Surface‐Initiated Controlled Radical Polymerization from Silica Nanoparticles with High Initiator Density

Chakkalakal, Golda Louis; Alexandre, Michaël; Abetz, Clarissa; Boschetti‐de‐Fierro, Adriana; Abetz, Volker

doi:10.1002/macp.201100625

Cited by 23 publications

(19 citation statements)

References 30 publications

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“…Although surface curvature may affect graft density in an SI-ATRP reaction, 27 it had small contribution to the final graft density here. In entries 1 and 2, each polymer chain occupied an average area of 33 and 7 nm 2 , respectively, far larger than the cross-sectional area of a PMMA brush.…”

Section: Acs Macro Lettersmentioning

confidence: 94%

Enhancing Initiation Efficiency in Metal-Free Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP)

et al. 2016

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Well-defined polymer-inorganic hybrid materials were prepared via metal-free surface-initiated atom transfer radical polymerization (SI-ATRP) with 10-phenylphenothiazine (PhPTZ) as the photocatalyst and 2-bromo-2-phenylacetate initiator tethered to silica surfaces. Initiation efficiency and, hence, graft density were significantly enhanced by this very reactive initiator. The polymerization kinetics, effect of initiator structures, particle sizes, and catalyst concentrations were investigated. Well-defined hybrid particles were prepared at a low catalyst concentration (0.02 mol % or 0.1 mol % to monomer). Poly(methyl methacrylate) (PMMA) with number-average molecular weight of 3.65 × 10 4 , dispersity of 1.43, and graft density of 0.60 chain/ nm 2 was grafted from the surface of silica nanoparticles. The hybrid materials were characterized with size exclusion chromatography (SEC), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and transmission electron microscopy (TEM). I n the past two decades, atom transfer radical polymerization (ATRP) has emerged as one of most versatile and robust methods for preparation of polymers with controlled molecular weight (MW), molecular weight distribution (MWD), architectures, and functionality. 1 However, the use of ATRP metal catalysts, such as copper complexes, results in the presence of an inevitable metal residue in final product. The presence of metal impurities in the products may limit the use of these polymers in electronic and biomedical applications. Extensive research has been carried out on catalyst removal from ATRP products. 2 Indeed, various low-ppm catalyst ATRP methods were developed to avoid time-consuming and costly catalyst removal, including activator regenerated by electron transfer (ARGET) ATRP, 3 use of Cu(0) as supplementary activator and reducing agent (SARA) ATRP, 4 initiators for continuous activator regeneration (ICAR) ATRP, 5 electrochemical ATRP (eATRP), 6 or photoinduced ATRP (photo-ATRP). 7 In addition to copper catalysts, other metal complexes, such as ruthenium, 8 iridium, 9 and iron 10 catalysts were used for ATRP. Although some recent developments utilizing less toxic iron-based catalyst in ATRP improved the biocompatibility of the products, they still have some limitations. 11 Recently reported, a photoinduced metal-free ATRP using an organic catalyst eliminated residual metal in the product. 12 A wide range of monomers, including methacrylates and acrylonitrile were successfully polymerized via metal-free ATRP. A photoexcited 10-phenylphenothiazine (PhPTZ) acted as the activator and the resulting radical cation served as the deactivator, resembling Cu(I) and Cu(II) species in conventional ATRP (Scheme 1).Surface-initiated ATRP (SI-ATRP) is an important synthetic technique for preparation of polymer−inorganic hybrid materials. 13 The development of metal-free techniques eliminates metal impurities from various functional materials prepared via SI-ATRP, including porous carbon for catalysis 14 and porous titania for dye ...

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Section: Acs Macro Lettersmentioning

confidence: 94%

Enhancing Initiation Efficiency in Metal-Free Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP)

et al. 2016

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“…Such knowledge would not only be highly interesting on a fundamental level but also for many practical applications as well. For example, it might help explaining the very unusual property profiles of interphase‐dominated polymeric systems such as nanocomposites or thin films and layers 6–17…”

Section: Introductionmentioning

confidence: 99%

Polystyrene Brushes on Fully Deuterated Organic Nanoparticles by Surface‐Initiated Nitroxide‐Mediated Radical Polymerization

Mazurowski

Sondergeld

Elbert

et al. 2013

Macro Chemistry & Physics

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The synthesis of polystyrene (PS) brushes on fully deuterated PS nanoparticles by surface-initiated nitroxide-mediated radical polymerization (SI-NMRP) is reported. Due to the high demand of deuterated monomers, an effi cient deuteration procedure of suitable and readily available precursors is developed. SI-NMRP of styrene is improved regarding reaction control, grafting density, and conversion. Insights into the scaling behavior and conformational features of surface-attached PS chains on deuterated particles are investigated by using dynamic light scattering measurements, proving that polymer brushes are formed. The particles with surface-attached initiator are shown to be uniform spherical core-shell particles by small-angle neutron scattering measurements.

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“…95,137,147,178,179 Additionally, free polymers produced by the sacrificial free initiator form an entangled network structure which prevents nanoparticle diffusion, diminishes interparticle coupling, and avoids gelation or aggregation. 95,137,147,178,179 Up to now, utilizing surface-initiated ATRP, various synthetic polymers such as PSt, 41,138,148,161,162 PMMA, 139,147,148,162,177 poly(n-butyl acrylate) (PnButA), 94 142 as well as polyelectrolytes 142,151,[163][164][165] have been grafted from silica nanoparticles (Table 1). Due to the living character of CRP techniques, it is possible to continue the polymerization with a second monomer after consumption of the first monomer, which leads to block copolymer-grafted silica nanoparticles.…”

Section: Page 8 Of 48 Polymer Chemistrymentioning

confidence: 99%

Surface-initiated controlled radical polymerizations from silica nanoparticles, gold nanocrystals, and bionanoparticles

2015

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In recent years, core/shell nanohybrids containing a nanoparticle core and a distinct surrounding shell of polymer brushes have received extensive attention in nanoelectronics, nanophotonics, catalysis, nanopatterning, drug delivery, biosensing, and many others. From the large variety of existing polymerization methods on the one hand and strategies for grafting onto nanoparticle surfaces on the other hand, the combination of grafting-from with controlled radical polymerization (CRP) techniques has turned out to be the best suited for synthesizing these well-defined core/shell nanohybrids and is known as surface-initiated CRP. Most common among these are surface-initiated atom transfer radical polymerization (ATRP), surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization, and surface-initiated nitroxide-mediated polymerization (NMP). This review highlights the state of the art of growing polymers from nanoparticles using surface-initiated CRP techniques. We focus on mechanistic aspects, synthetic procedures, and the formation of complex architectures as well as novel properties. From the vast number of examples of nanoparticle/polymer hybrids formed by surface-initiated CRP techniques, we present nanohybrid formation from the particularly important and most studied silica nanoparticles, gold nanocrystals, and proteins which can be regarded as bionanoparticles

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Surface‐Initiated Controlled Radical Polymerization from Silica Nanoparticles with High Initiator Density

Cited by 23 publications

References 30 publications

Enhancing Initiation Efficiency in Metal-Free Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP)

Enhancing Initiation Efficiency in Metal-Free Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP)

Polystyrene Brushes on Fully Deuterated Organic Nanoparticles by Surface‐Initiated Nitroxide‐Mediated Radical Polymerization

Surface-initiated controlled radical polymerizations from silica nanoparticles, gold nanocrystals, and bionanoparticles

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