As an important dispersion system, colloids have some unique properties.
1. Optical properties of colloids have the Tyndall effect, when a beam of parallel light passes through the colloid, a bright "pathway" will be seen. This is due to the scattering of light by colloidal particles. 2. Electrical propertiesColloidal particles usually have an electric charge, so they can move directionally in the electric field to form electrophoresis phenomena. At the same time, the colloid can also be adsorbed to the electrode, resulting in electroadsorption. 3. Kinetic propertiesColloidal particles are larger, so their Brownian motion is slower and the diffusion speed is smaller. At the same time, due to the uneven charge distribution of colloidal particles, it will cause their forces to be unbalanced, resulting in electrophoretic motion. Fourth, the stability colloid has a certain stability and can maintain its dispersed state for a certain period of time. This is due to the strong interaction force between colloidal particles, which can resist the action of external forces such as gravity. 5. Aggregation and precipitation When colloidal particles are affected by certain factors, such as adding electrolytes and changing temperatures, the phenomenon of agglomeration and precipitation will occur, that is, colloidal particles gather together to form precipitation.
6. Dialysis. Because the colloidal particles are large and cannot pass through the semi-permeable membrane, while the ions and small molecules are small and can pass through the semi-permeable membrane, the colloids are purified by this method.
Therefore, colloids have unique optical, electrical, kinetic and stable properties, which make colloids have a wide range of applications in many fields.