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Surface-initiated Atom Transfer Radical Polymerization (surface-initiated + atom_transfer_radical_polymerization)
Selected AbstractsSurface-Grafted Gel-Brush/Metal Nanoparticle HybridsADVANCED FUNCTIONAL MATERIALS, Issue 6 2010Edmondo M. Benetti Abstract Polymer brushes are classically defined and are to date employed as assemblies of macromolecules tethered at one end to a surface. The concept of preparing surface-grafted gels by crosslinking such brushes is attractive since it gives rise to new opportunities related to the constraints present in this type of structure. Aiming at the development of nanostructured films possessing precisely adjustable chemical, mechanical, and optical properties, the present article describes the preparation of novel grafted layers based on gel-brush/metal nanoparticle hybrids. These films were synthesized by surface-initiated atom transfer radical polymerization of hydroxyethyl methacrylate with a small percentage of a crosslinker. The swelling, morphological, and mechanical properties of the gel-brushes are shown to be highly dependent on the relative amount of crosslinker used. The gel-brushes are subsequently used as matrixes for the controlled synthesis of silver nanoparticles with overall characteristics that are specifically tunable as a function of the macromolecular structure of the brush template. [source] CdS-Nanoparticle/Polymer Composite Shells Grown on Silica Nanospheres by Atom-Transfer Radical Polymerization,ADVANCED FUNCTIONAL MATERIALS, Issue 3 2005T. Cui Abstract In this paper we describe the combined use of surface-initiated atom transfer radical polymerization (ATRP) and a gas/solid reaction in the direct preparation of CdS-nanoparticle/block-copolymer composite shells on silica nanospheres. The block copolymer, consisting of poly(cadmium dimethacrylate) (PCDMA) and poly(methyl methacrylate) (PMMA), is obtained by repeatedly performing the surface-initiated ATRP procedures in N,N -dimethylformamide (DMF) solution at room temperature, using cadmium dimethacrylate (CDMA) and methyl methacrylate (MMA) as the monomers. CdS nanoparticles with an average size of about 3,nm are generated in situ by exposing the silica nanospheres coated with block-copolymer shells to H2S gas. These synthetic core,shell nanospheres were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), diffuse reflectance UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (XRD). These composite nanospheres exhibit strong red photoluminescence in the solid state at room temperature. [source] Simple Fabrication of Antibody Microarrays on Nonfouling Polymer Brushes with Femtomolar Sensitivity for Protein Analytes in Serum and BloodADVANCED MATERIALS, Issue 19 2009Angus Hucknall A multianalyte antibody array that is spotted on a poly(oligo(ethylene glycol) methacrylate) brush 100,nm thick, grown on glass via surface-initiated atom transfer radical polymerization, has femtomolar limit-of-detection (LOD) of cytokines in serum and whole blood, and a dynamic range of six orders of magnitude for a range of protein analytes. [source] Surface interaction of well-defined, concentrated poly(2-hydroxyethyl methacrylate) brushes with proteinsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2007Chiaki Yoshikawa Abstract The interaction of concentrated polymer brushes with proteins was chromatographically investigated. By the use of surface-initiated atom transfer radical polymerization, a low-polydispersity poly(2-hydroxyethyl methacrylate) (PHEMA) was densely grafted onto the inner surfaces of silica monoliths with mesopores of about 50 and 80 nm in mean size. The graft density reached 0.4,0.5 chains/nm2. The 80-nm-mesopore monolithic column with the concentrated PHEMA brush was characterized through the elution of low-polydispersity pullulans with different molecular weights, clearly showing two modes of size exclusion, that is, one by the mesopores and the other by the brush phase. The latter mode gave a sharp separation with a critical molecular weight (size-exclusion limit) of about 1000. This molecular size of pullulan was comparable to the distance between the nearest-neighbor graft points. The elution behaviors of five proteins of different sizes (bovine serum thyroglobulin, bovine serum immunoglobulin G, bovine serum albumin, horse heart myoglobin, and bovine serum aprotinin) were studied with this PHEMA-grafted column. The smallest protein, aprotinin, with a pullulan-reduced molecular weight slightly larger than the critical value of 1000, was eluted much behind the corresponding pullulan, and this indicated that it barely got into the brush layer, suffering from a strong affinity interaction within the brush. On the other hand, the other four larger proteins were eluted at the same elution volumes as the equivalent pullulans, and this meant that they were perfectly excluded from the brush layer and separated only in the size-exclusion mode by the mesopores without an affinity interaction with the brush surface. This excellent inertness of the concentrated brush in the interaction with the large proteins should afford the system long-term stability against biofouling. