A gel It is a state of matter between solid and liquid. It is a colloidal substance, that is, it is a mixture composed of two or more phases. Its size usually increases when it comes into contact with water (in the case of gels produced based on water).
exist different types of gels widely used in medicine, especially in dermatology. Gels are also used in aromatic products, foods, paints, and adhesives. For instance: bath gel, jelly, glass.
The process by which a gel is formed is called gelation.
Phases of the gels
The gels present Two phases; a continuous phase that is generally solid and a dispersed phase that is mostly liquid. Although this second phase is liquid, the gel has more the consistency of a solid than a liquid. There are also gels whose dispersed phase is a gas.
The most common gel example is jelly, where you can see the continuous phase (gelatin in granules or powder) and the dispersed phase (water).
The continuous phase gives the gel consistency and prevents it from flowing freely, while the dispersed phase prevents it from becoming a compact mass.
Characteristics of the gels
Certain gels have the characteristic to go from one colloidal state to another just by shaking. This characteristic is called “thixotropy.” An example of this are some paints, alkaline coatings and latex coatings. Other thixotropic gels are: tomato sauce, clays and yogurts.
The consistency of gels varies between solid viscous fluids and fluids with high stiffness, depending on the gel components.
It can be said that the gels show a certain degree of instability. However, as a general characteristic, the gels are moderately elastic.
Type of gels
Depending on the consistency of the gels, they can be classified into:
- Hydrogels. With a watery consistency, they use water as a dispersion medium. Most gels belong to this category.
- Organogels. They resemble hydrogels but use a solvent of organic origin. For example, the crystallization of wax in oil.
- Xerogeles. They are gels with a solid appearance since they do not have a solvent.
- Aerogels. They are gels whose dispersed phase is a gas. They are very low density solids.
Uses of the gels
Gels are widely used in medicine and chemistry. They are especially used in the facial and hair cosmetic industry.
In medicine, gels are used for treatments in the ear canal or in the nostrils, since both canals are difficult to access and the use of solid medicines would be difficult for their subsequent cleaning.
Examples of gels
- Clay
- Fiber optic cables (this petroleum-derived gel allows the fibers to remain flexible).
- Custard
- Bath gel
- Hair gel
- Reduction gel
- Common gelatin
- Jelly
- Mucous secretions (mucus or mucus). They are important because they maintain the humidity of the cavities of the human body.
- Yellow butter
- Mayonnaise
- Fruit jams (add pectins to thicken the consistency)
- Soft cheese
- Ketchup
- Glass
- Yogurt