Synthesis and Characterization of Submicrometer-Sized Polypyrrole−Polystyrene Composite Particles

Abstract

A conducting polymer, polypyrrole (PPy), has been deposited from aqueous media onto a submicrometer-sized poly(ethylene glycol)-stabilized polystyrene (PS) latex. Deposition experiments were carried out at two different initial pyrrole concentrations, and the latex concentration was systematically adjusted in order to control the final conducting polymer loading. Transmission electron microscopy studies showed that at a pyrrole concentration of 5.0 × 10-3 M the PPy had deposited onto the latex as discrete PPy nanoparticles of 20−30 nm diameter. These nanoparticles act as a bridging flocculant or binder, leading to heteroflocculation of the PS latex. Thus the expected “core−shell” morphology was not observed. Pressed pellet conductivity measurements indicated relatively low conductivities (∼10-2 S cm-1) for the composites at PPy loadings less than 20 wt %. This is in contrast to earlier studies (Lascelles, S. F.; Armes, S. P. J. Mater. Chem. 1997, 7, 1339) of micrometer-sized PPy-coated PS latexes which exhibited conductivities similar to PPy bulk powder (∼1 S cm-1) even at PPy loadings as low as 5 wt %. The relative colloid stabilities of the PPy−PS composites were assessed by disk centrifuge photosedimentometry (DCP) studies. For PPy loadings up to 16.6% or lower a reasonable degree of colloid stability was retained, but the PS latex particles were present as stable colloidal microaggregates, which is in good agreement with scanning electron microscopy studies. In contrast, DCP analysis confirmed that a PPy−PS composite prepared using a relatively low latex surface area and a pyrrole concentration of 5 × 10-4 M comprised mainly singlets, with a much smaller contribution from doublets, triplets, and higher aggregates.

All-Acrylic Film-Forming Colloidal Polymer/Silica Nanocomposite Particles Prepared by Aqueous Emulsion Polymerization

“…For example, incipient flocculation induced by either the physical adsorption of silica nanoparticles 9 or the deposition of an ultrathin overlayer of a conducting polymer is readily detected. [61][62][63] For example, Colard et al monitored the depletion of an ultrafine silica sol from the reaction solution during the in situ formation of polymer/silica colloidal nanocomposite particles. 53 However, one drawback associated with DCP is that a single value for particle density must be determined and input into the software to obtain meaningful size distributions.…”

Conductive Polymer Micro‐ and Nanocontainers

“…However, they claimed that these PANI overlayers still suffered from the shortcoming of nonuniform, inhomogeneous morphologies, in contrast to the relatively smooth morphologies obtained from the deposition of PPy onto the same sterically stabilized PS latexes [109][110][111]. It was also emphasized that nonuniform conducting-polymer deposits would be obtained if the latex was less hydrophobic [24,112,113]. Even though surface modification could generally optimize the deposition architecture of the PANI overlayer, it obviously complicates the synthetic procedure.…”

Multifunctional Polymeric Nanostructures for Therapy and Diagnosis

“…Recently, poly[vinylcaprolactum-co-(aceto acetoxtethyl methacrylate)] (VCL/ AAEM) microgels, functionalized with Ag nanoparticles have been studied for their physico-chemical properties [203]. In a study, hybrid fluorescent microgels were prepared via photoactivated synthesis of Ag nanoparticles in PNIPAAm microgels [210]. The PNIPAAm microgels, with a diameter of 200-600 nm, containing acrylic acid and 2-hydroxyethyl acrylate units for better integration of magnetic nanoparticles, have been synthesized recently [211].…”