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4795,4803, 2007 [source] Poly(N -vinylimidazole)-grafted capillary for electrophoresis prepared by surface-initiated atom transfer radical polymerizationJOURNAL OF SEPARATION SCIENCE, JSS, Issue 17-18 2010Jing Li Abstract A CE method for poly(N -vinylimidazole) (PVI)-grafted capillaries by the surface-initiated atom transfer radical polymerization has been developed. The coating was prepared with N -vinylimidazole as the monomer, 2-bromo-2-methyl- N -[3-(triethoxysilyl) propyl] propanamide (BTPAm) as the initiator and CuCl/CuCl2/2,2,-bipyridine as the catalyst and ligand. The direction and magnitude of EOF in the PVI-grafted capillary were investigated in a pH range of 3.0,9.0. The results indicated that the EOF could be modulated by varying the pH value of the buffer and an anodic EOF was obtained at pH values below 6.5. A significant improvement in reproducibility and reduction of EOF appeared on the PVI-grafted capillary when compared with the uncoated capillary. Furthermore, the polymer coated capillaries were applied to the separations of the inorganic anions, organic acids and basic proteins and baseline separations were achieved with short analysis time and high reproducibility. [source] Controlled Grafting of Poly(methyl methacrylate) Brushes on Poly(vinylidene fluoride) Powders by Surface-initiated Atom Transfer Radical PolymerizationCHINESE JOURNAL OF CHEMISTRY, Issue 2 2009Zhaoqi TANG Abstract Controlled grafting of well-defined polymer brushes of methyl methacrylate (MMA) on the poly(vinylidene fluoride) (PVDF) powders was carried out by the surface-initiated atom transfer radical polymerization (ATRP). The ATRP initiator was anchored on the PVDF surface by alkaline treatment, followed by UV-induced bromination; then methyl methacrylate (MMA) was grafted onto the brominated PVDF by the ATRP technique. The chemical composition changes of PVDF were characterized by Fourier transform-infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). FT-IR and XPS results clearly indicated the successful graft of poly(methyl methacrylate) onto the PVDF surface. [source] Nanoporous, Ultralow-Dielectric- Constant Fluoropolymer Films from Agglomerated and Crosslinked Hollow Nanospheres of Poly(pentafluorostyrene)- block -Poly(divinylbenzene)ADVANCED MATERIALS, Issue 21 2005G.-D. Fu Nanoporous fluoropolymer films with dielectric constants below 2 are prepared via consecutive surface-initiated atom transfer radical polymerizations of pentafluorostyrene (PFS) and divinylbenzene (DVB) on silica nanospheres. After agglomeration of the nanospheres, crosslinking of the nanospheres by UV, and removal of the silica cores (see Figure), a nanoporous fluoropolymer film with a dielectric constant as low as 1.7 is formed. [source] Surface-graft hyperbranched polymer via self-condensing atom transfer radical polymerization from zinc oxide nanoparticlesPOLYMER ENGINEERING & SCIENCE, Issue 9 2007Peng Liu We present the synthesis of hyperbranched polymer grafted zinc oxide (ZnO) hybrid nanoparticles by self-condensing vinyl polymerization (SCVP) via surface-initiated atom transfer radical polymerizations (SI-ATRP) from ZnO surfaces. ATRP initiators were covalently linked to the surfaces of ZnO particles, followed by SCVP of an initiator-monomer ("inimer") which has both a polymerizable group and an initiating group in the same molecule. Well-defined polymer chains were grown from the surfaces to yield hybrid nanoparticles comprised of ZnO cores and hyperbranched polymer shells having multifunctional chlorobenzyl functional end groups. The percentage of grafting (PG%) achieved 429% in 6 h, calculated from the elemental analysis results. The hybrid nanoparticles were also characterized using Fourier transform infrared spectroscopy, UV,vis absorption spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. POLYM. ENG. SCI., 47:1296,1301, 2007. © 2007 Society of Plastics Engineers [source] | |||||||||||||||||||||||||