共查询到20条相似文献,搜索用时 15 毫秒
1.
Christophe Djugnat David Haloan Gleb B. Sukhorukov 《Macromolecular rapid communications》2005,26(12):961-967
Summary: Reversible pH‐induced swelling of (PAH/PSS) polyelectrolyte microcapsules is accompanied by increased porosity, making them permeable to poly(acrylic acid) (PAA) at pH values higher than 11.2. This pH‐switchable permeability was used to encapsulate the polyanion in alkaline conditions. Relationship between starting PAA concentration in solution and amount finally being encapsulated has been established and can be used further as calibration curve. A desired amount of encapsulated polymer in the picogram range per capsule can be achieved. The loaded capsules were then used as microreactors by forming a complex between the PAA and Ca2+ ions.
2.
Summary: A water‐soluble gold nanoparticle aggregate 2 was prepared by chloroauric acid and a polypseudorotaxane 1 of mono‐6‐thio‐β‐cyclodextrin with poly(propylene glycol) bis(2‐aminopropyl ether) ( ≈ 2 000) in the presence of sodium borohydride in N,N‐dimethylformamide (DMF) solution. The investigative results indicated that the gold nanoparticle aggregate 2 might act as an efficient DNA‐cleavage reagent.
3.
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.
4.
Sei‐ichi Ishii Rieko Furuyama Naoto Matsukawa Junji Saito Makoto Mitani Hidetsugu Tanaka Terunori Fujita 《Macromolecular rapid communications》2003,24(7):452-456
The catalytic properties of bis(phenoxy‐imine) Zr and Hf complexes incorporating perfluorophenyl groups with methylaluminoxane were investigated. The fluorinated complexes produced far higher‐molecular‐weight polyethylenes and ethylene/propylene copolymers with increased activities compared with the non‐fluorinated congeners. Moreover, the fluorinated complexes displayed a higher incorporation ability for propylene.
5.
Christoph Tonhauser Daniel Wilms Yasmin Korth Holger Frey Christian Friedrich 《Macromolecular rapid communications》2010,31(24):2127-2132
Are hyperbranched polymers capable of forming entanglements? This is the central issue of this contribution. Hyperbranched polyglycerol (hbPG) samples with different molecular weights (600–106 000 g · mol−1), narrow polydispersities (1.2–1.8) and high degrees of branching (≈0.6) were prepared by anionic ring‐opening polymerization. The viscoelastic properties of these polymers with respect to molecular architecture and molar mass were investigated. At low molecular weights “classical” scaling behavior between zero shear viscosity and molecular weight can be observed, whereas between 3 000 and 10 000 g · mol−1 a plateau‐like area is found. The results indicate entanglement dynamics when exceeding a critical molar mass ( ≈ 20 000 g · mol−1) due to entangled hyperbranched polyglycerols.
6.
The intercalation of aluminosilicate clays proceeds via a critical conformation change. Ion exchange of the poly(oxypropylene)diamine salts allows widening of the clay layers from 12 Å to 20 Å and then a sharp increase to 58 Å. The data indicate a critical conformation change of the intercalated amines, thus providing a new way for manipulating nanomaterials and control of polymer conformations in layered silicate confinement.
7.
Hitoshi Sashiwa Naoki Yamamori Yoshifumi Ichinose Junzo Sunamoto Sei‐ichi Aiba 《Macromolecular bioscience》2003,3(5):231-233
The Michael reaction of chitosan with acrylic acid was carried out successfully, even in water alone as the reaction medium. As a consequence of its good solubility in water, the reaction product, N‐carboxyethylchitosan, showed excellent biodegradable properties with standard activated sludge.
8.
Summary: Amphiphilic hyperbranched polyester (H20‐AM) with methacrylate end groups was synthesized based on hyperbranched aliphatic polyester (Boltorn™ H20). Narrow‐dispersed crosslinkable vesicles were obtained by dissolving H20‐AM in water, and characterized by laser light scattering and TEM. The hollow structural vesicle is composed of around 350 H20‐AM molecules, having a radius of around 40 nm and of 1.9 × 106 g · mL−1. The vesicles were fixed by crosslinking of methacrylate groups to form shape‐persistent structures.
9.
Yayoi Ozawa Shin‐ichi Sawada Nobuyuki Morimoto Kazunari Akiyoshi 《Macromolecular bioscience》2009,9(7):694-701
Highly branched cyclic dextrin derivatives (CH‐CDex) that are partly substituted with cholesterol groups have been synthesized. The CH‐CDex forms monodisperse and stable nanogels with a hydrodynamic radii of ≈10 nm by the self‐assembly of 4–6 CH‐CDex macromolecules in water. The CH‐CDex nanogels spontaneously trap 10–16 molecules of fluorescein isothiocyanate‐labeled insulin (FITC‐Ins). The complex shows high colloidal stability: no dissociation of trapped insulin is observed after at least 1 month in phosphate buffer (0.1 M , pH 8.0). In the presence of bovine serum albumin (BSA, 50 mg · mL?1), which is a model blood system, the FITC‐Ins trapped in the nanogels is continuously released (≈20% at 12 h) without burst release. The high‐density nanogel structure derived from the highly branched CDex significantly affects the stability of the nanogel–protein complex.
10.
11.
Caixia Cheng Ye Tian Yanqiao Shi Rupei Tang Fu Xi 《Macromolecular rapid communications》2005,26(15):1266-1272
Summary: Fabrication of honeycomb‐patterned films from amphiphilic dendronized block copolymer (PEO113‐b‐PDMA82) by ‘on‐solid surface spreading’ and ‘on‐water spreading’ method is reported. Highly ordered honeycomb films with quasi‐horizontally paralleled double‐layered structure can be fabricated by the on‐solid surface spreading method. This work raises the possibility that such structures can be formed in amphiphilic dendronized block copolymers and extends the family of source materials.
