Views: 0 Author: Site Editor Publish Time: 2026-05-22 Origin: Site
Surfactants are amphiphilic molecules with unique interfacial adsorption and micellization properties in aqueous solutions. By positive adsorption, they rapidly reduce the surface tension of water to realize wetting and penetration. Through micellization, they form abundant micelles, lower interfacial tension between phases, and achieve emulsification, dispersion, foaming, and solubilization. Detergency represents the comprehensive performance of the above functions. This paper systematically introduces the six fundamental functions of surfactants and their application mechanisms.
Wetting refers to the process where one fluid displaces another on a solid surface. In textile dyeing and finishing, it mainly means water replaces air on fiber surfaces. Surfactants significantly reduce water surface tension, enabling rapid spreading and penetration into porous structures such as fabrics, thus improving capillary effect. Surfactants used for this purpose are called wetting agents or penetrants. Typical products include Penetrant JFC, Penetrant T, and Pull-open Powder BX. Suitable molecular structure, moderate HLB value, and good chemical stability are essential for high-efficiency wetting agents.
Emulsification is the process of dispersing one immiscible liquid into another in the form of microdroplets. The addition of surfactants reduces oil–water interfacial tension and forms a mechanically strong interfacial film to prevent coalescence. Emulsions are mainly divided into oil-in-water (O/W) and water-in-oil (W/O) types. Hydrophilic emulsifiers tend to form O/W emulsions, while lipophilic emulsifiers favor W/O emulsions. Common emulsifiers include Peregal O series, Span-Tween series, and EL emulsifier.
Dispersion is the process of uniformly distributing insoluble solid fine particles in a liquid. Dispersants must provide sufficient wettability, reduce solid–liquid interfacial tension, and form a stable protective layer on particle surfaces to avoid aggregation. Compared with emulsions, dispersions are more thermodynamically unstable and are usually prepared for immediate use. Dispersants are widely used in disperse dyes and vat dye systems. Representative products include Dispersing Agent NNO and Dispersant WA.
Foaming is the process of dispersing gas in a liquid to form a stable foam system. Surfactants adsorb on the bubble surface to form a compact liquid film, reduce drainage speed, and inhibit bubble merging, thereby stabilizing foam. Foam helps suspend and remove dirt and is applied in foam dyeing and foam printing. In most dyeing and finishing processes, defoaming and antifoaming are required to ensure process stability.
Solubilization is the phenomenon where poorly soluble substances enter surfactant micelles to form a transparent, thermodynamically stable homogeneous solution. Different from emulsification and dispersion, solubilization belongs to a stable monophasic system. It effectively improves the solubility and stability of dyes, silicone softeners, and other additives. The solubilization capacity depends on micelle concentration and micelle structure.
Detergency is the comprehensive effect of wetting, emulsification, dispersion, solubilization, and mechanical force. It reduces the binding force between dirt and substrate, detaches dirt, and prevents redeposition. Anionic and nonionic surfactants are the most commonly used detergent components. Typical products include Detergent AES, LAS, AS, and LS. Detergent efficiency is affected by concentration, temperature, pH value, fabric type, and mechanical action.
