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Cover Picture: Electrochemically Mediated Atom Transfer Radical Polymerization from a Substrate Surface Manipulated by Bipolar Electrolysis: Fabrication of Gradient and Patterned Polymer Brushes (Angew. Chem. Int. Ed. 13/2015) 下载免费PDF全文
Naoki Shida Yuki Koizumi Dr. Hiroki Nishiyama Prof. Dr. Ikuyoshi Tomita Prof. Dr. Shinsuke Inagi 《Angewandte Chemie (International ed. in English)》2015,54(13):3829-3829
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Jeffrey Pyun Tomasz Kowalewski Krzysztof Matyjaszewski 《Macromolecular rapid communications》2003,24(18):1043-1059
Atom transfer radical polymerization (ATRP) is a robust method for the preparation of well‐defined (co)polymers. This process has also enabled the preparation of a wide range of polymer brushes where (co)polymers are covalently attached to either curved or flat surfaces. In this review, the general methodology for the synthesis of polymer brushes from flat surfaces, polymers and colloids is summarized focusing on reports using ATRP. Additionally, the morphology of ultrathin films from polymer brushes is discussed using atomic force microscopy (AFM) and other techniques to confirm the formation of nanoscale structure and organization.
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Simplified Electrochemically Mediated Atom Transfer Radical Polymerization using a Sacrificial Anode 下载免费PDF全文
Sangwoo Park Paweł Chmielarz Armando Gennaro Krzysztof Matyjaszewski 《Angewandte Chemie (International ed. in English)》2015,54(8):2388-2392
Simplification of electrochemically mediated atom transfer radical polymerization was achieved efficiently under either potentiostatic or galvanostatic conditions using an aluminum wire sacrificial anode (seATRP) immersed directly into the reaction flask without separating the counter electrode. seATRP polymerizations were carried out under different applied potentials, Eapps=E1/2, Epc, Epc ?40 mV, and Epc ?80 mV. As the rate of polymerization (Rp) can be modulated by applying different Eapp potentials, more reducing conditions resulted in faster Rp. The polymerization results showed similar narrow molecular‐weight distribution throughout the reactions, similar to results observed for n‐butyl acrylate (BA) polymerization under conventional eATRP. High‐molecular‐weight PBA and diblock copolymers were synthesized by seATRP with more than 90 % monomer conversion. Furthermore, galvanostatic conditions were developed for synthesizing PBA with the two‐electrode system. 相似文献
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Cytocompatible Polymer Grafting from Individual Living Cells by Atom‐Transfer Radical Polymerization 下载免费PDF全文
Ji Yup Kim Dr. Bong Soo Lee Jinsu Choi Beom Jin Kim Ji Yu Choi Prof. Dr. Sung Min Kang Prof. Dr. Sung Ho Yang Prof. Dr. Insung S. Choi 《Angewandte Chemie (International ed. in English)》2016,55(49):15306-15309
A cytocompatible method of surface‐initiated, activator regenerated by electron transfer, atom transfer radical polymerization (SI‐ARGET ATRP) is developed for engineering cell surfaces with synthetic polymers. Dopamine‐based ATRP initiators are used for both introducing the ATRP initiator onto chemically complex cell surfaces uniformly (by the material‐independent coating property of polydopamine) and protecting the cells from radical attack during polymerization (by the radical‐scavenging property of polydopamine). Synthetic polymers are grafted onto the surface of individual yeast cells without significant loss of cell viability, and the uniform and dense grafting is confirmed by various characterization methods including agglutination assay and cell‐division studies. This work will provide a strategic approach to the generation of living cell–polymer hybrid structures and open the door to their application in multitude of areas, such as sensor technology, catalysis, theranostics, and cell therapy. 相似文献
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用原子转移自由基聚合方法制备新型含有高分子金属配合物的无机-有机杂化材料 总被引:5,自引:3,他引:2
近年来,表面引发聚合制备聚合物刷,由于其能控制无机物表面性能,在材料科学方面有广泛的应用前景.在制备聚合物刷的一系列聚合方法中,“活性”/可控自由基聚合,尤其是原子转移自由基聚合(Atom Transfer Radical Polymerization,ATRP)得到广泛使用.它可获得分子量分布较窄的结构规整的聚合物,可将一些功能性的单体引入聚合物体系获得功能聚合物, 相似文献
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Chiaki Yoshikawa Atsushi Goto Norio Ishizuka Kazuki Nakanishi Akio Kishida Yoshinobu Tsujii Takeshi Fukuda 《Macromolecular Symposia》2007,248(1):189-198
