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1.
Takafumi Mori Tungalag Dong Kouji Yazawa Yoshio Inoue 《Macromolecular rapid communications》2007,28(21):2095-2099
Films of an α‐cyclodextrin/poly(ε‐caprolactone) inclusion complex have been successfully prepared and show high transparency and heat resistance in comparison to the pure polymer film. The physical properties, such as transparency, mechanical properties, and thermal stability, of the α‐CD‐PCL‐IC films are found to depend on the α‐cyclodextrin‐to‐polymer stoichiometry.
2.
PCL microspheres featuring a macroporous morphology and a bone‐bioactive surface have been prepared. ‘Camphene’ was introduced to generate pores within the microsphere network. The pore size was variable from a few to tens to hundreds of µm depending on the Camphene/PCL ratio. Macropores (with sizes >50 µm) could be obtained with a Camphene/PCL ratio exceeding 6. The microsphere surface was further tailored with apatite mineral phase through solution‐mediated precipitation, to endow the interface with bone bioactivity. Rat bone marrow stromal cells attached and spread actively on microspheres and populated well within their macropores. The developed microspheres may be potentially applicable as a cell delivery scaffold for bone tissue engineering.
3.
Summary: The effect of poly(ε‐caprolactone) (PCL) molecular weight on the orientation of crystalline PCL in miscible poly(ε‐caprolactone)/poly(vinyl chloride) (PCL/PVC) blends, melt crystallized under strain, has been studied by a combination of wide angle X‐ray diffraction (WAXD) and small angle X‐ray scattering (SAXS) studies. An unusual crystal orientation with the b‐axis parallel to the stretching direction was observed in miscible PCL/PVC blends with PCL of high molecular weight (>21 000). SAXS showed the presence of nanosize confined PCL in the PCL/PVC blends, which could be preserved at temperatures higher than the Tm of PCL but lower than the Tg of PVC. A mechanism based on the confinement of PCL crystal growth was proposed, which can explain the formation of b‐axis orientation in PCL/PVC blends crystallized under strain.
4.
PCL/clay nanocomposites were prepared by microwave‐assisted in situ ROP of ε‐caprolactone in the presence of either unmodified clay (Cloisite® Na+) or clay modified by quaternary ammonium cations containing hydroxyl groups (Cloisite 30B). This PCL showed significantly improved monomer conversion and molecular weight compared with that produced by conventional heating. An intercalated structure was observed for the PCL/Cloisite Na+ nanocomposites, while a predominantly exfoliated structure was observed for the PCL/Cloisite 30B nanocomposites. Microwave irradiation proved to be an effective and efficient method for the preparation of PCL/clay nanocomposites.
5.
Masakazu Yoshikawa Koji Nakai Hidetoshi Matsumoto Akihiko Tanioka Michael D. Guiver Gilles P. Robertson 《Macromolecular rapid communications》2007,28(21):2100-2105
It is demonstrated that polymeric materials can be directly converted into molecular (chiral) recognition nanofiber membranes by simultaneously applying an electrospray deposition and an alternative molecular imprinting during the membrane preparation process. Polysulfone with a degree of substitution of 0.88 was adopted as the candidate polymeric material for molecularly imprinted nanofiber membranes. Molecularly imprinted nanofiber membranes imprinted by Z‐D ‐Glu recognize the D ‐isomer in preference to the corresponding L ‐isomer and vice versa. The amino acid preferentially incorporated into the membrane is selectively permeated through the membrane by using a concentration gradient as a driving force for membrane transport.
6.
