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This report describes the remarkably rapid synthesis of polymer brushes under mild conditions (50 degrees C) using surface-initiated polymerization. The highly active atom transfer radical polymerization catalyst Cu(I)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane allows synthesis of 100 nm thick poly(tert-butyl acrylate) brushes from initiator-modified Au surfaces in just 5 min. Using the same catalyst, polymerization of 2-hydroxyethyl methacrylate and methyl methacrylate yielded 100 nm thick films in 10 and 60 min, respectively. Such growth rates are an order of magnitude greater than those for traditional free-radical polymerizations initiated from surfaces. These polymerizations also retain some features of controlled radical polymerizations, such as the ability to form block copolymer brushes. 相似文献
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Living polymerization is most often observed in systems where the growing species are ions. In such systems the chain ends do not react to each other due to elestrostactic repulsion, but only to monomers allowing, this way, the control in structure of the formed polymer. Free radicals, which are the growing species in the radical polymerization, easely undergo combination and prevent a living radical polymerization. Thus, a great challenge to polymer science was in meeting a system that offered to the radical polymerization a radical stabillization alike in ionic polymerizations. At the same time, the radicals should undergo rapid propagation and should not be able to initiate new chains, in a controlled reaction. Some succesfull techniques of living/controlled radical polymerization, such as stable free radical polymerization (SFRP), mediated by nitroxide, INIFERTER and atom transfer polymerization (ATRP) will be overviewed here, as well as their application to the synthesis of liquid crystalline polymers. 相似文献
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Organotellurium‐mediated living radical polymerizations (TERPs) and organostibine‐mediated living radical polymerizations (SBRPs) provide well‐defined polymers with a variety of polar functional groups via degenerative chain‐transfer polymerization. The high controllability of these polymerizations can be attributed to the rapid degenerative‐transfer process between the polymer‐end radicals and corresponding dormant species. The versatility of the methods allows the synthesis of AB diblock, ABA triblock, and ABC triblock copolymers by the successive addition of different monomers. This review summarizes the current status of TERP and SBRP. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1–12, 2006 相似文献
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Tsuyoshi Nishikawa Makoto Ouchi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(36):12565-12569
The ability of isopropenyl boronate pinacol ester to serve as a monomer in radical polymerizations was established and exploited for the synthesis of polymers that are difficult to access using other polymerization techniques. Although the monomer exhibits an α‐methyl‐substituted unconjugated structure, which is usually unfavorable for radical propagation, both free and controlled radical polymerizations smoothly afford the corresponding polymers. A density‐functional‐theory‐based investigation revealed that the boron atom moderately stabilizes the radical species, which leads to the suppression of the degradative chain transfer to the α‐methyl groups, and thus guides the reaction towards the radical polymerization. The boronyl pendants, which are directly attached to the polymer backbone, can be replaced with ‐OH or ‐NH2 to yield poly(α‐methyl vinyl amine) or poly(α‐methyl vinyl alcohol), which has been inaccessible by conventional synthetic methods. 相似文献
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Per B. Zetterlund Fawaz Aldabbagh Masayoshi Okubo 《Journal of polymer science. Part A, Polymer chemistry》2009,47(15):3711-3728
Supercritical carbon dioxide (scCO2) is an inexpensive and environmentally friendly medium for radical polymerizations. ScCO2 is suited for heterogeneous controlled/living radical polymerizations (CLRPs), since the monomer, initiator, and control reagents (nitroxide, etc.) are soluble, but the polymer formed is insoluble beyond a critical degree of polymerization (Jcrit). The precipitated polymer can continue growing in (only) the particle phase giving living polymer of controlled well‐defined microstructure. The addition of a colloidal stabilizer gives a dispersion polymerization with well‐defined colloidal particles being formed. In recent years, nitroxide‐mediated polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible addition fragmentation chain transfer (RAFT) polymerization have all been conducted as heterogeneous polymerizations in scCO2. This Highlight reviews this recent body of work, and describes the unique characteristics of scCO2 that allows composite particle formation of unique morphology to be achieved. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3711–3728, 2009 相似文献
