Narrowly Size Distributed Zinc-Containing Poly(acrylamide) Latexes via Inverse Miniemulsion Polymerization

Abstract

Polyacrylamide nanoparticles containing zinc nitrate were prepared via inverse miniemulsion polymerization using ultrasound emulsification. The effects of sonication time, mode of sonication, nature and type of emulsifier, amount of zinc salt, solvent in the dispersed phase, nature of dispersed and continuous phases, and type of initiator on the nucleation mechanism, conversion, molecular mass of polymer, and size distribution of the latex particles were investigated. The results showed that an increase in sonication time up to 4 min and using an amphiphilic polymeric surfactant with a relatively short hydrophilic part improved both the monodispersity and the stability of the zinc-containing latexes. An increase in viscosity of the continuous phase (changed by means of different nonpolar solvents) and decrease in viscosity of the dispersed phase (varied by the amount of water) had also a positive effect on the monodispersity. At the same time, the average diameter of the particles in the range of 225 nm changed only marginally. The use of either highly hydrophilic (ammonium persulfate) or highly hydrophobic (2,2′-azobis(2-methylbutyronitrile)) initiators, and the transfer from miniemulsion polymerization to dispersion, precipitation, or a combination of several polymerization types by the modification of the dispersed and continuous medium spread the polydispersity of the latex particles and impaired the stability. Samples with small content of salt were used for unconventional nanolithography by subjecting a highly ordered layer of the nanoparticles to a plasma etching process. Highly ordered arrays of particles containing ZnO nanocrystals were observed.

Light-Sensitive Polymeric Nanoparticles Based on Photo-Cleavable Chromophores

“…This pathway results in hydrogel nanoparticles after transferring the polymerized latexes to water as continuous phase. Examples include the formation of polyacrylamide (PAAm) [73][74] and PHEMA [74][75] based microgels. Moreover, since the only main requirement for copolymerization of different monomers is their immiscibility with the continuous phase, this approach is highly tolerant to a broad variety of monomers and can be used to prepare e.g.…”

Monitoramento in Situ, Em Tempo Real Da Polimerizacao Em Miniemulsao De Acrilamida Utilizando a Espectroscopia Nir.

“…And the continuous phase, in which the droplets are dispersed, contains the nonionic surfactant, to retard coalescence (Landfester, 2000). Since monomer droplets/particles are the main polymerization locus and due to their high superficial area, the initiator may the either soluble in the dispersed phase Qi et al, 2007;Kobitskaya et al, 2010) or in the continuous phase (Qi et al, 2007;Kobitskaya et al, 2010;Romio et al, 2013) or in both phases as in the case of the redox initiation system used by Blagodatskikh et al (2006). NIR spectroscopy has the advantages of ease of handling, and rapid measurements, the ability to monitor simultaneously the different polymer properties (Reis et al, 2004 a, b;Chicoma et al, 2010), as well as the possibility of using a multiplexer system.…”

Acrylamide inverse miniemulsion polymerization: in situ, real-time monitoring using nir spectroscopy

“…The continuous phase, in which the droplets are dispersed, also contains a nonionic surfactant to retard coalescence (Landfester, 2000). Since monomer droplets/particles are the main polymerization locus and due to their high superficial area, the initiator may either be soluble in the dispersed phase Qi et al, 2007;Kobitskaya et al, 2010) or in the continuous phase (Qi et al, 2007;Kobitskaya et al, 2010;Romio et al, 2013) or in both phases, as in the case of the redox initiation system used by Blagodatskikh et al (2006).…”