What are the differences between surfactants and other additives, such as dispersants? In fact, surfactants are a broad category that includes many additives, and dispersants are also surfactants. However, it should be noted that inorganic dispersants are all surfactants, while inorganic dispersants are not surfactants. Next, we will understand their respective properties.
Surfactant is a chemical drug that can greatly reduce the surface tension of solvents (usually water) or liquid-liquid interface surface tension, change the surface state of the system, and thus achieve a series of effects such as long-lasting wetting and anti wetting, emulsification and demulsification, dispersion and coagulation, foaming and defoaming, and solubilization. The special function played by surfactants is called surface activity.
Dispersant is a chemical agent that promotes the uniform dispersion of material particles in a medium, forming a stable suspension. Dispersants are generally divided into two categories: inorganic dispersants and organic dispersants. Common inorganic dispersants include silicates (such as water glass) and alkali metal phosphates (such as sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate). Organic dispersants include triethylhexyl phosphate, sodium dodecyl sulfate, methyl pentanol, cellulose derivatives, polyacrylamide, guar gum, fatty acid polyethylene glycol ester, etc. It can also be said that dispersants are additives that can improve and enhance the dispersibility of solid or liquid materials. When grinding solid dyes, adding dispersants helps to pulverize the particles and prevent them from coalescing, thus maintaining the stability of the dispersion. Oil liquids that are insoluble in water can disperse into very small droplets under high shear force stirring. After stopping stirring, they quickly separate under the action of interfacial tension. However, after adding a dispersant and stirring, a stable emulsion can be formed. Its main function is to reduce the interfacial tension between liquid-liquid and solid-liquid.
In summary, dispersants are interfacial active agents that possess both lipophilic and hydrophilic properties within their molecules. It can uniformly disperse solid particles of inorganic and organic pigments that are difficult to dissolve in liquids, while also preventing the settling and aggregation of solid particles, forming the required agents for stable suspensions. Surfactants refer to substances with fixed hydrophilic and lipophilic groups that can be oriented and arranged on the surface of a solution, and can significantly reduce surface tension.
