The commonly used surfactants are low molecular weight compounds with a molecular weight of several hundred. With the in-depth research in many hot areas, such as enhanced oil recovery, drug carriers and controlled release, biological simulation, polymer LB films, medical polymer materials (anticoagulant), lotion polymerization, etc., the requirements for surfactants are becoming increasingly diversified and high-performance, and surfactant polymers have become the focus of attention.

1.Polysoap

Most polysoaps are electrically charged, similar to polyelectrolytes. In fact, most polysoap is the product of hydrophobic modification of polyelectrolytes and is generally insoluble in water. The polysoap that has been synthesized so far includes the following types (R in the formula all represent long-chain alkyl groups):

  2.Water-soluble polymer surfactant

Polymer surfactants that do not form micelles in solution are generally mainly water-soluble polymer surfactants. According to their sources, they are divided into three categories: natural, semi-synthetic and synthetic polymer surfactants.

Natural polymers such as our common various gums, starch, microbial fermented polysaccharides, etc.;

Semi-synthetic polymers are various polymers obtained by chemical modification of starch, cellulose, and protein, such as cationic starch, methyl cellulose, etc.;

Synthetic polymers are polymers obtained by polymerizing petrochemical-derived polymer monomers, such as polyacrylamide derivatives, polyacrylic acid, etc.

Classification of polymer surfactants

According to its ionicity in water, it can be divided into anionic, cationic, zwitterionic and non-ionic.

Anionic polymer surfactant

(1) Carboxylic acid type Typical polymers include polyacrylic acid and its copolymers, crotonic acid and its copolymers, acrylic acid maleic anhydride copolymers and their partially saponified products, etc.

(2) Sulfate ester type. Typical polymers are:

(3) The sulfonic acid type includes partially sulfonated polystyrene, benzene sulfonic acid formaldehyde condensate, naphthalene sulfonic acid formaldehyde condensate, sulfonated polybutadiene, etc. Lignosulfonate is also a sulfonic acid type polymer. Surfactant. Typical sulfonic acid polymer surfactants include:

Cationic polymer surfactant

(1) Amine salts or polyamines such as polyethyleneimine, polyvinylpyrrolidone, polymaleimide and their derivatives, etc. Typical polymers are:

(2) Quaternary ammonium salts such as quaternized polyacrylamide, polyvinylpyridinium salt, polydimethylamine epichlorohydrin, etc. Quaternary ammonium polymer surfactants show positive properties in acidic, neutral and alkaline aqueous media. Representative products include:

Amphoteric polymer surfactant

The main varieties include acrylic vinyl pyridine copolymer, acrylic acid, cationic acrylate copolymer, amphoteric polyacrylamide, etc., such as:

Nonionic polymer surfactant

The main varieties include polyvinyl alcohol and its partially esterified or acetalized products, such as modified polyacrylamide, maleic anhydride copolymer, polyacrylate, polyether, polyethylene oxide-propylene oxide, Water-soluble phenolic resin, amino resin, etc.

Structure and properties of polymer surfactants

The surface activity of polymer surfactants depends on the macromolecule form in the solution, and the molecular form is closely related to factors such as the amphipathic chemical molecular structure of the polymer, composition ratio, and the relative molecular mass of the macromolecule.

Block surfactant

Multi-block hydrophobic segments are distributed on the macromolecule backbone. Appropriate hydrophobic and hydrophilic sequence lengths will effectively prevent the hydrophobic segments from associating themselves (forming single-molecule micelles) or intermolecular association (multi-molecule association).

Comb surfactant

Comb surfactants have the advantages of easy preparation and various varieties. For example, surfactants obtained by homopolymerization or copolymerization of amphoteric and amphiphilic monomers exhibit different branched chemical structures depending on the position of the hydrophobic and hydrophilic groups.

Due to the presence of hydrophilic groups on the branch chains, which hinders the aggregation and association of hydrophobic segments, even in the generated micelles, compared with the generally formed micelles with a tight core, the interior is quite loose and there are still a large number of water molecules. , so it can have high surface activity; at the same time, due to configuration reasons, the amphiphilic branch chain can hinder the association of the hydrophobic main chain composed of methylene and methine, allowing it to participate in interface adsorption. 

Studies have shown that, on the premise of maintaining solubility, any factor that increases the rigidity of the molecular chain is conducive to the stretching of macromolecules in the solution and may increase the surface activity of the polymer.

Application of polymer surfactants

Applications in the pharmaceutical industry

Due to the excellent surface activity of block and graft polymer surfactants, they are widely used in the pharmaceutical industry and can be used as drug carriers, drug emulsifiers, dispersion solubilizers, wetting agents, etc. In addition, polymer surfactants are used as phase transfer catalysts in drug synthesis and are also widely used in drug analysis.

Applications in the petroleum industry

Since the extracted crude oil contains solid paraffin, the fluidity of the crude oil is poor, which brings certain difficulties to the production, storage, transportation, and processing of this easily condensable and highly viscous oil. This problem can be solved by adding a crude oil pour point depressant or Liquidity improver solution. Utilizing the dispersion of oil-soluble polymer surfactants can further improve the fluidity improver and prevent paraffin in fuel oil from forming precipitation during transportation and storage.

Application in textile printing and dyeing industry

Polyether polymer surfactants are often used as low-foaming detergents, emulsifiers, dispersants, defoaming agents, antistatic agents, wetting agents, printing and dyeing agents, etc.; polyvinyl alcohol and other polymer compounds are used as thickeners and protective colloids are widely used in the preparation of emulsion-type printing and dyeing auxiliaries; cellulose derivatives such as carboxymethyl cellulose are used in detergents as re-contamination inhibitors; lignin sulfonate, phenolic condensate sulfonate, etc. Used as a dispersant for insoluble dyes.

Application in paper industry

Because polymer surfactants play a very unique and important role in improving paper properties and improving paper machine efficiency, they have received more and more attention from papermaking workers in recent years. Studies have shown that maleic acid monoester is prepared from polyethylene glycol and maleic anhydride with different relative molecular weights, and then polymerized with acrylic acid to form maleic acid monoester and acrylic acid copolymer, which has a significant deinking effect.