Polymerization in Microemulsions with Polymerizable Cosurfactants:  A Route to Highly Functionalized Nanoparticles

Abstract

The polymerization of styrene-in-water microemulsions prepared using polymerizable cosurfactants, such as hydroxyalkyl acrylates or methacrylates, gives rise to stable suspensions of well-defined highly functionalized nanoparticles in the 15−25 nm diameter range. Among the various associations of ionic surfactants with hydroxyalkyl (meth)acrylate cosurfactants tested, the surfactant/cosurfactant system (sodium dodecyl sulfate/2-hydroxypropyl methacrylate) is found to be the most effective and allows the preparation of oil in water microemulsions of styrene (up to 7 wt %) or mixture of monomers. Polymerization with 100% conversion is achieved at room temperature using either an oil-soluble photoinitiator (DMPA) or water-soluble redox systems (hydrogen peroxide/ascorbic acid or ammonium persulfate/diamine). GC monitoring of conversion for both monomers clearly demonstrates that the mechanism of copolymerization depends on the location of the reactive species (monomer, polymerizable cosurfactant, and radical initiator). The resulting polymers contain up to 40% of hydroxylated units.

Reactive surfactants in heterophase polymerization

“…Microemulsion polymerization yields stable latexes in the nanosize range (a 50 nm) that find applications in drug delivery, microencapsulation and biomedical diagnosis [156][157][158]. Most of these applications require highly functionalized particles, which have been prepared by using a second monomer bearing the desired functionality [159].…”

“…Most of these applications require highly functionalized particles, which have been prepared by using a second monomer bearing the desired functionality [159]. Larpent et al [160,161] reported on the use of polymerizable cosurfactants to produce highly functionalized nanoparticles. It should be pointed out that although these cosurfactants help lowering the interfacial tension of the system, they are not true surfactants in the sense that they cannot emulsify two nonmiscible phases.…”

Covalent Hybrid Materials Based on Nanolatex Particles and Dawson Polyoxometalates

“…[29] The aqueous suspension of chlorobenzyl-functionalized crosslinked polymer nanoparticles, the nanolatex NL-CH 2 Cl, was obtained by the copolymerization of styrene, vinyl benzyl chloride, and hydroxypropyl methacrylate (cosurfactant) in an oil-in-water microemulsion stabilized with an anionic surfactant (sodium dodecyl sulfate, SDS). [31] We chose an anionic surfactant stabilizer rather than a cationic one in order to i) limit the competitive hydrolysis of the chlorobenzyl surface end-groups, [9] and ii) avoid any electrostatic attraction and further self-assembly with the heteropolyanion or the final negatively charged hybrid nanoparticles. The grafting is readily performed in water at room temperature by adding POM-SH to the as-prepared nanolatex NL-CH 2 Cl.…”

“…Reactive Nanoparticles, NL-CH 2 Cl: The starting aqueous suspension of chlorobenzyl-functionalized nanoparticles, i.e., the nanolatex NL-CH 2 Cl, was prepared using a previously described procedure [31]. A mixture of monomers (styrene, chloromethylstyrene, vinyl benzyl chloride (VBCl), and divinyl benzene (DVB) as crosslinking agent) in an oil-in-water microemulsion that was stabilized by a mixture of a polymerizable cosurfactant (hydroxypropyl methacrylate, HPMA) and an anionic surfactant (SDS) were polymerized.…”

Copolumers obtained by grafting of vinyl monomers on starch - influence of amines on synthesis and degradation processes in environment

“…Sa povećanjem koncentracije TMEDA zapaţa se isti trend za vrednosti prinosa i efikasnosti kalemljenja kao i kod KPS-a. Sistem APS-tetrametildiaminometan se upotrebljen je za polimerizaciju stirena u mikroemulziji [272]. Stepen konverzije monomera od 100 % dostignut je za 2 h na temperaturi od 25 0 C u mikroemulziji SDS/1-pentanol.…”