Folder 3 contains the "chemistry" process in which "encapsulated polymers form in situ on the surface of payload droplet in a water environment". This type of process results in the formation of a film around the active payload. Many examples are described below.

Condensation. The coagulation process is initiated by dispersing or emulsifying a payload of the active substance in a gelatin solution (2%-10% gelatin) containing a polyanion such as gum Arabic. When the pH is raised to about 4 and the solution is cooled to about 10°C, the positively charged gelatin reacts with the negatively charged polyanion to form a "composite condensation layer" film on the payload surface. The membrane is further strengthened by crosslinking with aldehydes. As described elsewhere in this book, this composite condensation layer based on cationic modified hydroxy ethyl cellulose has been used to embed silicone oil in foam.

Variations of the above polymers have been used. Gum Arabic, for example, can be replaced by a number of synthetic and natural polyanions. It is difficult to find a material that can replace gelatin without compromising the quality of the product. However, experimenters have used chitosan and other natural gums with varying degrees of success. Overall, gelatin remains the best material for most coagulation processes.

Membranes obtained by condensation are known to break under shear forces applied during application (i.e. friction against the skin), and it is this break that releases the payload. This process is a valuable release mechanism, although its scope is limited because it does not offer the possibility of providing a continuous release feature.

The main benefit of the condensation technique is that it provides good protection against surfactants. This advantage is especially useful when the formulation requires the presence of sensitive payloads. In addition, coagulation technology leads to large and visible capsules that are attractive to consumers. The capsules must be strong enough to resist decomposition during incorporation into the prepared product prior to use. Therefore, care must be taken when using such materials to produce finished products. Alternatively, the strength of the outer wall can be adjusted to increase its resistance to breakdown through shear forces applied during machining.

Urea-formaldehyde film formed by in-situ polymerization on the surface of oil droplets. Although this approach is the primary packaging technology in many industrial market segments, its success in personal care applications to date has been limited.