What Components Can be Used as a Characteristic Index to Measure The Hydrophilicity of Surfactants

Nov 25, 2020

Surfactant Surfactant is a molecule formed by two completely different particles, one particle has a strong lipophilicity, and the other has a strong hydrophilicity. After being dissolved in water, surfactants can reduce the surface tension of water and improve the solubility of organic compounds.

 A wide range of surfactants (cationic?, anionic?, non-ionic and amphoteric) provide multiple functions for specific applications, including foaming effect, surface modification, cleaning, emulsion, rheology, environmental and health protection. Surfactants are used as performance additives in many industry formulations, such as personal and home care, and countless industrial applications: metal processing, industrial cleaning, oil extraction, pesticides, etc. Composition The molecular structure of surfactant is amphiphilic: one end is a hydrophilic group ?, the other end is a hydrophobic group ?. Principle Through the affinity of different parts of the molecule to the two phases, both phases are regarded as the components of the phase, and the molecules are arranged between the two phases, so that the surface of the two phases is equivalent to the inside of the molecule. Thereby reducing the surface tension. Since both phases regard it as a component of the original phase, it is equivalent to not forming an interface between the two phases and surfactant molecules, which is equivalent to partially eliminating the interface between the two phases in this way, and reducing The surface tension and surface free energy. Positive adsorption in adsorptive solution: increase wettability, emulsification, foaming; adsorption on solid surface: single-layer adsorption on non-polar solid surface, multi-layer adsorption can occur on polar solid surface. Traditionally believed that surface activity Agent is a class of substances that can significantly reduce the surface tension even at very low concentrations.

With the deepening of research on surfactants, it is generally believed that as long as the surface (interface) surface active agent properties or related and derived properties can be significantly changed at lower concentrations, they can be classified as surface Active agent category. No matter what kind of surfactant, its molecular structure consists of two parts. One end of the molecule is a non-extremely lipophilic hydrophobic group, sometimes called a lipophilic group; the other end of the molecule is a polar hydrophilic hydrophilic group, sometimes also called an oleophobic group or vividly called a hydrophilic head. Two types of molecular fragments or groups with diametrically opposite structures and properties are located at the two ends of the same molecule and are connected by chemical bonds to form an asymmetric and polar structure, thus giving this type of special molecule both hydrophilic and If it is lipophilic, it is not an overall hydrophilic or lipophilic character. This peculiar structure of surfactants is usually called an amphiphilic structure, and surfactant molecules are therefore often called amphiphilic molecules. Depending on the required properties and specific applications, surfactants are sometimes required to have different hydrophilic and lipophilic structures and relative densities. By changing the types of hydrophilic or lipophilic groups, their share and their position in the molecular structure, the desired hydrophilic-lipophilic balance can be achieved. After years of research and production, many types of surfactants have been derived, each of which contains many varieties, which makes it difficult to identify and select a specific variety. Therefore, it is necessary to make a scientific classification of thousands of surfactants in order to facilitate further research and production of new varieties, and to facilitate the screening and application of surfactants.
Hydrophilic English definition:hydrophilic property;hydrophilicity
Molecules with polar groups, Has a great affinity for water, can attract water molecules, or dissolve in water. The surface of the solid material formed by such molecules is easily wetted by water. This characteristic is the hydrophilicity of the substance.

Hydrophilicity refers to the physical property of molecules that can form short-term bonds through hydrogen bonds and water. Because it is thermodynamically suitable, this molecule can not only be dissolved in water, but also in other polar solutions.

A hydrophilic molecule, or the hydrophilic part of the molecule, refers to its ability to be polarized to the site where it can form hydrogen bonds and make it easier to dissolve in water for oil or other hydrophobic solutions . Hydrophilic and hydrophobic molecules can also be referred to as polar molecules and non-polar molecules, respectively. Soap has hydrophilic and hydrophobic ends, so that it can be dissolved in water or oil. Therefore, soap can remove the interface between water and oil. The material has an affinity for water.
Metal plates such as chromium, aluminum, zinc and their hydroxides and substances with capillary phenomena have good hydrophilic effects. Such as: hydrophilic size protein starch cellulose