoroalkenyl group, or a partially fluorinated alkyl group as a hydrophobic group portion, and then introduces an appropriate linking group and a hydrophilic group. By introducing different types of hydrophilic groups, different types of fluorosurfactant products such as anionic surfactants, cationic surfactants, nonionic surfactants and amphoteric surfactant products can be prepared.

2 Characteristics of fluorosurfactants

Fluorosurfactants have high surface activity, high heat stability and high chemical stability. The fluorocarbon groups of fluorine-containing surfactants are both hydrophobic and lipophobic. The minimum surface tension of the aqueous solution containing fluorosurfactant can reach below 20 mN/m, even to about 15 mN/m. Fluorosurfactants have outstandingly high surface activity so that their aqueous solutions can spread on the surface of hydrocarbon oils. Fluorosurfactants have high heat resistance. For example, solid potassium perfluoroalkyl sulfonate will decompose when heated above 420?, so it can be used at temperatures above 300?. Fluorosurfactants have high chemical stability, can resist the action of strong oxidants, strong acids and strong bases, and can still maintain good surface activity in their solutions. Studies have shown that the high surface activity of fluorosurfactants is caused by the low van der Waals force between the molecules.

3 Applications of fluorosurfactants

3.1 Application of fluorosurfactants in textile industry

Treating the fabric with a fluoroalkyl compound can impart excellent water and oil repellency to the fabric. The fluorine-containing fabric finishing agent has high stability under strong acid, strong alkali, high temperature and high radiation. In addition, the fluorine-containing fabric finishing agent has the characteristics of low concentration and high effect, and the fabric treated by the fluorine-containing fabric finishing agent maintains good air permeability and moisture permeability. Compared with other types of finishing agents, fluorine-containing fabric finishing agents have incomparable advantages in terms of water and oil repellency, stain resistance, washability, friction resistance, and corrosion resistance. Fluorine-containing fabric finishing agents can be divided into water-repellent and oil-repellent agents, soil retardants and soil-releasing finishing agents, etc.

3.2 Application of fluorosurfactants in paper industry

Fluorosurfactants play an important role in the preparation of paper coatings.

1. Dispersant: Dispersant is one of the most important additives in paper coatings. Fluorosurfactants are often used as high-solid coating dispersants for paper, giving paper coatings good fluidity and adaptability, and improving the miscibility of film-forming substances and pigments.

2. Antifoaming agent: Fluorosurfactant also acts as an antifoaming agent. It has a better defoaming effect on paper coatings than general defoamers.

3. Lubricant: Because the fluorine-containing surfactant has excellent lubricating and antistatic properties, it is an ideal material as a lubricant for paper coating. Paper treated with silicon surfactants can only be waterproof and not oil resistant. Fluorine-containing surfactants are both water- and oil-repellent, so they are ideal water-proof and oil-proof finishing agents for paper.

3.3 Application of fluorosurfactants in metal industry

Before processing of metal materials, the surface oxide layer and oil must be removed. Adding a small amount of fluorosurfactant to the pickling solution not only can quickly remove rust and maintain the surface flatness, but also has a certain corrosion protection effect on the metal, which can significantly improve the cleaning effect. Fluorosurfactants can be used as metal preservatives and metal gloss treatment agents. Adding fluorosurfactant to the plating solution can improve the quality of the plating layer.

3.4 Application of fluorosurfactants in coating and ink industry

Fluorosurfactants can improve the performance of pigments, coatings, inks, varnishes and adhesives at very low concentrations. For example, Fluorosurfactants can significantly improve the leveling properties of coatings and obtain a more uniform coating film, which can prevent consolidation and improve dispersibility. Adding fluorosurfactants to coatings and inks can reduce their surface tension, improve wettability, prevent the generation of air bubbles, and also make them have good water resistance.

4 Conclusion

Fluorosurfactant has not been used as an industrial product for a long time, and its application field needs to be further developed. With the in-depth study of the performance and application of fluorosurfactants, the variety and output of such products will surely continue to expand.

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