Monodisperse core-shell alginate (micro)-capsules with oil core generated from droplets millifluidic
Résumé
Droplets millifluidic devices are efficient tools to produce monodisperse emulsions that can be used as template for the production of core-shell capsules. This work aims to develop an original alginate inverse gelation method to produce (micro)-capsules with a narrow size distribution using droplets millifluidic. Water-in-oil (W/O) emulsion dispersed phase containing Ca 2þ ions was directly injected into a continuous alginate phase to generate a secondary W/O/W emulsion. Due to the cross-linking of alginate molecules by Ca 2þ ions release, core-shell (micro)-capsules were formed with a very high oil loading. This study demonstrated for the first time the production of (micro)-capsules based on the inverse gelation mechanism using a simple millifluidic device. Monodisperse core-shell capsules with sizes ranging from 140 mm to 1.4 mm were produced by tuning flow rates of the continuous and dispersed phases and by varying internal diameter of the capillary tubing. The use of millifluidic devices paves the way to an integrative formulation of core-shell materials with very large characteristic sizes and new complex architectures. This should lead to the rapid emergence of new products in cosmetics or food where the texture and visual aspect play a key role for sale.
