Fluoro surfactant and surface treatment agent

Fluorine surfactants and surface treatment agents

Fluorine surfactant

Fluorine surfactants are surfactants with fluorocarbon chains as non-polar groups, which partially or completely replace hydrogen atoms on carbon and hydrogen chains with fluorine atoms. Fluorocarbon surfactants have high surface activity, high thermal and chemical stability. As is well known, surfactants are generally composed of two parts: polar groups (hydrophilic groups) and non-polar groups (hydrophobic groups). The non-polar group of ordinary surfactants is a hydrocarbon chain, while the non-polar group of fluorocarbon surfactants is a fluorocarbon chain, which partially or completely replaces the hydrogen atoms on the hydrocarbon chain with fluorine atoms. When fluorine atoms replace hydrogen atoms, the surface activity of fluorine exhibits some excellent properties. If it has strong surface activity, it can reduce the surface tension of liquids such as water from 70dyne/cm to below 20dyne/cm, making it widely used in different fields. For example, in the field of water film fire extinguishing, fluorine surface activity can reduce the surface tension of water, thereby spreading on oil, achieving the purpose of isolating oxygen and extinguishing fire. In the field of coatings, fluorine surfactants can provide extremely low surface tension, thereby achieving wetting and leveling functions. At present, fluorine surface activity has been widely used in fire fighting foam, coating, agricultural greenhouse film, etc.

Like ordinary surfactants, fluorocarbon surfactants can be classified into two categories based on their polar group structures: ionic and non-ionic. Ionic fluorocarbon surfactants can be divided into anionic, cationic, and zwitterionic types.

1. Anionic fluorocarbon surfactants:

According to their different polar groups (hydrophilic groups), they can be divided into carboxylate salts (RfCOO-M), sulfonate salts (RfSO3-M), phosphate salts (RfOPO3M), and sulfate salts (RfOSO3-M), with the former being mainly used in industry.

Carboxylate fluorocarbon surfactants: generally have lower solubility in strong acids or aqueous solutions containing high valence cations, but higher thermal stability;

Sulfonate fluorocarbon surfactants: relatively better oxidation resistance, less sensitivity to strong acids and electrolytes;

Phosphate fluorocarbon surfactants: relatively poor foaming performance.

2. Cationic fluorocarbon surfactants:

Cationic fluorocarbon surfactants are almost all nitrogen-containing compounds, namely organic amine derivatives. Due to the negative charge on the surface particles of most substances, cationic surfactants are easily adsorbed.

3. Amphoteric fluorocarbon surfactants:

The molecular structure of zwitterionic surfactant contains both acidic and basic groups, and its main structure is betaine type structure. This surfactant has very low surface tension and is widely used in aqueous film forming foam extinguishing agent.

4. Nonionic fluorocarbon surfactants:

Nonionic fluorocarbon surfactants do not ionize in aqueous solutions, and their polar groups are usually oxygen-containing ether bonds (such as polyoxyethylene). Non ionic surfactants are more soluble in water and organic solvents (including acidic and alkaline media) than other types of surfactants, and have better compatibility with other types of surfactants. Due to its non ionization in water, it has high pH stability and is less affected by electrolytes and inorganic salts.

Fluorine surface treatment agents are based on fluoropolymers, which endow the surface of the treated object with extremely low surface tension after treatment, allowing it to resist various liquids such as water and oil. This fluorine treatment agent is widely used in the surface treatment of textiles, paper, leather, stone and other objects. While maintaining the appearance of the object itself, it exhibits excellent water repellent, oil repellent and anti fouling effects.