Encapsulation of Aliphatic Amines Using Microfluidics

Abstract

The encapsulation of amines by emulsification and interfacial polymerization is important for smart adhesives and self-healing materials but has been challenging because of the reactive nature of amines and their wide miscibility range. In this study, we propose a new method to encapsulate amines using double-emulsion templates made in a microfluidic device. The double emulsions contain an aqueous solution of the amine of interest in the innermost phase and a reactive mixture of acrylic monomers and initiator in the middle phase. Polymerization of the middle phase leads to acrylic microcapsules containing highly concentrated nonvolatile amine upon removal of water via evaporation. The presence of the amine inside the capsules is confirmed with NMR spectroscopy, and their reactivity is demonstrated by showing their effectiveness as cross-linkers of liquid epoxy resins.

Self-healing polymeric materials based on microencapsulated healing agents: From design to preparation

“…Hence, the authors investigated microfluidics techniques to encapsulate amines [184]. Microfluidics emulsion was first developed by Utada et al [185] Triethylenetetramine (TETA) was incorporated into acrylate microcapsules M a n u s c r i p t !…”

“…In recent years, some breakthroughs have been achieved in this area. Various amines have been successfully incorporated into microcapsules owing to the development of diverse microencapsulation techniques [124,125,153,180,184,204]. However, sometimes the healing ability of the amine capsules is not as good as expected due to the high viscosity of the core substance [124].…”

Recent advances in the production of controllable multiple emulsions using microfabricated devices

“…Polymer capsules with liquid cores have applications in the encapsulation of drugs, cells, pesticides, perfumes, liquid inks, paints, toners, solvents, and reactive liquid chemicals (Peyratout & Dähne, 2004;Vericella et al, 2015;Chen et al, 2014). The middle phase may also contain dissolved particles or amphiphilic molecules such as phospholipids or diblock copolymers, which can undergo self-assembly at two concentric oil/water interfaces upon solvent evaporation, which can lead to the formation of vesicles such as giant liposomes (Shum et al, 2008), polymersomes and colloidosomes (Table 2).…”

Quantifying thermoset polymers healing efficiency: A systematic review of mechanical testing

“…On the contrary, both capsules under analysis provided similar impact results. Figure 19: Pull-out and lap-shear tests evaluating healing adhesion [80][81].…”

“…Another group of studies focused on the adhesive bonding between polymer matrix and healing agent [80]. On that direction, modified tensile tests with the experimental configuration shown in Figure 19a were performed.…”