Surface−Atom Transfer Radical Polymerization from Silica Nanoparticles with Controlled Colloidal Stability

Harrak, Abdeslam El; Carrot, Géraldine; Oberdisse, Julian; Eychenne-Baron, Christophe; Boué, François

doi:10.1021/ma035959w

Cited by 112 publications

(101 citation statements)

References 27 publications

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“…The specific surface area was evaluated by BET and was found to have an average value of 193 ± 1 m 2 /g. Both the average size and specific surface area agree with the values reported in literature [61].…”

Section: Methodssupporting

confidence: 90%

Interfacial characterization of epoxy/silica nanocomposites measured by fluorescence

Antonelli

Serrano

Baselga

et al. 2015

European Polymer Journal

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Fluorescence labeling was used as a tool for the interfacial characterization of nanocom-posites. The solvatochromic probe dansyl chloride was employed as interfacial reporter in epoxy/silica nanocomposites. Molecular spacers (organosiloxanes and polyetheramines) of different lengths were used to vary the location of the chromophore at the interface. The steady state and time resolved fluorescent responses reflect a rigid polar interface. Fluores-cence changes during heating at a constant rate were analyzed for determining the local glass transition (T g ) at the interface region. The fluorescence results were then compared to the T g obtained from differential scanning calorimetry and the results showed the existence of a gradient interface of a few nanometers thick having different properties than the bulk matrix. The thickness of this interface is small but its altered dynamics due to strong interactions with the nanofiller spreads its influence throughout the whole matrix.

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Section: Methodssupporting

confidence: 90%

Interfacial characterization of epoxy/silica nanocomposites measured by fluorescence

Antonelli

Serrano

Baselga

et al. 2015

European Polymer Journal

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“…Traditionally, coupling agents or surfactants have been widely used to stabilize the NPs [15,16]. More recently, ''grafting to'' and ''grafting from'' techniques have become popular methods to modify NPs with polymer brushes [17][18][19][20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Dispersion of polymer-grafted magnetic nanoparticles in homopolymers and block copolymers

Ohno

Ladmiral

et al. 2008

Polymer

155

145

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The dispersion of magnetic nanoparticles (NPs) in homopolymer poly(methyl methacrylate) (PMMA) and block copolymer poly(styrene-b-methyl methacrylate) (PS-b-PMMA) films is investigated by TEM and AFM. The magnetite (Fe 3 O 4 ) NPs are grafted with PMMA brushes with molecular weights from M = 2.7 to 35.7 kg/mol. Whereas a uniform dispersion of NPs with the longest brush is obtained in a PMMA matrix (P = 37 and 77 kg/mol), NPs with shorter brushes are found to aggregate. This behavior is attributed to wet and dry brush theory, respectively. Upon mixing NPs with the shortest brush in PS-b-PMMA, as-cast and annealed films show a uniform dispersion at 1 wt%. However, at 10 wt%, PS-b-PMMA remains disordered upon annealing and the NPs aggregate into 22 nm domains, which is greater than the domain size of the PMMA lamellae, 18 nm. For the longest brush length, the NPs aggregate into domains that are much larger than the lamellae and are encapsulated by PS-b-PMMA which form an onion-ring morphology. Using a multicomponent Flory-Huggins theory, the concentrations at which the NPs are expected to phase separate in solution are calculated and found to be in good agreement with experimental observations of aggregation. The dispersion of magnetic nanoparticles (NPs) in homopolymer poly(methyl methacrylate) (PMMA) and block copolymer poly(styrene-b-methyl methacrylate) (PS-b-PMMA) films is investigated by TEM and AFM. The magnetite (Fe 3 O 4 ) NPs are grafted with PMMA brushes with molecular weights from M ¼ 2.7 to 35.7 kg/mol. Whereas a uniform dispersion of NPs with the longest brush is obtained in a PMMA matrix (P ¼ 37 and 77 kg/mol), NPs with shorter brushes are found to aggregate. This behavior is attributed to wet and dry brush theory, respectively. Upon mixing NPs with the shortest brush in PS-b-PMMA, as-cast and annealed films show a uniform dispersion at 1 wt%. However, at 10 wt%, PS-b-PMMA remains disordered upon annealing and the NPs aggregate into 22 nm domains, which is greater than the domain size of the PMMA lamellae, 18 nm. For the longest brush length, the NPs aggregate into domains that are much larger than the lamellae and are encapsulated by PS-b-PMMA which form an onion-ring morphology. Using a multi-component Flory-Huggins theory, the concentrations at which the NPs are expected to phase separate in solution are calculated and found to be in good agreement with experimental observations of aggregation.

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“…Therefore, in the Ag/Pt nanoparticles, charge transfer from silver to oxygen was reduced, thus increasing the shielding effect of the valence electrons in Ag ions, which in turn decreased the binding energy of core electrons in Ag ion. This complex modification of silver binding state was associated with the variation in the number of broken bonds per silver ion due to quantum size effect, which led to the formation of oxygen vacancies in the host [37].…”

Section: Xps Resultsmentioning

confidence: 99%

Polyol mediated hexadecylamine capped silver allied nanobimetallic particles and their fluxional properties

Adekoya

Dare

Mesubi

et al. 2015

Journal of Physics and Chemistry of Solids

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe syntheses of hexadecylamine seed mediated Ag/M(M = Co, Ni, Pd and Pt) allied nanobimetallic particles were successfully carried out by the successive reduction of ligand capped metal ions with polyols, resulting in concomitant precipitation of some high index faceted hybrid Ag/M bimetal nanoparticles. The optical measurements revealed the existence of surface plasmon band and peak broadening that causes diffusion processes of the metal sols to decrease making it possible to monitor the changes spectrophotometrically. The bimetallic nanoparticles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and electron microscopy techniques which confirm the formation of alloyed clusters.

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Surface−Atom Transfer Radical Polymerization from Silica Nanoparticles with Controlled Colloidal Stability

Cited by 112 publications

References 27 publications

Interfacial characterization of epoxy/silica nanocomposites measured by fluorescence

Interfacial characterization of epoxy/silica nanocomposites measured by fluorescence

Dispersion of polymer-grafted magnetic nanoparticles in homopolymers and block copolymers

Polyol mediated hexadecylamine capped silver allied nanobimetallic particles and their fluxional properties

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