Xiaojin Zhang Fujie Chen Zhenlin Zhong Renxi Zhuo 《Macromolecular rapid communications》2010,31(24):2155-2159
Well‐defined amphiphilic block‐graft copolymers PCL‐b‐[DTC‐co‐(MTC‐mPEG)] with polyethylene glycol methyl ether pendant chains were designed and synthesized. First, monohydroxyl‐terminated macroinitiators PCL‐OH were prepared. Then, ring‐opening copolymerization of 2,2‐dimethyltrimethylene carbonate (DTC) and cyclic carbonate‐terminated PEG (MTC‐mPEG) macromonomer was carried out in the presence of the macroinitiator in bulk to give the target copolymers. All the polymers were characterized by 1H NMR and gel permeation chromatography (GPC). The polymers have unimodal molecular weight distributions and moderate polydispersity indexes. The amphiphilic block‐graft copolymers self‐assemble in water forming stable micelle solutions with a narrow size distribution.
7.
3‐D rose‐like microstructures of polyaniline (PANI), which are self‐assembled from 2‐D nanosheets consisted of 1‐D nanofibers, were synthesized by a template‐free method in the presence of ammonium peroxydisulfate (APS) as both oxidant and dopant under a high relative humidity of 80% for the first time. When the relative humidity increases from 25 to 80%, not only morphology of the micro/nanostructured PANI undergoes a change from 1‐D nanofibers to 2‐D nanosheets to 3‐D rose‐like microstructures, but also increase in crystallinity. It is proposed that a cooperation effect of the oriented water molecules at the vapor–water interface and difference in hydrogen bonding energies between the interface and the bulk induced by the relative high humidity results in the formation of the 3‐D rose‐like microstructures self‐assembled from 2‐D nanosheets. Moreover, the method reported may provide a simple approach for understanding self‐assembly of complex micro/nanostructures of PANI.
8.
Fabrication of Compositional‐Gradient Biodegradable Polymeric Films Showing Self‐Bending Deformation
Kenichi Yamazaki Tungalag Dong Naoki Asakawa Yoshio Inoue Koji Yazawa 《Macromolecular rapid communications》2009,30(6):435-441
A compositional graded film of poly(ε‐caprolactone) (PCL) with 4,4′‐thiodiphenol (TDP), in the film thickness direction, was fabricated by self‐diffusing of TDP in the PCL melt. We found out the self‐bending deformation of the gradient film, which bent into a rolled‐up shape by itself. The initial shape of the film was flat when the sample was quenched from the melt. Upon the fast crystallization of PCL, the gradient film bent to the side with low TDP content. Then, after PCL crystallized the film bent to the opposite direction, that is, to the side with high TDP content. This bending to the TDP rich region was induced by not only the crystallization of PCL but also mass transfer due to the diffusion of TDP from TDP rich region to poor region.
9.
Summary: Single polyelectrolyte component microcapsules and multilayers, exemplified by poly(allylamine hydrochloride) (PAH), have been prepared using a method of glutaraldehyde (GA)‐mediated covalent layer‐by‐layer (LbL) assembly. The GA cross‐linking of the adsorbed PAH results in surfaces covered by reactive aldehyde groups, which can then react with PAH to result in another layer of covalently linked PAH. The repeated assembly of single polyelectrolyte in an LbL manner can be thus achieved. The PAH multilayers can grow linearly along with the layer number, and their thickness can be controlled at the nanometer scale, as verified by UV‐vis absorption spectrometry and ellipsometry. Single polyelectrolyte microcapsules are obtained after removal of the template cores at low pH. The morphology and integrity are confirmed by scanning force microscopy and confocal laser scanning microscopy.
10.
Summary: The copolymerization of ethylene and 1,7‐octadiene (OD) was investigated with a constrained‐geometry catalyst. The 13C NMR spectrum of the copolymer indicated cyclization insertion of the OD unit in the penultimate position after a single ethylene insertion step. This unique insertion mode of OD forms a 1,5‐disubstituted cyclononane unit in the main chain of polyethylene.
11.
Astrid Gugg Christian Gorsche Norbert Moszner Robert Liska 《Macromolecular rapid communications》2011,32(14):1096-1100
Frontal photopolymerization has attracted much attention in the last decade as it allows the curing of thick films. Unfortunately, the use of peroxides, which feature appropriate storage stability, also requires inappropriately high initiation temperatures. Here, a new approach involving a copolymerisation‐induced destabilization of (meth)acrylate‐based peroxides that allows lower front temperatures is presented. The increasing degree of branching next to the carbonyl group lowers the decomposition temperature by at least 20 °C. In classical monomer formulations, sufficient storage stability is confirmed.
