What do hydroxyl groups in an emulsifier do in relation to water?

Hydroxyl groups are functional groups characterized by the presence of a hydrogen atom connected to an oxygen atom (-OH). In the context of an emulsifier, these hydroxyl groups exhibit hydrophilic (water-attracting) properties due to the ability of the oxygen atom to form hydrogen bonds with water molecules. This makes hydroxyl groups soluble in water and aids in the emulsification process.

When an emulsifier is introduced to a mixture of oil and water, the hydrophilic parts, such as the hydroxyl groups, interact with the water phase. They help to stabilize the emulsion by allowing oil droplets to disperse in water, as the hydrophilic ends orient towards the water while the hydrophobic parts interact with the oil. This action prevents the oil and water from separating, leading to a stable emulsion. As a result, the function of the hydroxyl groups is crucial in maintaining the stability and functionality of emulsifiers in various formulations, especially in food and cosmetic industries.