Polymer-silica Nanocomposites Research Articles

Surface characterization of vinyl polymer–silica colloidal nanocomposites using X-ray photoelectron spectroscopy

We report the use of X-ray photoelectron spectroscopy (XPS) to characterize the surface compositions of colloidal nanocomposite particles. Each nanocomposite was synthesized by (co)polymerizing 4-vinylpyridine in the presence of an ultrafine silica sol. Thus, nitrogen and silicon were utilized as unique elemental markers for the (co)polymer and silica components, respectively, and the silicon/nitrogen atomic ratios determined by XPS were used to assess the surface compositions of the particles. For all the homopoly(4-vinylpyridine)–silica nanocomposites examined, the XPS surface compositions are comparable to the bulk compositions determined by thermogravimetric analyses and elemental microanalyses. This is consistent with the ‘currant bun’ particle morphologies observed by transmission electron microscopy (TEM) and indicates that the silica particles are uniformly distributed throughout the nanocomposite particles. In contrast, the particle surface of a poly(styrene-co-4-vinylpyridine)–silica nanocomposite is distinctly silica-rich, as judged by XPS; this suggests a core–shell morphology, with the silica component forming the shell and the hydrophobic copolymer forming the core. Both the ‘currant bun’ and core–shell particle morphologies are supported by TEM studies of nanocomposite particles sectioned using cryo-ultramicrotomy. A poly(methyl methacrylate-co-4-vinylpyridine)–silica nanocomposite shows an XPS surface composition which is intermediate between those found for the ‘currant bun’ particles and the core–shell particles. In view of its relatively high silica content, a ‘raspberry’ particle morphology, similar to that previously reported for conducting polymer–silica nanocomposites, is suggested. Finally, it is shown that, in the case of the poly(methyl methacrylate-co-4-vinylpyridine)–silica nanocomposite, it is possible to use the carbonyl carbon signal of the methyl methacrylate residues as an unambiguous marker for the copolymer component; the surface composition obtained from this alternative analysis is consistent with that calculated using the nitrogen XPS signal. This approach may be particularly useful for assessing the surface compositions of nanocomposites containing a relatively low (or zero) proportion of 4-vinylpyridine co-monomer.

Synthesis, structure, and morphology of polymer-silica hybrid nanocomposites based on hydroxyethyl methacrylate

Two types of polymer–silica nanocomposites have been prepared by undergoing free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) either in the presence of HEMA-functionalized SiO2 nanoparticles (Type 1) or during the simultaneous in situ growing of the silica phase through the acid-catalyzed sol–gel polymerization of tetraethoxysilane (TEOS) (Type 2). Relationships between synthesis conditions, chemical structure, and resulting morphology have been studied. Type 1 systems exhibit a classical particle-matrix morphology, but where particles tend to form aggregates. Type 2 systems possess a finer morphology characterized by a very open mass-fractal silicate structure, which is believed to be bicontinuous with the organic phase at a molecular level. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 3172–3187, 1999

Synthesis of Novel Polymer-Silica Colloidal Nanocomposites via Free-Radical Polymerization of Vinyl Monomers

Polymer nanocomposites can exhibit unusual properties, and potential applications include catalyst supports and abrasion-resistant coatings. The copolymerization of 4-vinylpyridine in the presence of ultrafine silica sol is reported here to give rise to stable colloidal dispersions of polymer–silica nanocomposites which display a distinctive “currant bun” morphology (see Figure) in contrast to previously reported “raspberry” morphologies.

Synthesis of Novel Polymer–Silica Colloidal Nanocomposites via Free-Radical Polymerization of Vinyl Monomers

Polymer nanocomposites can exhibit unusual properties, and potential applications include catalyst supports and abrasion-resistant coatings. The copolymerization of 4-vinylpyridine in the presence of ultrafine silica sol is reported here to give rise to stable colloidal dispersions of polymer–silica nanocomposites which display a distinctive “currant bun” morphology (see Figure) in contrast to previously reported “raspberry” morphologies.

Synthesis-Morphology-Mechanical Properties Relationships Of Polymer-Silica Nanocomposite Hybrid Materials

ABSTRACTTwo types of polymer-silica nanocomposites have been prepared by undergoing free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) either in the presence of HEMA-functionalized SiO2 nanoparticles (Type 1) or during the simultaneous in situ growing of the silica phase through the acid-catalyzed sol-gel polymerization of tetraethoxysilane (TEOS) (Type 2). Relationships between synthesis, morphology and mechanical properties are discussed mainly on the basis of solid state 29Si nuclear magnetic resonance spectroscopy (NMR), transmission electron microscopy (TEM), small angle X-ray scattering (SAXS), and dynamic mechanical analysis (DMA).

Surface Characterization of Conducting Polymer-Silica Nanocomposites by X-ray Photoelectron Spectroscopy

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface Characterization of Conducting Polymer-Silica Nanocomposites by X-ray Photoelectron SpectroscopyShuichi Maeda, Michael Gill, Steven P. Armes, and Ian W. FletcherCite this: Langmuir 1995, 11, 6, 1899–1904Publication Date (Print):June 1, 1995Publication History Published online1 May 2002Published inissue 1 June 1995https://doi.org/10.1021/la00006a014RIGHTS & PERMISSIONSArticle Views544Altmetric-Citations91LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts