A colloidal suspension is a mixture of two materials where one is microscopically dispersed in the other, but not chemically bonded. Examples include milk, paint, smoke, and human blood. Colloidal particles can scatter light, creating a reflective quality. The balance between repulsive charges and attractive forces keeps the particles suspended. Hydrophobic detergent molecules can maintain this balance.
A colloidal suspension is a mixture usually of two materials in which one is microscopically dispersed in the other, but not chemically bonded to it. Liquids, solids, and gases can all be part of a colloidal suspension with the exception that a gas cannot be suspended colloidal in another gas. The particles that serve as a colloid in a suspension are typically larger in size than those found in solutions and range from 1 to 1,000 nanometers or billionths of a meter in diameter. They tend to spread evenly throughout the suspension if it has been stirred or recently stirred, but sink to the bottom of the solution due to gravity if it is allowed to sit undisturbed for an extended period of time.
Good examples of colloidal suspensions include milk, paint and smoke. The milk of cows, goats and other animals is a suspension of fat globules in liquid water, as an example of a liquid colloid suspended in a liquid. Paint is an example of a solid colloid suspended in a liquid in which paint pigments, often composed of heavy metal powders such as chromium oxide or zinc, are suspended in solvent bases of oil, water or hydrocarbons. Smoke is an example of a solid colloid suspended in a gas, where the smoke is composed of fine particles of ash as a combustible residue dispersed in the air. Human blood is also considered a colloidal suspension, with biological materials such as solid proteins suspended in liquid blood serum or plasma.
A unique property of many colloids is that they can have an opaque or translucent appearance. This is because the suspended particles are often quite large individually or as collections of molecules that act to partially scatter the light as it passes through the colloidal suspension. Blue light tends to be scattered much more effectively than longer wavelengths of light, such as red light, so colloidal suspensions often have a blue-tinged appearance, like mist in the air. This characteristic of a colloidal suspension has been used to create special types of paints and varnishes which have a reflective quality which imparts a glow to the coated surface. The suspension of the particles and the glow can be maintained to some extent, even after drying.
The properties of a colloidal suspension exist in a rather delicate balance. The colloidal particles will remain in suspension and avoid clumping together if the repulsive charges they carry balance against the natural attractive Van der Waals forces in the suspension. Artificial means of maintaining this balance have been developed to create colloidal suspensions. An example of this is a hydrophobic detergent molecule which can act as a colloid in water with a natural ability to avoid bonding with water molecules, but possesses an attractive charge towards dirt and oil particles even suspended in the water. ‘waterfall.
Protect your devices with Threat Protection by NordVPN
