Definition of complex coacervation: This involves creating a complex of gelatin and carboxymethylcellulose by playing on the opposite electric charge of the two natural polymers.
Microencapsulation By Coacervation
How microencapsulation works by Coacervation
1. Dispersion of the liquid to be encapsulated in water
In a stirred tank, the liquid to be encapsulated is dispersed in water. The size of the droplets obtained is regulated by the speed of the stirrer.
2. Introduction of a solution of gelatin and a solution of carboxymethylcellulose (CMC)
A solution of gelatin and a solution of carboxymethylcellulose (CMC), which still carries negative electrical charges, are then introduced into the stirred tank.
The medium is basic (pH> 7) and the gelatin carries negative electrical charges and nothing happens.
3. Introduction of acid to change the pH of the solution
Acid is introduced, the gelatin then carries positive charges and binds with the CMC. A compound of CMC and gelatin is formed and is then deposited around the drops of liquid dispersed in the water.
4. Stabilization of the polymer structure
The structure of the polymer is then stabilized This is done by chemical bonding between the gelatins and the CMC (by a polyaldehyde)
Gelatin-based microcapsules, transparent and flexible, adjustable in diameter from 1 μ to 2 mm, presentation in slurry or powder This technology allows the manufacture of sealed microcapsules or controlled release whose release rate can be adjusted according to applications.
This type of microcapsules is also sold in a food version.
Microencapsulation by Coacervation: our historical specialty
We have succeeded in developing microcapsules obtained by complex coacervation containing 35% of active ingredient for use in chemical carbonless, which could be deposited directly on the paper machine.
These microcapsules were sold at the time around the world, sometimes by complete tanker trucks.