Surfactants are versatile raw materials used in cosmetic formulation for a range of functions including cleansing, foaming, thickening and emulsifying. They are also used to improve product spreadability and provide skin/hair conditioning.
They can be natural or synthetic and are usually derived from petrochemicals. However, there are gia cong my pham alternatives from renewable raw materials that offer a compromise between price, efficiency and environmental impact.
Cosmetic Formulations with Surfactants
A cosmetic surfactant is a substance with a specific chemical structure that allows it to perform several essential functions in cosmetic formulas. These include emulsification, washing, foaming and solubilization.
The most commonly used surfactants are anionic. They offer excellent cleansing properties and are able to remove oil, fats and other debris from the skin’s surface. They are often combined with nonionic or amphoteric surfactants to reduce irritation. Examples of these include sodium lauryl sulfate and cetearyl alcohol.
When surfactants are present in solution they form micelles, a group of hydrophilic and lipophilic parts that resemble a cream filled donut. At low concentration, the surfactants randomly bounce around in water without forming structures, but at critical micelle concentration, they arrange themselves into spherical structures. The outer layers of the micelles are hydrophilic and the inside is lipophilic, allowing the surfactants to trap oils, dirt and sebum.
Functions of Surfactants in Cosmetics
Surfactants are essential ingredients in beauty products, providing multiple functions, such as cleansing, foaming, thickening, emulsifying and conditioning. They are also effective in improving the sensory experience of cosmetic products.
In the case of cleansing formulations, surfactants are designed to remove dirt and oil impurities from the skin surface by reducing surface tension. The negatively charged surfactant molecules bind to positively charged contaminants.
In emulsions, surfactants stabilize the mixture of water and oil-based ingredients to deliver smooth textures and enhanced efficacy. Moreover, they are capable of dispersing powders evenly and stably to maximize the whitening, concealing and sunscreen effects of products. Additionally, they are able to increase the solubility of some insoluble or hardly soluble ingredients by creating micelles of surfactant molecules that adsorb onto the surface of these materials.
Types of Surfactants for Cosmetics
Surfactants are one of the most important groups of raw materials used in cosmetic production. While they are often regarded as “bad” or dangerous ingredients, if selected correctly and used in appropriate concentrations, they perform a number of useful functions such as wetting, dispersing or emulsifying agents.
They are also excellent detergents and foaming agents. They can be synthetic or natural and are derived from starting materials such as petrochemicals through chemical reactions such as sulfonation and ethoxylation. Sodium lauryl or sodium laureth sulfates (SLS) and ammonium lauryl or ammonium laureth sulfate (ALS) are the most commonly used surfactants in cosmetic personal care products. They have hydrophilic and lipophilic ends which when added to water in sufficient concentrations, reorganise to form micelles – the hydrophilic heads are attracted towards water molecules, while the lipophilic tails are attracted to oils or fats.
Role of Surfactants in Emulsification
Surfactants are a key component of cleansing formulations, helping to lift oil from the skin and hair. They are also used as wetting agents, making it easier to apply cosmetic creams.
Depending on the nature of their molecules, surfactants are either nonionic, cationic or amphoteric. They have hydrophilic heads (like water loving flowers) and hydrophobic tails that bind to fats and oils. When surfactants are dissolved in water, they reorganize to form micelles – the hydrophilic head faces outward while the hydrophobic tails capture oil or dirt.
These properties make surfactants excellent detergents, wetting agents and emulsifiers. They are also known to disperse solid particles evenly and stably in cosmetic products to maximize their whitening, concealing and sunscreen effects. They are also used to create emulsions, such as oil in water or water in oil emulsions.
Impact of Surfactants on Formulation Quality
As emulsifiers, wetting agents, detergents, foaming agents, and dispersants surfactants play a major role in cosmetic formulations. They are important in the formulation of cleansing products that need to be gentle on skin and hair but still be effective at removing oily impurities from these tissues.
In very low concentrations surfactants simply bounce around randomly, but at a critical point, called the Critical Micelle Concentration (CMC), they self-assemble into thermodynamically stable structures called micelles. This allows the polar head group of the surfactant to interact with water molecules while the non-polar tail binds to non-polar oils and greases.
Unfortunately, the vast majority of chemical surfactants are derived from petrochemicals and are therefore a concern for healthy skin. There is an impetus to find new, sustainable surfactants that are derived from natural sources.