12.
Yuta Saito Takahito Kawano Masatsugu Shimomura Hiroshi Yabu 《Macromolecular rapid communications》2013,34(8):630-634
Porous surface patterns are used in a wide variety of practical applications. Honeycomb‐patterned porous polymer films are good templates for preparing porous surfaces due to their simple fabrication and the arrangement of pores on the surface. Catechol groups include in adhesive protein of mussels have attracted much attention due to their highly and substrate‐independent adhesive properties. In this paper, highly and substrate‐independent adhesive honeycomb‐patterned porous polymer films are prepared by using amphiphilic copolymer having catechol moieties. Furthermore, porous surface patterns are transferred on various organic or inorganic substrates by wet etching with using adhesive honeycomb films as templates.
13.
14.
Emilio Scamporrino Placido Mineo Sandro Dattilo Daniele Vitalini Emanuela Spina 《Macromolecular rapid communications》2007,28(15):1546-1552
Some new water‐soluble bis‐porphyrins, constituted of two porphyrin units spaced by means of aliphatic bridges of different lengths, were synthesized and characterized by MALDI‐TOF mass spectrometry, 1H NMR and UV‐vis spectroscopy. The hydrosolubility of these uncharged compounds was guaranteed from the presence of six long PEG chains bound on the peripheral positions of the two porphyrins. Cobalt and zinc derivatives were also prepared. In the case of Co‐bis‐porphyrin, the appearance of induced circular dichroism (ICD) signals in water solution confirmed the formation of stable complexes with some amino acids, in which the bis‐porphyrin behaves like molecular tweezers.
15.
16.
Mahriah E. Alf Paul D. Godfrin T. Alan Hatton Karen K. Gleason 《Macromolecular rapid communications》2010,31(24):2166-2172
A novel thermally responsive copolymer p(NIPAAm‐co‐DEGDVE) is synthesized using the substrate independent method of iCVD and exhibits a sharp lower critical solution temperature (LCST) transition centered at ≈28.5 ± 0.3 °C determined via quartz crystal microbalance measurements with dissipation monitoring (QCM‐D). Swelling with water below the LCST produces a reversible change of ≈3× in film thickness. The layer is conformal on nanostructured surfaces including MWCNT forests and electrospun nanofiber mats. Modified planar substrates exhibit ≈30°change in static contact angle over the LCST, while through conformal coating on nanostructured substrates changes in static contact angle up to 135° are achieved. Additionally, coated surfaces exhibit temperature sensitive BSA adsorption measured by QCM‐D and is reversible as shown through fluorescence imaging of a coated electrospun nanofiber mat.
17.
Ken Cham‐Fai Leung 《Macromolecular theory and simulations》2009,18(6):328-335
The theoretical postulations of mass spectral quantities and distributions of the three dynamic combinatorial libraries (DCLs) of mechanically interlocked dendrimers ([4]rotaxanes, molecular weight up to 8 800 kDa) have been investigated. The number of different dendrimers in the three library mixtures is 4, 10, and 20. The theoretical postulations involve their macroconstants in a combination with statistical distribution, binding constant, steric, and hydrophobic effects. We found out that the mass spectral intensities which relate to the dendrimer quantities in a competitive mixture are not random, but with a predictable trend in terms of their macroconstants. This postulation agrees significantly well with most of the experimentally determined mass spectral intensities in the dendrimer mixtures.
18.
Block copolymers were prepared via RAFT polymerization with P(PEGMEMA) as the hydrophilic block to form micelles for the controlled delivery of ABZ. The group contribution method was used to estimate the partial solubility parameters for ABZ and various polymers as potential core‐forming block to achieve optimum compatibility. Different ratios between MMA and LMA, a non‐compatible monomer, were prepared. Cytotoxicity tests revealed a high toxicity of the ABZ‐loaded micelle resulting in 80% cell deaths at a micelle concentration of 10 µg · mL?1. Cellular uptake of micelles has been studied using fluorescently labeled micelles, showing that a large fraction of micelles is readily taken up by OVCAR‐3 cells. RGD‐conjugated micelles were prepared and showed an increased cellular uptake.
19.
Nobuyuki Morimoto Takafumi Ohki Kimio Kurita Kazunari Akiyoshi 《Macromolecular rapid communications》2008,29(8):672-676
Rapidly shrinking poly(N‐isopropyl acrylamide) (PNIPAM) hydrogels are prepared by crosslinking with self‐assembled nanogels that consist of cholesteryl‐ and methacryloyl‐substituted pullulan (CHPMA). The CHPMA nanogel (Rh = 26.4 nm) was used as a crosslinker for a hydrophilic nanodomain. Transmission electron microscopy images of the nanogel‐crosslinked PNIPAM hydrogel reveal a well‐defined nanoporous structure. The nanogel‐crosslinked PNIPAM hydrogel shows rapid shrinking based on its structure. The shrinking half‐time was ≈2 min, which is about 3 400 times faster than that of a PNIPAM hydrogel crosslinked by methylene(bisacrylamide).
20.
Zhiyong Zhang Quli Fan Pengfei Sun Lulin Liu Xiaomei Lu Bo Li Yiwu Quan Wei Huang 《Macromolecular rapid communications》2010,31(24):2160-2165
Grafted conjugated polyelectrolytes were synthesized for the first time and characterized. The polymers demonstrated properties of a convenient and efficient protocol for creating Hg2+ sensors. The unique character of the new material comes from an anionic counterion nature with no external cofactors, and imparts high selectivity and fast detection for mercury ion in a fluorescence probe. The concept may be potentially applied to create new sensors for monitoring other ions.