Micelles意思

Micelles are tiny spherical structures formed by amphiphilic molecules (molecules that have both hydrophilic and hydrophobic parts) in a solution. When such molecules are dissolved in a solvent, they arrange themselves in a way that the hydrophobic parts are shielded from the solvent (usually water) and the hydrophilic parts interact with the solvent.

In the case of micelles, the hydrophobic parts face the center of the sphere, away from the solvent, while the hydrophilic parts extend towards the solvent, forming the outer surface of the micelle. This arrangement minimizes the overall energy of the system by reducing the contact between the hydrophobic parts and the solvent.

Micelles are commonly found in solutions of soap or detergents, where the molecules are surfactants—surface-active agents that lower the surface tension of a liquid and can emulsify or dissolve other substances. When the concentration of surfactants in water is below a certain threshold, called the critical micelle concentration (CMC), the molecules are simply dissolved in the water. However, when the concentration exceeds the CMC, micelles start to form.

The size of micelles can vary depending on the type of amphiphilic molecule and the solution conditions. They can range from a few nanometers to tens of nanometers in diameter. Micelles play important roles in various phenomena, including cleaning, foaming, and the solubilization of oils and other hydrophobic substances in water. They are also found in biological systems, such as in the cell membranes of organisms, where they are known as lipid bilayers.