Membrane emulsification for the production of suspensions of uniform microcapsules with tunable mechanical properties

TL;DR

This paper presents a membrane emulsification method for producing uniform microcapsules with tunable mechanical properties, optimizing process parameters and shell assembly strategies for high throughput and consistent quality.

Contribution

It introduces a scalable microcapsule fabrication technique that controls size and elasticity despite different shell assembly kinetics.

Findings

Achieved size variation of 15% in microcapsules.

Developed strategies for uniform elastic properties.

Optimized process parameters for high throughput production.

Abstract

A way forward for high throughput fabrication of microcapsules with uniform size and mechanical properties was reported irrespective of the kinetic process of shell assembly. Microcapsules were produced using lab-scale emulsification equipment with a micro-engineered membrane in the size range 10-100 $\mu$m. The shell of the microcapsules was assembled at the water-oil interface by complexation of polyelectrolytes or cross-linking of proteins providing two different kinetic processes. Elasticity of microcapsules was characterized with an automated extensional flow chamber. Process parameters were optimized to obtain suspensions with size variations of 15%. Some strategies were developed to obtain uniform elastic properties according to the kinetics of shell assembly. If kinetics is limited by diffusion, membrane emulsification and shell assembly have to be split into two steps. If kinetics is limited by the quantity of reactants encapsulated in the droplet, variations of elastic properties result only from size variations.