Polymeric Nanoreactors for Hydrophilic Reagents Synthesized by Interfacial Polycondensation on Miniemulsion Droplets

Abstract

We describe a versatile method to obtain functional hollow nanoreactors with a hydrophilic liquid core. The synthesis of hollow polyurea, polythiourea, and polyurethane nanocapsules was performed by interfacial polycondensation or cross-linking reactions in inverse miniemulsion. The miniemulsions were built upon emulsification of a solution of amines or alcohols in a polar solvent with cyclohexane as the nonpolar continuous phase. The addition of suitable hydrophobic diisocyanate or diisothiocyanate monomers to the continuous phase allows the polycondensation or the cross-linking reactions to occur at the interface of the droplets. The wall thickness of the capsules can be directly tuned by the quantity of the reactants. The nature of the monomers and the continuous phase are the critical factors for the formation of the hollow capsules, which is explained by the interfacial properties of the system. The resulting polymer nanocapsules could be subsequently dispersed in water. The capsules were found to be spherical when formamide was used as the liquid core, whereas elongated capsules were obtained with water. Finally, we used these hollow nanoreactors as a model system for the preparation of silver nanoparticles by reducing silver nitrate solutions encapsulated by the polyurea shell. These syntheses are the first that allow the encapsulation of hydrophilic compounds in miniemulsion in a hollow structure.

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.…”

Microgel containers for self-healing polymeric materials: Morphology prediction and mechanism of formation

“…For the preparation of capsules especially on a micro-or nanoscale, an emulsion route is frequently used [18,23,[25][26][27][28][29][30][31][32][33]. With this approach, the droplets of dispersed phase of an 3 emulsion undergo an interfacial polymerization reaction such as polyaddition or polycondensation leading to the formation of polymeric network in the capsules shell or in the entire volume of micro-or nanoobjects yielding the compact particles.…”

Light-Sensitive Polymeric Nanoparticles Based on Photo-Cleavable Chromophores

“…Route (i) can be realized by either seeded precipitation/dispersion polymerization of a second monomer in the presence of seed particles representing the core [54][55] or nanoprecipitation of a preformed polymer around preformed nanoparticles or liquid droplets. 310,312 The orthogonal synthetic pathway (ii) can be realized by first forming nanocapsules through either polycondensation reactions 313 Dispersion and precipitation polymerizations are typically based on initiating the polymerization of a solution of a monomer (and crosslinker) in a near  solvent for the respective polymeric analogue. [38][39][40] While the polymerization proceeds, the monomer and formed oligomers are soluble until the growing chains reach a critical length.…”

“…313 Hereby, the incorporation of water soluble compounds can easily be achieved by dissolving the desired substance in the dispersed phase prior to emulsification. 317 Based on this concept, the work described in this chapter deals with the formation of core/shell nanoparticles consisting of a polyurea shell and a crosslinked polyacrylamide hydrogel core.…”