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Polymer‐encapsulated silver nanoparticles were synthesized and sterically stabilized by a new core‐shell type system consisting of poly(S‐alt‐MA)‐graft‐PMMA copolymer that acts as a scaffold for the synthesis of size confined nanoparticles. The graft copolymer is synthesized via ambient temperature ATRP using the CuBr/PMDETA catalytic system at ambient temperature. The graft copolymer is hypothesized to function as a scaffold with the anhydride part interacting strongly with the silver ions, while the PMMA graft functions as a polymer brush that stabilizes the dispersion and prevents the particle aggregation due to a ‘polymer brush effect’. UV absorption and TEM studies confirm that the synthesized silver composite particles have a core‐shell structure.
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Haeng‐Deog Koh Mohammad Changez Jung‐Pil Lee Jae‐Suk Lee 《Macromolecular rapid communications》2009,30(18):1583-1588
An isopropyl myristate (IPM) biocompatible oil and an IPM solution of dodecanethiol‐capped Ag nanoparticles (NPs, 4.5 nm) were used as hydrophobes to suppress the Ostwald ripening of monomer/hydrophobe miniemulsified droplets in a surfactant‐stabilized water phase. The formation of non‐IPM‐encapsulated nanospheres (48 nm) and IPM‐encapsulated nanocapsules (90 nm) were precisely controlled by using a water‐soluble and an oil‐soluble initiator, respectively, in the presence of a pure IPM as a hydrophobe in miniemulsion polymerization. Well‐defined PS nanospheres, on which surfaces were coated with Ag NPs (Ag/PS nanospheres, 65 nm), and nanocapsules encapsulating both NPs and IPM liquid phase (Ag‐IPM/PS nanocapsules, 115 nm) were made by replacing the hydrophobe from pure IPM with Ag/IPM solution. These nanostructures were characterized by transmission and scanning electron microscopes.
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Jun Xu Yujie Fang Peihua Ren Haichang Zhang Erqian Guo Wenjun Yang 《Macromolecular rapid communications》2008,29(16):1415-1420
High molecular weight poly(9,10‐bis(p‐(2‐ethylhexyloxy)phenyl)‐2,6‐anthracenevinylene) (2,6‐PAV) was synthesized with 2,6‐dimethylanthraquinone as a key intermediate. The as‐synthesized polymer is readily soluble in common organic solvents and can be used for spin‐coating. The as‐synthesized polymer exhibits a broad absorption band ranging from 280 to 520 nm and a bluish green emission band with a peak at 500 nm. The polymer shows good thermal stability, and no distinct glass transition is observed. A simple device with the configuration ITO/PEDOT:PSS/2,6‐PAV/Ba/Al showed a turn‐on voltage of 4.8 V and a maximal brightness of 340 cd · m−2.
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Using two‐photon absorption, an array of spots in a dye‐doped polymer film can be bleached, creating a three‐dimensional structure that can be imaged with two‐photon or confocal microscopy. Microscopic deformations resulting from various treatments to the film can be characterized, for example, swelling or shrinking. This technique is demonstrated on dye‐doped poly(vinyl alcohol), in which the effect of swelling with the addition of water to the film is shown.
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Abraham Chemtob Valrie Heroguez Yves Gnanou 《Macromolecular rapid communications》2005,26(21):1711-1715
Summary: Fully linear polyethylene‐based latexes have been prepared by the hydrogenation of polybuta‐1,4‐diene dispersions. The latter were synthesized via dispersion ring‐opening metathesis polymerization of cycloocta‐1,5‐diene, and hydrogenated using RuCl2(PPh3)3 as catalyst, without any further treatment. A high hydrogenation efficiency was achieved as demonstrated by different techniques including DSC, and 1H NMR and FT‐IR spectroscopy. The hydrogenation process could be carried out without detrimental effect on particle size and colloidal stability as evidenced by optical microscopy and light scattering analysis.
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It is shown that the obtained hardness and electrophilicity values of the short length oligomers for a heterocyclic conductive polymer from density functional theory method are quadraticly correlated to those obtained from semiempirical method. Therefore these quantities for all oligomers (up to 15 repeating units) are predicted using the obtained quadratic relations. Both of these predicted quantities for different oligomers are fitted to a new exponential model (Y = Y∞ ed/n) to estimate the electronic properties for the considered conjugated polymers. The calculated band gaps from this model show better agreement with the reported experimental data than those predicted by the previous models. Because of a wide range of variations, the electrophilicity could be a better index for investigating the doping effect in polymers than the hardness.
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Birger Lange Nadine Metz Muhammad Nawaz Tahir Friederike Fleischhaker Patrick Theato Heinz‐Christoph Schrder Werner E. G. Müller Wolfgang Tremel Rudolf Zentel 《Macromolecular rapid communications》2007,28(20):1987-1994
Colloidal photonic crystals were prepared from monodisperse core–shell particles. The shell is hereby formed from a functional monomer, such as glycidylmethacrylate or different reactive ester monomers, which can perform chemical reactions and the core from a standard monomer, which yields highly monodisperse colloids. It was possible to crystallize the core–shell particles into artificial opals with excellent optical properties. Reactions on the functional surface of the colloids were carried out, which lead to a dramatic rise in the mechanical stability or to a functionalization of His‐tagged silicatein, which acts as nanoreactor to synthesize and immobilize gold nanoparticles from auric acid onto the core–shell colloids.
