Surfactants enhance foam stability

2023-03-15 16:50:06

After surfactants form micelles in aqueous solution, they have the ability to significantly increase the solubility of insoluble or slightly water-soluble organic compounds, and the solution is transparent. This effect is called solubilization. Aggregates of bubbles separated by liquid or solid films are called foams, which can be divided into liquid foams and solid foams. In liquid foams, the interface of liquid and gas plays a major role. Generally speaking, when the surface tension is low and the strength of the film is high, the foaming power is better whether it is a stable foam or an unstable foam. The viscosity of the solution plays a role in the stability of the foam in two aspects: one is to enhance the strength of the foam liquid film; in addition, the surface viscosity is high, and the film liquid is not easy to flow and discharge, which delays the rupture of the liquid film and enhances the stability of the foam.

For example, the anionic ones include condensed naphthalene sulfonate, lignosulfonate, condensed alkyl phenyl ether sulfate, etc. The cationic ones include amino alkyl acrylate copolymer, modified polyethylene imine, polyethylene benzyl trimethyl ammonium salt and so on. Amphoteric types include acrylic acid vinylpyridine copolymer, acrylic acid-cationic acrylate copolymer, amphoteric polyacrylamide, etc. Non-ionic types include hydroxyethyl cellulose, polyacrylamide, polyoxyethylene copolymers, etc.

Polymer surfactants can be classified into natural polymer surfactants and synthetic polymer surfactants according to their sources.

Natural polymer surfactants are amphiphilic water-soluble polymers that are separated and refined from animals and plants, including polymer surfactants made from natural polymers through chemical modification (also called semi-synthetic polymer surface active agents). active agent). Such as various starches, gums, polysaccharides, modified starches, cellulose, proteins and chitosan, etc. Synthetic polymer surfactants refer to polymers synthesized by homopolymerization of hydrophilic monomers or copolymerization with hydrophobic monomers. Such as polyacrylamide, polyacrylic acid and polystyrene-acrylic acid copolymer.