Liquid-Core Capsules via Interfacial Polymerization:  A Free-Radical Analogy of the Nylon Rope Trick

Abstract

Liquid-core capsules have wide-ranging applications in the high-efficiency encapsulation and controlled release of drugs, dyes, enzymes, and other substrates. Their great utility has driven the rapid development of various preparation techniques. However, there remains no convenient technique for the preparation of submicrometer liquid-core capsules with shell thicknesses less than 100 nm. Here, we demonstrate a new interfacial free-radical polymerization approach for the straightforward preparation of liquid-core polymer capsules. Conceptually, this interfacial free-radical polymerization is analogous to the classical "nylon rope trick" wherein hydrophobic and hydrophilic monomers alternately copolymerize to constrain the polymerization at interfaces, but its free-radical mechanism allows precise control of initiation, which makes it possible to finely disperse the immiscible phases prior to polymerization.

Interfacial encapsulation of bio‐based benzoxazines in epoxy shells for temperature triggered healing

“…24 The structure of the resins and detailed calculations are presented in the Supporting Information. It can be seen that the solubility parameter of cycloaliphatic epoxy, benzoxazine, and TETA are in the same range, i.e., 9 ). 7,25 This difference in miscibility results in their existence as phase separated droplets under agitation.…”

“…8 In this article, we adopt an interfacial engineering approach to prepare epoxy microcapsules containing core of liquid benzoxazine. The potential of liquid-liquid interface toward the preparation of nanocrystals, thin films [9][10][11] , and microcapsules 12,13 has been well reported. We believe that this concept could very well be extended to prepare microcapsules with interesting morphologies.…”

Polymeric Nanoparticles Preparation Techniques and Applications for Drug Delivery System- A Brief Review.

“…[65] Nanometer-sized hollow polymer particles were synthesized by employing interfacial cross-linking reactions as polyaddition and polycondensation. [66][67][68] or radical polymerization. [69,70] Oil-containing nanocapsules were obtained by the polymerization of monomers at the oil/water interface of a very fine oil-inwater micro-emulsion.…”

From polymeric particles to multifunctional nanocapsules for biomedical applications using the miniemulsion process

“…63 Interfacial reactions are one of the well-established methods in the preparation of nanocapsules. The nanometersized capsules in direct emulsion were also synthesized using such interfacial crosslinking reactions as polyaddition and polycondensation, [64][65][66] radical, 67,68 or anionic polymerization. 2,69 The polyaddition between the chitosan stabilizer and two biocompatible costabilizers, i.e., Jeffamine D2000 or Gluadin, and a linking diepoxide in the presence of an inert oil was performed at the interface of direct miniemulsion droplets.…”