Surfactants are a class of chemical substances with specific molecular structures, also known as surfactants. They exhibit activity and adsorption behavior on the liquid surface or liquid interface. The principle of action of surfactants mainly involves the following aspects:
Reducing surface tension: Surfactants can reduce the surface tension of liquids, making it easier for liquids to unfold on the surface. This is because the molecules of surfactants have both hydrophilicity (interacting with water) and hydrophobicity (repelling non-polar substances). On the surface of a liquid, surfactant molecules tend to arrange into an adsorption layer, reducing the surface tension of the liquid, which is conducive to various phenomena such as emulsification, dispersion, wetting, etc.
Dispersion and emulsification: surfactants can disperse non-polar substances (such as oil) into water or water into non-polar substances to form a dispersion system or lotion. This is due to the presence of both hydrophilic and hydrophobic groups in the molecular structure of surfactants, allowing them to interact with water and non-polar substances simultaneously and form stable structures at their interfaces, thereby dispersing the two.
Wetting effect: Surfactants can reduce the contact angle between liquid and solid surfaces, making it easier for the liquid to unfold on the solid surface. This is because surfactants can change the interaction force between liquid and solid surfaces, enabling better contact between liquid and solid, and improving wetting performance. This is of great significance for applications such as coatings, cleaning agents, and dyes.
Penetration and cleaning effects: Surfactants can penetrate into surfaces such as dirt or grease, reducing their interaction with the substrate, making it easier to clean. The molecular structure of surfactants contains both hydrophilic and hydrophobic groups, which makes them have good oil-water compatibility and can effectively disperse and dissolve organic substances such as oil and dirt, achieving a cleaning effect.
In summary, surfactants play important functions and applications by reducing surface tension, dispersing emulsification, wetting, and penetrating cleaning, and are widely used in many fields such as detergents, emulsifiers, coatings, pharmaceuticals, and so on.