Perfume Microencapsulation in Cosmetic Products

Since the 1990s, microencapsulation technologies have become essential in all areas of industry. The popularity of microencapsulation reflects its functional and sensory benefits. At the same time, the impact of fragrance has become one of the main driving forces behind the purchase and re-purchase of everyday consumer products, and demand for fragrances that perform better, last longer or provide the user with new olfactory experiences has exploded.

The promises of encapsulation applied to fragrances are manifold. A first advantage lies in the ability to isolate sensitive fragrance molecules in a microcapsule from chemical attack, such as oxidation or hydrolysis, or to prevent the release of these substances too early into the surrounding environment, for example by diffusion or evaporation. A second advantage is that this release can be controlled according to a predefined schedule, by adjusting the permeability of the capsule or by external stimuli. The microcapsule can also be a vehicle for transporting the fragrance to a substrate where release will take place. Lastly, this vehicle can be functionalized to increase its ability to recognize this substrate and bind to it, which makes particular sense when talking about products subject to rinsing, such as detergents, shampoos or shower gels.

This makes it possible to incorporate selected fragrances or perfumery ingredients into aggressive environments, keep them in this state for varying periods of time and, when and where required, release them to perform their function. In short, encapsulation enables the protection, vectorization and controlled release of fragrance.

The release can be slow and long-lasting, prolonging the impact of the fragrance beyond what is possible in the absence of microencapsulation, or on the contrary explosive, for example by breaking the capsule, offering the consumer a unique olfactory experience. Alternatively, the combination of these advantages can also enable a reduction in the level of fragrance in a product while maintaining its performance. This latter option is particularly interesting when incorporating fragrance into the product is difficult.

However, fragrance encapsulation remains a challenge. Fragrance molecules are small and difficult to confine in a capsule or particle, due to their tendency to diffuse through a large number of encapsulation materials. The drivers of this diffusion are volatility and partitioning between the inner and outer phases. Diffusion losses limit the stability of these systems in products that are often rich in surfactants and have a high extraction power. Finding the right compromise between retention during storage and release of the fragrance when and where required is often a challenge,...