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An effective approach is described for the synthesis of binary patterned polymer brushes using a combination of capillary force lithography and surface-initiated polymerization. First, the approach calls for an ultrathin polystyrene (PS) mask to be deposited, in a pattern, over a surface to which a layer of polymerization initiator has already been anchored. Next, surface-initiated atom transfer radical polymerization (ATRP) is performed. This can graft the initial polymer brush onto those areas of the surface unprotected by the PS mask. After grafting is complete, the PS mask is removed and a second brush is synthesized on the newly exposed areas. 相似文献
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Living radical polymerization of diisopropyl fumarate to obtain block copolymers containing rigid poly(substituted methylene) and flexible polyacrylate segments 下载免费PDF全文
Living radical polymerizations of diisopropyl fumarate (DiPF) are carried out to synthesize poly(diisopropyl fumarate) (PDiPF) as a rigid poly(substituted methylene) and its block copolymers combined with a flexible polyacrylate segment. Reversible addition‐fragmentation chain transfer (RAFT) polymerization is suitable to obtain a high‐molecular‐weight PDiPF with well‐controlled molecular weight, molecular weight distribution, and chain‐end structures, while organotellurium‐mediated living radical polymerization (TERP) and reversible chain transfer catalyzed polymerization (RTCP) give PDiPF with controlled chain structures under limited polymerization conditions. In contrast, controlled polymerization for the production of high‐molecular‐weight and well‐defined PDiPF is not achieved by atom transfer radical polymerization (ATRP) and nitroxide‐mediated radical polymerization (NMP). The block copolymers consisting of rigid poly(substituted methylene) and flexible polyacrylate segments are synthesized by the RAFT polymerization. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2136–2147 相似文献
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Yang WJ Cai T Neoh KG Kang ET Dickinson GH Teo SL Rittschof D 《Langmuir : the ACS journal of surfaces and colloids》2011,27(11):7065-7076
Barnacle cement (BC) was beneficially applied on stainless steel (SS) to serve as the initiator anchor for surface-initiated polymerization. The amine and hydroxyl moieties of barnacle cement reacted with 2-bromoisobutyryl bromide to provide the alkyl halide initiator for the surface-initiated atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate (HEMA). The hydroxyl groups of HEMA polymer (PHEMA) were then converted to carboxyl groups for coupling of chitosan (CS) to impart the SS surface with both antifouling and antibacterial properties. The surface-functionalized SS reduced bovine serum albumin adsorption, bacterial adhesion, and exhibited antibacterial efficacy against Escherichia coli (E. coli). The effectiveness of barnacle cement as an initiator anchor was compared to that of dopamine, a marine mussel inspired biomimetic anchor previously used in surface-initiated polymerization. The results indicate that the barnacle cement is a stable and effective anchor for functional surface coatings and polymer brushes. 相似文献
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Copper(II)-mediated activators regenerated by electron transfer for atom transfer radical polymerization of methyl methacrylate (MMA) was successfully carried out in a limited amount of air in the presence of 2-(8-heptadecenyl)-4,5-dihydro-1H-Imidazole-1-ethylamine as ligand that served not only as ligand but also as reducing agents. Reduction of Cu(II) to Cu(I) by an excess amount of nitrogen-based ligand was followed by UV–visible spectroscopy. The kinetics of the polymerizations and effect of different polymerization conditions are investigated. It is found that the polymerization of MMA can be conducted well even if the amount of Cu(II) is as low as 1 mol% catalyst relative to initiator. The results of the polymerizations demonstrate the features of “living”/controlled free-radical polymerization, such as the number-average molecular weights being close to their corresponding theoretical values and increasing linearly with monomer conversion, and narrow molecular weight distributions. Chain extension of poly(methyl methacrylate)s with MMA was successful and demonstrated well-maintained end-group functionality. 相似文献
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Fulghum TM Patton DL Advincula RC 《Langmuir : the ACS journal of surfaces and colloids》2006,22(20):8397-8402