12.
Giseop Kwak Hong‐Qing Wang Kyu‐Han Choi Kyu‐Ho Song Soon‐Hak Kim Hyeok‐Soo Kim Sam‐Jong Lee Ho‐Young Cho Eon‐Ju Yu Hyo‐Jeong Lee Eun‐Jung Park Lee‐Soon Park 《Macromolecular rapid communications》2007,28(12):1317-1324
New poly(diphenylacetylene)s with alkoxy and fluoroalkyl groups as electron‐donating and electron‐withdrawing groups, respectively, were synthesized by using a WCl6‐n‐Ph4Sn catalyst. The polymer solutions emitted strong, bluish‐green lights when photo‐excited. The polymers that contained the electron‐donating alkoxy groups showed longer fluorescence‐maximum peaks when compared to the polymers that contained the electron‐withdrawing fluoroalkyl groups. However, such an effect of the substituent on the absorption property was not clearly seen. The emission bands of the solid films did not show any significant red shift, relative to that of the dilute solution.
13.
Chao‐Jian Chen Gong‐Yan Liu Ye‐Ting Shi Cong‐Shan Zhu Shao‐Peng Pang Xiang‐Sheng Liu Jian Ji 《Macromolecular rapid communications》2011,32(14):1077-1081
A novel comb‐like derivative CPEG‐g‐DNQ was prepared by incorporating light responsive 2‐diazo‐1,2‐naphthoquinone (DNQ) groups into the structure of comb‐like poly(ethylene glycol) (CPEG). DLS and TEM results showed that CPEG‐g‐DNQ self‐assembled into spherical micelles with an average size of about 135 nm in water. Upon exposure to light, the micelles could be disrupted because of the conversion of hydrophobic DNQ to hydrophilic 3‐indenecarboylic acid. Additionally, hydrophobic coumarin 102 was successfully loaded into the micelles and photo‐induced ON‐OFF release was demonstrated by fluorescence spectroscopy. MTT assay revealed that the micelles are biocompatible. These photo‐responsive micelles might have great potential for controlled release of hydrophobic drugs.
14.
Smriti Singh Bahar Bingl Agnieszka Morgenroth Felix M. Mottaghy Martin Mller Jrn Schmaljohann 《Macromolecular rapid communications》2013,34(7):562-567
An efficient and simple synthesis approach to form stable 68Ga‐labeled nanogels is reported and their fundamental properties investigated. Nanogels are obtained by self‐assembly of amphiphilic statistical prepolymers derivatised with chelating groups for radiometals. The resulting nanogels exhibit a well‐defined spherical shape with a diameter of 290 ± 50 nm. The radionuclide 68Ga is chelated in high radiochemical yields in an aqueous medium at room temperature. The phagocytosis assay demonstrates a highly increased internalization of nanogels by activated macrophages. Access to these 68Ga‐nanogels will allow the investigation of general behavior and clearance pathways of nanogels in vivo by nuclear molecular imaging.
15.
Yasuhiro Morisaki Hiroaki Imoto Junpei Miyake Yoshiki Chujo 《Macromolecular rapid communications》2009,30(13):1094-1100
We report syntheses of phenylene‐, biphenylene‐, and terphenylene‐layered polymers with a xanthene scaffold by the modified Suzuki‐Miyaura coupling reaction. Their optical properties were studied in detail. The polymer end‐capped by nitrobenzene units, which act as fluorescence quenchers, exhibited the photo‐excited energy transfer from the layered oligophenylenes to the terminal units.
16.