The adsorption of proteins on poly(2-hydroxyethyl methacrylate) (PHEMA) brushes was systematically investigated from the viewpoint of the size-exclusion effect of the concentrated brushes. By use of surface-initiated atom transfer radical polymerization, well-defined, concentrated PHEMA brushes were successfully grafted on the inner surface of the silica monolithic column with meso pores of ca. 80 nm as well as a silicon wafer and a quartz crystal microbalance (QCM) chip. By eluting low-polydispersity pullulans with different molecular weight through the modified monolithic column, the concentrated PHEMA brush was characterized and demonstrated to sharply exclude solute molecules with the critical molecular size (size-exclusion limit) comparable to the distance between the nearest-neighboring graft points d. The elution behaviors of proteins with different sizes were studied with this PHEMA-grafted column: the protein sufficiently larger than the critical size was perfectly excluded from the brush layer and separated only in the size-exclusion mode by the meso pores without affinity interaction with the brush surface. Then, the irreversible adsorption of proteins on PHEMA brushes was investigated using QCM by varying graft densities (σ = 0.007, 0.06, and 0.7 chains/nm2) and protein sizes (effective diameter = 2–13 nm). A good correlation between the protein size and the graft density was observed: proteins larger than d caused no significant irreversible adsorption on the PHEMA brushes. Thus, we experimentally substantiated the postulated size-exclusion effect of the concentrated brushes and confirmed that this effect plays an important role for suppressing protein adsorption. 相似文献
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Soyoun An Sang Koo Choi Jang Woo Cho Hyun Tae Kim Jin Woong Kim 《Macromolecular rapid communications》2014,35(15):1356-1361
A robust and straightforward approach is introduced to synthesize inorganic nanoparticles chemically grafted with a zwitterionic poly(2‐methacryroyloxyethylphosphorylcholine) (PMPC) thin layers. The synthesis method is based on the surface‐mediated seeded polymerization. In order to observe how the polymer chain architectures affect colloidal interactions, the zinc oxide nanoparticles are grafted with linear brushes and with a thin hydrogel layer, respectively. The thickness of PMPC shell layers spans a few nanometers. The studies on suspension rheology for the nanoparticles show that the nanoparticles with PMPC brushes show the stronger repulsive force than those with the PMPC gel shell due to the entropic stabilization. When the shear force is applied to the Pickering emulsion produced by assembly of the nanoparticles, it is noticeable that the presence of PMPC brushes on the particles rather enhances the drop‐to‐drop attraction, which presumably stems from the entanglement of polymer chains between the contacted interfacial planes of the emulsion droplets during shearing.
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The quality of solvents of polymers is often described in terms of the Flory χ parameter typically assumed to depend only on the temperature, T. In certain polymer‐solvent systems fitting the experimental data enforces the replacement of (χT) by a concentration‐dependent χeff. In turn, this modifies the swelling and collapse behavior. These effects are studied, in the framework of a mean‐field theory, for isolated coils and for planar brushes. The ϕ dependence of χeff gives rise to three main consequences: (i) shift in the cross‐over between Gaussian and self‐avoidance regimes; (ii) a possibility of first‐order collapse transition for isolated flexible coils; (iii) the possibility of a first‐order phase transition leading to a vertical phase separation within the brush. The discussion relates these effects directly to thermodynamic measurements and does not involve a specific microscopic model. The implementation for the case of poly(N‐isopropylamide) (PNIPAM) brushes is discussed.
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Nan Cheng Omar Azzaroni Sergio Moya Wilhelm T. S. Huck 《Macromolecular rapid communications》2006,27(19):1632-1636
Summary: The atom transfer radical polymerization of [2‐(methacryloyloxy)ethyl]trimethylammonium chloride (METAC) has been studied under different [CuI]/[CuII] ratios. The reaction kinetics is followed by ellipsometry and quartz crystal microbalance and it was found that the reaction speed influences the grafting density of the polymer brushes. High [CuI]/[CuII] ratios, i.e., fast polymerizations, lead to less dense polymer brushes.
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Yue Cui Cheng Tao Suping Zheng Qiang He Sufen Ai Junbai Li 《Macromolecular rapid communications》2005,26(19):1552-1556
Summary: Thermosensitive polymer nanotubes can be fabricated within an aminopropylsilane‐modified porous anodic aluminum oxide membrane by surface‐initiated atom transfer radical polymerization (ATRP) followed by template removal. DSC experiments prove that the synthesized PNIPAM‐co‐MBAA copolymer nanotubes have a reversible thermosensitive behavior. The temperature‐induced changes in dimension and shape of the nanotubes were studied by AFM in real time in an aqueous environment. It indicates that the nanotubes undergo a shape alteration from an “ellipse” to “circular” shape in water upon heating to LCST or above.
