New ultrasonic technic for on-line encapsulation monitoring

This presented work shows the ability for this method to monitor the encapsulation process for fragrance delivery. The encapsulation is based on the coacervation principle which consists in the chemical reaction between two water soluble polyelectrolytic polymers with opposite charges. An experimental protocol is performed with precise conditions of temperature and acidity to form, during the process, elastic micro-shells encapsulating the fragrance. Thus, in this paper, the new ultrasonic technic is presented. It is based on the resonance of an AT cut quartz sensor. When the sensor is loaded, using the shear wave propagation in the complex fluid, the mechanical impedance of the material is extracted from the modification of the resonance parameters [1]. A complete on-line monitoring can then be carried out during the encapsulation process. The obtained results allow focusing the different steps of the encapsulation. This new system is inexpensive and easily adaptable to industrial conditions. It is robust in aggressive conditions. The evolution is to make this system remotely controlled.