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Mauro Zammarano Jeffrey W. Gilman Marc Nyden Eli M. Pearce Menachem Lewin 《Macromolecular rapid communications》2006,27(9):693-696
Summary: Evidence of clay migration from the core to the surface of poly(propylene)/montmorillonite nanocomposites is provided. A three‐ to fivefold increase in the clay concentration of the surface is obtained during isothermal heating in oxidative atmosphere. The mechanism of migration is investigated by means of attenuated total reflectance Fourier transform infrared spectrometry. It is shown that oxygen plays a fundamental role in the migration mechanism.
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Wu Aik Yee Shanxin Xiong Guoqiang Ding Chien Anh Nguyen Pooi See Lee Jan Ma Masaya Kotaki Ye Liu Xuehong Lu 《Macromolecular rapid communications》2010,31(20):1779-1784
A reverse‐barrier technique is used to enable the treatment of electrospun poly(vinylidene fluoride) nanofibrous membranes with supercritical carbon dioxide. The treatment induces the formation of nanopores and extended‐chain β crystallites of small lateral dimensions in the nanofibers. It also creates interfiber junctions, resulting in a remarkable improvement in mechanical properties of the membranes. The treated membranes are able to retain their shape very well after loading with an ionic liquid (IL). The ionic conductivity of the IL‐loaded membrane is very close to that of the neat IL.
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Jian Wang Mohammad Masoud Mohebi Julian R. G. Evans 《Macromolecular rapid communications》2005,26(4):304-309
Summary: Combinatorial exploration of material compositions and associated informatics having influenced medicinal chemistry are now transforming the material sciences. In ceramic science, both thin and thick film combinatorial techniques are available. Ink‐jet printing provides a pathway to the latter. Mixing behind the nozzle and in front of the nozzle in well plates is described here. Such instruments are described and compared, and compositional calibration details for both are given.
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Shy Chyi Wuang Koon Gee Neoh En‐Tang Kang Daniel W. Pack Deborah E. Leckband 《Macromolecular rapid communications》2007,28(7):816-821
The preparation of polypyrrole/Fe3O4 nanospheres by a facile mini‐emulsion polymerization method is investigated using poly(ethylene glycol), poly(ethylene oxide), poly(vinyl alcohol), and hyaluronic acid as surfactants. Hyaluronic acid is deemed the most suitable surfactant since it results in well‐dispersed nanospheres of 80–100 nm, and offers the advantages of biocompatibility, cell adhesive property, and the availability of functional groups for attachment of other molecules. These polypyrrole/Fe3O4 nanospheres are magnetic and can be further functionalized with a cancer antibody, herceptin. Our results show that this combination of hyaluronic acid and herceptin results in high specific uptake of the nanospheres by cancer cells.
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Jun Fu Xiaoshuang Feng Yanchun Han Caiyuan Pan Yuming Yang Binyao Li 《Macromolecular rapid communications》2003,24(8):487-491
A two‐armed polymer with a crown ether core self‐assembles to produce macroporous films with pores perpendicularly reaching through the film down to the substrate. A possible assembling mechanism is discussed. The pore size can be conveniently adjusted by changing the solution concentration. These through‐hole macroporous films provide a template for fabricating an array of Cu nanoparticle aggregates.
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Guohua Chen Malancha Gupta Kelvin Chan Karen K. Gleason 《Macromolecular rapid communications》2007,28(23):2205-2209
Furan ring‐functionalized solid surfaces are achieved by the initiated chemical vapor deposition (iCVD) method, a solvent‐free process to form films under mild conditions. The polymerization of furfuryl methacrylate monomer is initiated by a resistively heated filament wire. The functionality of the furan group in the iCVD film enabled Diels–Alder chemistry with 4‐phenyl‐1,2,3‐triazolin‐3,5‐dione (N‐PTD).
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Casting a photopolymer solution to form a film, followed by imagewise photoirradiation and subsequent wet development, leads to photolithography. Whereas the wet development is achievable with aqueous alkali, the emission of an organic solvent as a volatile organic compound (VOC) is usually inevitable during the film casting because ingredients of common photopolymers are insoluble in water. We show here a prototype of water‐borne photopolymers dispersed with milled nanoparticles of poorly water‐soluble photoacid generators (PAGs), which undergo solid‐state photolysis to liberate a photoacid to make a poly(vinyl alcohol) film insoluble in water with the aid of an acid‐sensitive crosslinking reagent. The photolysis of onium‐type PAGs is sensitized in the solid state simply by comilling with water‐insoluble sensitizers to extend spectral sensitivity of this kind of photopolymers. Fluorescence quenching measurements revealed that the solid‐state sensitization occurs through exciton migration in sensitizer particles followed by electron transfer to PAG particles.
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Shinji Ando Robin K. Harris Paul Hazendonk Philip Wormald 《Macromolecular rapid communications》2005,26(5):345-356
Summary: Fluorine‐19 NMR spectra of solids have some special features, which are discussed in this article. In particular, they generally contain two abundant spin baths (protons and fluorine nuclei). This situation throws up some special operational requirements, as does the study of heterogeneous samples. The relaxation characteristics of heterogeneous systems, which are briefly described herein, frequently permit the use of specific pulse sequences to obtain subspectra for individual components. Various possible selective sequences for use in fluorinated heterogeneous organic solids are listed and their actions rationalized on the basis of molecular mobility. Semicrystalline hydrogen‐containing fluoropolymers form especially suitable systems for such operations, and in order to understand their domain structures it is essential to obtain subspectra of the amorphous and crystalline domains. Examples are given of the use of selective pulse sequences for studying fluoropolymers, especially for poly(vinylidene fluoride) (PVDF) and the copolymer P(VDF75/TrFE25) (TrFE = trifluoroethylene).