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Masahiro Suguro Shigeyuki Iwasa Kentaro Nakahara 《Macromolecular rapid communications》2008,29(20):1635-1639
A practical and polymer‐rich organic radical cathode that contains 80 wt.‐% poly(4‐vinyloxy‐2,2,6,6‐tetramethylpiperidine‐N‐oxyl) (PTVE) and 15 wt.‐% vapor‐grown carbon fiber (VGCF) has been fabricated. The PTVE/VGCF composite electrode shows a reversible redox peak at 3.56 V (vs Li/Li+) in cyclic voltammetry. A coin‐type cell with the PTVE/VGCF composite electrode as the cathode and lithium metal as the anode has also been fabricated and used for charge/discharge measurements. When the cell was discharged at 0.3 mA · cm−2 (1 C), a capacity of 104 mAh · g−1, which is 77% of PTVE's theoretical capacity (135 mAh · g−1), was obtained. When it was discharged at 9.0 mA · cm−2 (30 C), its capacity was 52% of the capacity it had when it was discharged at 0.3 mA · cm−2 (1 C). Even when discharged at 24 mA · cm−2 (80 C), it surprisingly had 32% of the capacity it had when discharged at 0.3 mA · cm−2. The observed rate dependence shows that the polymer‐rich electrode could discharge over 50% of the cell capacity in two minutes and over 30% within one minute.
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为了制备能有效分离富集药草中槲皮素的固相萃取柱,以丙烯酰胺(AM)修饰的碳纳米管为载体,三硫代碳酸酯(DBTTC)为可逆加成-断裂链转移剂(RAFT试剂),槲皮素为模板,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,乙腈为致孔剂,制备了槲皮素分子印迹聚合物,采用红外光谱、扫描电镜和热重分析对印迹材料进行表征,通过高效液相色谱(HPLC)研究聚合物的吸附性能和对底物的特异性识别能力。结果表明,通过活性自由基聚合法合成的多壁碳纳米管表面槲皮素分子印迹聚合具有更好的形态结构和吸附性能,且对槲皮素有很好的特异性识别能力。 相似文献
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Poly(methacryloyloxy ethyltrimethylammonium chloride) (PMETAC), poly(sulfopropylmethacrylate potassium salt), or poly(N‐isopropyl acrylamide) (PNIPAM) brushes are synthesized by means of the atom transfer radical polymerization technique from gold surfaces coated with a monolayer of the initiator ω‐mercaptoundecyl bromo isobutyrate. The brush growth is followed in situ and in real time by the combination of quartz crystal microbalance with dissipation technique (QCM‐D) and spectroscopic ellipsometry in a single device. The combination of QCM‐D and ellipsometry allows for the simultaneous determination of both the acoustic mass, macous, comprising the mass of the polymer and the solvent, and the optical mass, mopt, which corresponds to the polymer mass alone. Brush hydration is calculated from the difference between the values obtained for macous and mopt for each polymer synthesized. Brush hydration is then used to quantify the percentage of water released in the brush during collapse; a 30–40% release of water for PMETAC and PSPM brushes in 1 M NaCl and 80% for PNIPAM brushes when the temperature is increased to values above the lower critical solution temperature is observed. 相似文献
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Jean‐Franois Lutz Hans G. Brner Katja Weichenhan 《Macromolecular rapid communications》2005,26(7):514-518
Summary: The bromine chain ends of well‐defined polystyrene ( = 2 700 g · mol−1, = 1.11) prepared using ATRP were successfully transformed into various functional end groups (ω‐hydroxy, ω‐carboxyl and ω‐methyl‐vinyl) by a two‐step pathway: (1) substitution of the bromine terminal atom by an azide function and (2) 1,3‐dipolar cycloaddition of the terminal azide and functional alkynes (propargyl alcohol, propiolic acid and 2‐methyl‐1‐buten‐3‐yne). The “click” cycloaddition was catalyzed efficiently by the system copper bromide/4,4′‐di‐(5‐nonyl)‐2,2′‐bipyridine. In all cases, 1H NMR spectra indicated quantitative transformation of the chain ends of polystyrene into the desired function.