Haibin Zhang Jixiao Wang Zhi Wang Fengbao Zhang Shichang Wang 《Macromolecular rapid communications》2009,30(18):1577-1582
Polyaniline (PANI) micro/nanosheets are successfully synthesized by a template‐free method without using any conventional oxidants. Scanning electron microscopy, transmission electron microscopy, and FT‐IR spectroscopy are applied to characterize the products. By investigating the morphologies and chemical structures of the PANI micro/nanosheets, a possible formation mechanism is proposed. In addition, the influences of experimental parameters, such as the kind of dopant, concentration of aniline, and acidity of reaction system, on the morphologies of the PANI micro/nanosheets have been systematically investigated.
17.
Surawut Chuangchote Toemsak Srikhirin Pitt Supaphol 《Macromolecular rapid communications》2007,28(5):651-659
The present contribution reports the electrospinning of PS/MEH‐PPV fibers with average diameters ranging from 0.165 to 1.190 µm from solutions of PS/MEH‐PPV (PS/MEH‐PPV = 7.5:1, w/w) in 1,2‐dichloroethane. With the addition of pyridinium formate (PF), a volatile organic salt, to the PS/MEH‐PPV solution, the electrospinnability of the resulting solution is enhanced significantly. Both the fiber diameters and the number of fibers are found to increase, while the number of beads is found to decrease with increasing applied electrical potential, the addition of PF, and increasing aging period of the spinning solution after PF addition. FT‐IR analysis shows that ≈15% of the MEH side groups are removed from the MEH‐PPV component in the fibers obtained from the solution that is left to age for 1 month after PF addition, which corresponds well to the loss of mass of ≈7% as observed by thermogravimetric analysis. As a result, partial decomposition of the MEH side groups should be responsible for the observed yellow emission color of the PS/MEH‐PPV fibers obtained from the same solution.
18.
Summary: This work reports a new type of poly(ε‐caprolactone) (PCL) robust hollow sphere with controllable biodegradability, produced by grafting PCL shells from the surface of silica sphere cores and removing the template cores. Bis(ε‐caprolactone‐4‐yl) (BCY) composed of two ε‐caprolactone molecules was used as the crosslinker, which not only greatly strengthened the PCL hollow spheres but also brought hardly any non‐biodegradable component into the system. Solubility experiments and biodegradation tests show that the crosslinked PCL hollow spheres were robust both in water and acetone, and were completely biodegradable with characteristics of controllable biodegradability according to the content of the BCY. The Rhodamine release test indicated that the release rate of encapsulated drugs in the PCL hollow spheres was controlled by diffusion and the biodegradability of the PCL molecules, and the latter mechanism will dominate when more enzymes are involved.
19.
Laetitia Mespouille Magali Vachaudez Fabian Suriano Pascal Gerbaux Olivier Coulembier Philippe Dege Robert Flammang Philippe Dubois 《Macromolecular rapid communications》2007,28(22):2151-2158
Well‐defined amphiphilic PCL‐b‐PDMAEMA block copolymers were successfully synthesized by a combination of ATRP and “click” chemistry following either a commutative two‐step procedure or a straightforward one‐pot process using CuBr · 3Bpy as the sole catalyst. Compared to the traditional coupling method, combining ATRP and click chemistry even in a “one‐pot” process allows the preparation of PCL‐b‐PDMAEMA diblock copolymers characterized by a narrow molecular weight distribution and quantitative conversion of azides and alkynes into triazole functions. Moreover, the amphiphilic character of these copolymers was demonstrated by surface tension measurements and critical micellization concentration was calculated.
20.
Moon Suk Kim Kwang Su Seo Gilson Khang Hai Bang Lee 《Macromolecular rapid communications》2005,26(8):643-648
Summary: The polymerization of ε‐caprolactone (CL) in the presence of HCl · Et2O by an activated monomer mechanism was performed to synthesize diblock or triblock copolymers composed of poly(ethylene glycol) (PEG) and poly(ε‐caprolactone) (PCL). The obtained PCLs had molecular weights close to the theoretical values calculated from the CL to PEG molar ratios and exibited monomodal GPC curves. We successfully prepared PEG and PCL block copolymers by a metal‐free method.