A Novel Route to Multiphase Polymer Systems Containing Nano‐Droplets: Radical Polymerization of Vinylic Monomers in Gelled Water‐in‐Oil Miniemulsions

Abstract

Summary: A new strategy for the synthesis of composite polymers with larger volume fraction of aqueous inclusions less than 1 µm in diameter is presented. A water‐in‐oil miniemulsion of aqueous droplets in a continuous, cross‐linkable monomer phase is prepared. The addition of an organo‐gelator allows the immobilization of the droplets in a solid gel, thus avoiding the usual demixing upon polymerization of the continuous phase. This pregelled system is then converted into a composite polymer by photoinitiated free radical polymerization. Such coatings may be used for an improved climate control of buildings or as a deposit for the controlled release of actives from polar nano‐droplets.

Emulsions with structured continuous phases

“…In many applications these materials appear in the form of spherical particles that are either used separately (e.g., gel capsules as drug carriers) or as components in liquid or gelatinous formulations. Recently, several studies have shown that insoluble gel particles can also be formed from mixtures of oppositely charged surfactants and polyelectrolytes [36][37][38][39].In this case surfactant aggregates act as physical crosslinks between the polyelectrolyte chains. These materials present an attractive alternative for the encapsulation of oils in surfactant-based products.…”

“…Gellation also helps the use of emulsions as templates for the preparation of porous materials [36][37][38]. Gelled emulsions are often produced using a two-step process in which first oil is dispersed in an aqueous polymer solution that is then gelled to trap the oil droplets in the gel matrix.…”

Nano- and microparticles of gelled oil combining aminoacid-based low molecular weight organogelators and nonionic amphiphilic polysaccharides

“…Schematically, two types of colloidal dispersions have been reported involving organogels, according to the nature of the gelled phase. On the one hand, water-in-oil emulsions have been prepared in which the oil phase was gelled [8][9][10][11][12][13][14][15]. Gelling continuous oil phase prevented water droplets motion as well as coalescence and thus improved the colloidal stability of the dispersions.…”

Alginate microgel particles: stability, rheology and application as bioactive carrier

“…This increase in viscosity will limit the free movement of emulsion droplets thereby preventing droplet collision. Emulsion instability such as coalescence, creaming, flocculation, and Ostwald ripening, which are partly initiated by droplet collisions, will be limited (Holtze, Landfester, & Antonietti, 2005;McClements, 2005). In comparing conventional porcine myofibrillar protein (MP) stabilized emulsion with MP emulsion gel (MTGase and alginate), Hong et al (2012) found that the emulsion gel system showed high creaming stability compared to the conventional emulsion system.…”