We report the synthesis of ternary polymer particle material systems composed of (a) a spherical colloidal particle core, coated with (b) a polyelectrolyte intermediate shell, and followed by (c) a grafted polymer brush prepared by surface-initiated polymerization as the outer shell. The layer-by-layer (LbL) deposition process was utilized to create a functional intermediate shell of poly(diallyl-dimethylammonium chloride)/poly(acrylic acid) multilayers on the colloid template with the final layer containing an atom transfer radical polymerization (ATRP) macroinitiator polyelectrolyte. The intermediate core-shell architecture was analyzed with FT-IR, electrophoretic mobililty (zeta-potential) measurements, atomic force microscopy, and transmission electron microscopy (TEM) techniques. The particles were then utilized as macroinitiators for the surface-initiated ATRP grafting process for poly(methyl methacrylate) polymer brush. The polymer grafting was confirmed with thermo gravimetric analysis, FT-IR, and TEM. The polymer brush formed the outermost shell for a ternary colloidal particle system. By combining the LbL and surface-initiated ATRP methods to produce controllable multidomain core-shell architectures, interesting functional properties should be obtainable based on independent polyelectrolyte and polymer brush behavior. 相似文献
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Wang JY Chen W Liu AH Lu G Zhang G Zhang JH Yang B 《Journal of the American Chemical Society》2002,124(45):13358-13359
A promising strategy for the controlled synthesis of inorganic/polymeric nanocomposites may be sustained by fabricating cross-linked PbS nanoparticles/polymer composite thin films through combining surface-initiated atom transfer radical polymerization (ATRP) and gas/solid reaction. The introduction of Pb ions through the extension of surface-initiated ATRP to the monomers containing metal ions provides an opportunity for generating nanoparticles on the substrate. 相似文献
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Qin Zhang Zhengbiao Zhang Wenxiang Wang Jian Zhu Zhenping Cheng Nianchen Zhou Wei Zhang Xiulin Zhu 《Journal of polymer science. Part A, Polymer chemistry》2012,50(7):1424-1433
In this work, cupric oxide (CuO) or cuprous oxide (Cu2O) was used as the catalyst for the single electron transfer‐reversible addition‐fragmentation chain transfer (SET‐RAFT) polymerization of methyl methacrylate in the presence of ascorbic acid at 25 °C. 2‐Cyanoprop‐2‐yl‐1‐dithionaphthalate (CPDN) was used as the RAFT agent. The polymerization occurred smoothly after an induction period arising from the slow activation of CuO (or Cu2O) and the “initialization” process in RAFT polymerization. The polymerizations conveyed features of “living”/controlled radical polymerizations: linear evolution of number‐average molecular weight with monomer conversion, narrow molecular weight distribution, and high retention of chain end fidelity. From the polymerization profile, it was deduced that the polymerization proceeded via a conjunct mechanism of single electron transfer‐living radical polymerization (SET‐LRP) and RAFT polymerization, wherein CPDN acting as the initiator for SET‐LRP and chain transfer agent for RAFT polymerization. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
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Free radical polymerization of acrylonitrile (AN) in ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), 2,2;m1-azobisisobutyronitrile (AIBN) as initiator was investigated. Early investigations on polymerizations using ionic liquids indicate that they serve as especially good solvents to achieve high molecular weight polymers. Free radical polymerizations result in higher molecular weight polymers, for ionic liquids have low chain transfer constants and act to stabilize the active radical during the process of polymerization. The thermal stability of polymers synthesized in ionic liquids have be improved obviously than that in traditional solvents. 相似文献
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In Situ Monitoring of RAFT Polymerization by Tetraphenylethylene‐Containing Agents with Aggregation‐Induced Emission Characteristics 下载免费PDF全文
Dr. Shunjie Liu Dr. Yanhua Cheng Haoke Zhang Zijie Qiu Dr. Ryan T. K. Kwok Dr. Jacky W. Y. Lam Prof. Ben Zhong Tang 《Angewandte Chemie (International ed. in English)》2018,57(21):6274-6278
A facile and efficient approach is demonstrated to visualize the polymerization in situ. A group of tetraphenylethylene (TPE)‐containing dithiocarbamates were synthesized and screened as agents for reversible addition fragmentation chain transfer (RAFT) polymerizations. The spatial‐temporal control characteristics of photochemistry enabled the RAFT polymerizations to be ON and OFF on demand under alternating visible light irradiation. The emission of TPE is sensitive to the local viscosity change owing to its aggregation‐induced emission characteristic. Quantitative information could be easily acquired by the naked eye without destroying the reaction system. Furthermore, the versatility of such a technique was well demonstrated by 12 different polymerization systems. The present approach thus demonstrated a powerful platform for understanding the controlled living radical polymerization process. 相似文献