共查询到20条相似文献,搜索用时 46 毫秒
1.
Ning Zhao Jian Xu Qiongdan Xie Lihui Weng Xinglin Guo Xiaoli Zhang Lianghe Shi 《Macromolecular rapid communications》2005,26(13):1075-1080
Summary: A superhydrophobic coating was facilely fabricated in one step by casting bisphenol A polycarbonate (PC) solution under moisture. Vapor‐induced phase separation occurred during the solidifying process and a rough surface with a micro‐nano‐binary structure (MNBS) similar to the microstructure shown on lotus leaf was formed.
2.
Jingjing Xu Jianchen Hu Xinfeng Liu Xiaohui Qiu Zhixiang Wei 《Macromolecular rapid communications》2009,30(16):1419-1423
A facile approach to prepare poly(3‐hexylthiophene) (P3HT)/cadmium selenide quantum dot (CdSe QD) hybrid coaxial nanowires by a stepwise self‐assembly process is reported. P3HT nanowires of ≈20 nm diameter are first prepared by self‐assembly in a poor solvent such as cyclohexanone, and then as‐prepared CdSe QDs are deposited compactly onto the P3HT nanowires by non‐covalent interactions between P3HT and CdSe. When illuminated with white light, the hybrid nanowires show enhanced photoconductivity compared with the pristine P3HT nanowires and the blended nanocomposites.
3.
Ya‐Jun Cheng Sabine Renker Zaicheng Sun Jochen S. Gutmann 《Macromolecular rapid communications》2005,26(8):613-619
Summary: Homogeneous films of PI‐b‐PDMAEMA are prepared on top of silicon (100) substrates. The free film surface shows microdomains of PDMAEMA within a PI matrix. These microdomains act as templates for the highly site‐selective synthesis of metal nanoparticles via palladium‐catalyzed electroless nickel plating. The particle formation is studied by atomic force microscopy in tapping mode and implications for a redox reaction and a nanoparticle growth mechanism on the surface of nanopatterned films are discussed.
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The six‐armed polystyrenes and poly(methyl methacrylate)s with a triphenylene core showed different self‐assembling patterns, isolated cylinders for polySt on mica and highly ordered cylindrical pores for polyMMA on a silicon wafer. With a decrease of polymer concentration in tetrahydrofuran (THF), the size and height of cylinders decreased for polySt, but for polyMMA, the size and depth of the cylindrical pores increased. Slow evaporation of the solvent and a low molecular weight favored the formation of regular patterns.
6.
Youyong Xu Andreas Walther Axel H. E. Müller 《Macromolecular rapid communications》2010,31(16):1462-1466
A supramolecular complex between an ionic monomer 3‐sulfopropyl methacrylate (SPMAK) and crown ether 18‐crown‐6 (18C6) has been employed to prepare a strong anionic cylindrical polyelectrolyte brush poly(potassium 3‐sulfopropyl methacrylate) (PSPMAK) by atom transfer radical polymerization (ATRP) in polar solvent dimethyl sulfoxide (DMSO). This strategy solved the problem of the solubilities of the incompatible hydrophobic poly‐initiator and hydrophilic ionic monomer. The formation of the PSPMAK brush is well proven by 1H NMR, aqueous gel permeation chromatography (GPC), dynamic light scattering (DLS), static light scattering (SLS), atomic force microscopy (AFM), and cryogenic transmission electron microscopy (cryo‐TEM) measurements. Cleavage of the side chains and further analysis reveal that the initiating efficiency of the polymerization is as low as 0.35.
7.
Summary: A unified model is developed for the finite size‐effect on the glass‐transition temperature of polymers, Tg(D), where D denotes the diameter of particles or thickness of films. In terms of this model, Tg depends on both the size and interface conditions. The predicted results are consistent with the experimental evidence for polystyrene (PS) particles and films with different interface situations.
8.
Synthesis and Optical Properties of Sol‐Gel Hybrid Materials that Contain Perfluorocyclobutyl Groups
Kwan‐Soo Lee Jae‐Pil Kim Ho‐Suk Song Won‐Guen Jang Young‐Sik Park Jae‐Suk Lee 《Macromolecular rapid communications》2006,27(16):1330-1334
Summary: A strategy for the synthesis of sol‐gel hybrid materials that contain perfluorocyclobutyl groups is reported. Sol‐gel films have been prepared from three types of siloxane monomers using a typical sol‐gel method in an acidic atmosphere, followed by UV irradiation and dimerization. The materials show high thermal stability that exceeds 400 °C. At a wavelength of 1 550 nm, the refractive index, the birefringence, and the optical loss of the sol‐gel materials are found to be in the ranges of 1.4568–1.4876, −0.0003–0.0029, and 0.34–0.45 dB · cm−1, respectively.
