Preparation of polymeric nanoparticles by novel electrospray nanoprecipitation

Abstract

Polymeric nanoparticles have important applications in drug delivery, biotechnology, diagnostics and energy harvesting. We report a new technique named electrospray nanoprecipitation, which combines electrospray with agitated solvent displacement. The process enables one-step formation of polymeric nanoparticles <100 nm in size that are near-monodisperse with a diameter range significantly lower than could be obtained using either electrospray or agitated solvent displacement technique alone. Both reduction of polymer solution concentration and the addition of poly(vinyl alcohol) emulsifier in the water-non-solvent medium further reduce the average particle diameter. The technique provides an effective and straightforward method to further reduce the size range of near-monodisperse nanoparticles achievable in a single step, which can be readily adapted for reducing the achievable size range of core-shell structures using popular one-step encapsulation techniques such as coaxial electrospray.

Development of magnetoelectric CoFe2O4 /poly(vinylidene fluoride) microspheres

“…It is to notice that those β-phase contents are compatible with the maximum piezoelectric response of the polymer, as it has been verified in 33 . In this way, the β-phase formation is mainly attributed to the low solvent evaporation temperature (≤ 60 o C), which mainly leads to the crystallization of the polymer in this phase 15,34 . Further, electrostatic interaction of the filler nanoparticles with the highly polar polymer chains certainly reinforce this effect, as it has been verified in samples prepared after melting, that are nucleated in the β-phase, whereas the polymer without fillers remain in the α-phase 15 .…”

“…In particular, polymer-based ME spheres composed by magnetostrictive nanoparticles within a piezoelectric polymer matrix, can open new applications areas and solve some drawbacks of the traditional polymer-based structures (nanocomposites, polymer as a binder and laminates) such as agglomeration, irregular distributions and the difficulty to shape in a miniaturized form 1,12 . Polymer-based micro and nanospheres undergo an increasing demand and applicability as biomaterials for cell culture, drug delivery systems, electro-optic and luminescent devices, heterogeneous catalysis and polymer powder impregnation of inorganic fibers in composites [13][14][15][16] .…”

“…For the formation of polymer microspheres several methods have been used such as gas atomization, microdroplet, dispersion polymerization, evaporation and precipitation, emulsion polymerization 13 , oil in water (O/W) or water in oil (W/O) emulsions, coacervation and spray drying, among others 19 . Unlike previous methods that require high-energy input devices like sonicators and/or high-cost devices such as high-pressure homogenisers, electrospray technique is a straightforward and versatile technique featuring advantages like ambient condition and single-step processing, high reproducibility, high yield and economical set-up 15,20,21 . In this work the development of novel CoFe 2 O 4 (CFO)/polyvinylidene fluoride (PVDF) multiferroic spheres is reported, with large potential applications in the biomedical, sensing, actuation, catalysis and energy fields [13][14][15] .…”

“…Unlike previous methods that require high-energy input devices like sonicators and/or high-cost devices such as high-pressure homogenisers, electrospray technique is a straightforward and versatile technique featuring advantages like ambient condition and single-step processing, high reproducibility, high yield and economical set-up 15,20,21 . In this work the development of novel CoFe 2 O 4 (CFO)/polyvinylidene fluoride (PVDF) multiferroic spheres is reported, with large potential applications in the biomedical, sensing, actuation, catalysis and energy fields [13][14][15] . PVDF, a piezoelectric polymer with five possible distinct crystalline phases named as α, β-phase, γ, δ and ɛ, was selected as the piezoelectric component due to its biocompatibility, high piezoelectric response, large chemical and radiation resistance, easy shaping and low cost 11,[22][23][24] .…”

Nano- and Micro-Particles by Nanoprecipitation: Possible Application in the Food and Agricultural Industries

“…Developing nanoparticles is explained by nucleation theory (Figure 1), which involves several steps: particle nucleation, growth, and aggregation (72). Nucleation occurs when the concentration of polymer reaches the critical limit of saturation, i.e., when the breaking of the interface between the polymer and solvent is carried out through the addition of the aqueous phase.…”