9.
Xi Chen Yang Liu Yingli An Juan Lü Junbo Li Dean Xiong Linqi Shi 《Macromolecular rapid communications》2007,28(12):1350-1355
We report a simple procedure to prepare a novel Au‐micelle composite with a core‐shell‐corona structure. This composite is prepared by reduction of tetrachloroauric acid (HAuCl4 · 3H2O) in dilute aqueous solution containing polystyrene‐block‐poly(4‐vinylpyridine) micelles and poly(ethylene oxide)‐block‐poly(4‐vinylpyridine) copolymers. The micelles with a polystyrene core and a poly(4‐vinylpyridine) shell are transformed into Au‐micelle composites with a polystyrene core, a swollen hybrid Au/poly(4‐vinylpyridine) inner shell, and a poly(ethylene oxide) corona by direct physisorption of gold particles with poly(4‐vinylpyridine) chains.
10.
Monique Roerdink Thomas S. van Zanten Mark A. Hempenius Zhiyuan Zhong Jan Feijen G. Julius Vancso 《Macromolecular rapid communications》2007,28(22):2125-2130
A PFS/PLA block copolymer was studied to probe the effect of strong surface interactions on pattern formation in PFS block copolymer thin films. Successful synthesis of PFS‐b‐PLA was demonstrated. Thin films of these polymers show phase separation to form PFS microdomains in a PLA matrix, and ultrathin films (<5 nm) formed SINPATs on silicon and mica. The SINPATs consisted of strongly surface‐adsorbed PLA blocks on top of which the PFS blocks dewetted into sphere‐like features. The lateral spacing between these features was regular, and was typically much larger than the length scale associated with regular block copolymer phase separation.
11.
Chang‐Chun Wang Qun‐Dong Shen Shao‐Chun Tang Qiang Wu Hui‐Min Bao Chang‐Zheng Yang Xi‐Qun Jiang 《Macromolecular rapid communications》2008,29(9):724-728
To fabricate ferroelectric ultrathin polymer films with large dielectric constants for potential all‐organic electronic devices, ferroelectric polymer nanotubes and a composite of the nanotubes with a dispersed organic semiconductor have been fabricated by template‐assisted methods. The ferroelectricity drops markedly in spin‐coated ultrathin films less than 100 nm thick, whereas P(VDF‐TrFE) nanotubes with a wall thickness of a few ten nm sustain ferroelectricity. The composite nanotubes exhibit a giant dielectric constant as a result of significantly enhanced interface polarization between the nanosized fillers and the polymer matrix. They could be of practical use in supercapacitors, optoelectronic devices, and sensors.
12.
Toshihiko Arita Michael Buback Olaf Janssen Philipp Vana 《Macromolecular rapid communications》2004,25(15):1376-1381
Summary: Application of high pressure, up to 2 500 bar, in cumyl dithiobenzoate‐mediated styrene reversible addition fragmentation chain transfer (RAFT) polymerizations was found to be extremely advantageous with respect to both rate and control of polymerization. The overall rate of polymerization could be increased by a factor of approximately 3 with, e.g., at 23% conversion, concomitantly reducing the polydispersity indices from 1.35 to 1.10. No significant effect of increased pressure on the rate retardation effect was found.
13.
Tingyang Dai Kai Chen Xutang Qing Yun Lu Jinsong Zhu Feng Gao 《Macromolecular rapid communications》2010,31(5):484-489
Polymeric core–shell microstructures have been constructed through a new method, namely sequential precipitation, which is intrinsically a self‐assembly and phase separation process. High‐quality poly(vinyldene fluoride)–polycarbonate–lithium perchlorate composite films with spherical core–shell microstructures have been prepared and determined to consist of conducting cores and insulating shells. Because of the percolation effect, the resulting materials present a dielectric constant as high as 104–107 at the threshold.
14.
Kolattukudy Poulose Santo Andriy Kovalenko Maria Stepanova 《Macromolecular theory and simulations》2010,19(5):228-239
Three‐dimensional mesoscopic morphologies and the thermodynamics of structural phase transitions of amphiphilic lipids at air‐water interfaces are studied using self‐consistent field theory. Changing the relative amount of lipids in the system led to a series of 3D morphologic phases with varying average interfacial area per molecule, mimicking a compression of the model membranes. Membranes of both saturated and unsaturated lipids undergo a transition from cylindrical micelle to lamella when the lipid content in the system increases from 2% to about 19–20%. With further increase in the lipid content, saturated lipids first develop non‐uniform quasi‐2D distributions in the lamella and then gradually transform into a hybrid morphology containing quasi‐planar lamellae. In contrast, unsaturated lipids develop reverse‐micellar morphologies.
15.
Christopher M. Aberg Mohamed A. Seyam Scott A. Lassell Lyudmila M. Bronstein Richard J. Spontak 《Macromolecular rapid communications》2008,29(24):1926-1931
Polymer nanocomposites continue to receive considerable attention as multifunctional hybrid materials, with most nanocomposites fabricated by physical dispersion of surface‐functionalized nanoscale objects. In this study, we explore the viability of growing Pd‐containing nanoparticles from Na2PdCl4 in two different polymers: hypercrosslinked polystyrene (HPS) and an aromatic polyimide (PIm). In HPS, single Pd‐containing nanoparticles possessing a relatively narrow size distribution (ca. 1–4 nm) form upon reduction of the divalent PdCl ions. Single nanoparticles with a broad size distribution ranging from ≈2 to 16 nm develop in PIm, which simultaneously undergoes chemical crosslinking during ion reduction. Such hybrid materials hold promise in molecular catalysis and gas separation.
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Numerical SCFT simulations of inhomogeneous polymers at the mesoscale can easily become computationally extremely demanding as the size (spatial resolution) of the simulated 3D system increases, making massively parallel computing a necessity. A new parallel algorithm for large‐scale 3D SCFT simulations of rod‐coil copolymers with interplay between microphase separation and orientational ordering is presented. For large systems, this algorithm scales well up to 1024 processors, achieving more than 200‐fold speedups. While existing SCFT simulations were limited to studying 1D and 2D models, this algorithm is applied to new, intrinsic 3D structures such as a hexagonally arranged columnar morphology that possesses macroscopic chirality arising as a result of spontaneous symmetry breaking.
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Micro‐Raman spectroscopy has been used to investigate the chemical micro‐heterogeneity of multiphase‐separated poly(ether urethanes) (PETU). Analysis of PETU cross‐sections by means of micro‐Raman spectroscopy revealed the nearly complete absence of soft segments in AI aggregates (called globules). These aggregates are in the order of a few micrometers in size. The composition of the matrix and the AII aggregates (spherulites) was comparable.
18.
Veronica Marin Elisabeth Holder Michael A. R. Meier Richard Hoogenboom Ulrich S. Schubert 《Macromolecular rapid communications》2004,25(7):793-798
Summary: An amino‐functionalized bipyridine ligand was prepared in order to serve as a bridging unit to an activated low‐molecular‐weight monomethyl ether of poly(ethylene glycol) (PEG). Coordination of a ruthenium(II ) phenantroline precursor onto the formed PEG‐containing bipyridine ligand yielded a metal‐containing polymer which shows interesting properties for solar cell applications.
19.
Eun Young Park Jun Woo Kim Dong June Ahn Jong‐Man Kim 《Macromolecular rapid communications》2007,28(2):171-175
A polymer system based on polydiacetylene (PDA) supramolecules that emits red, green, and blue fluorescence has been constructed. The three‐color emitting system is comprised of red‐fluorescent PDA vesicles in which green‐fluorescent fluorescein molecules are encapsulated. Finally, the blue‐fluorescence component is introduced by reacting terminal amine groups on the PDA vesicle surfaces with fluorescamine. Thin PDA‐polymer‐containing poly(vinyl alcohol) films formed by using this strategy display red, green, and blue fluorescence upon excitation with light at specific wavelengths.
20.
Courtney A. Pfluger Rebecca L. Carrier Bing Sun Katherine S. Ziemer Daniel D. Burkey 《Macromolecular rapid communications》2009,30(2):126-132
Plasma Enhanced Chemical Vapor Deposition (PECVD) of poly‐2‐hydroxyethyl methacrylate (pHEMA) biocompatible, biodegradable polymer films were produced alone and cross‐linked with ethylene glycol diacrylate (EGDA). Degree of cross‐linking was controlled via manipulation of the EGDA flow rate, which influenced the amount of swelling and the extent of degradation of the films in an aqueous solution over time. Noncross‐linked pHEMA films swelled 10% more than cross‐linked films after 24 h of incubation in an aqueous environment. Increasing degree of film cross‐linking decreased degradation over time. Thus, PECVD pHEMA films with variable cross‐linking properties enable tuning of gel formation and degradation properties, making these films useful in a variety of biologically significant applications.