Showing papers by "Wang Zhang Yuan published in 2009"
TL;DR: Poly(N-isopropylacrylamide) was labelled using a fluorogen with an aggregation-induced emission feature by direct polymerization to serve as a fluorogenic probe that reveals fine details in the thermal transitions in the aqueous solution of the polymer.
143 citations
TL;DR: In this article, an aggregation-induced emission enhancement (AIEE) effect was observed in the case of tetraphenylethene (TPE) units 1 and 2, where the TPE-functionalized luminogens are nonemissive in dilute solutions but luminescent as solid aggregates, showing a novel behavior of aggregationinduced emission.
Abstract: Phenylacetylene and 1-pentyne derivatives containing aminated tetraphenylethene (TPE) units 1 and 2 are synthesized. The TPE-functionalized luminogens are nonemissive in dilute solutions but luminescent as solid aggregates, showing a novel behavior of aggregation-induced emission (AIE). The monomers are polymerized to their corresponding polymers P1 and P2 with an E conformation by organorhodium catalysts, although Rh-catalyzed polymerizations normally yield Z-rich polyacetylenes. Whereas P1 fluoresces faintly in THF, its light emission is enhanced by aggregation in aqueous media, exhibiting an aggregation-induced emission enhancement (AIEE) effect. On the other hand, P2 is AIE active: the emission of its nanoaggregates suspended in 90% aqueous mixture is ∼57-fold stronger than that of its solution in THF. A novel superamplification effect is observed in the emission quenching of P2 nanoaggregates by picric acid (PA): the quenching constant (KSV) is nonlinearly increased with the quencher concentration an...
123 citations
TL;DR: In this paper, a series of highly polar phenylacetylene derivatives with active hydrogen atoms have been directly polymerized to polyelectrolyte P1−P5 using organorhodium complexes.
Abstract: Acetylenic monomers containing highly polar functional groups, especially those with active hydrogen atoms, have been difficult to polymerize because their toxic interactions with transition metal complexes deactivate catalyst systems. In this work, we succeeded in direct polymerizations of a series of highly polar phenylacetylene derivatives. The polymerizations of 4-ethynylbenzoic acid (1), 4-hydroxybutyl 4-ethynylbenzoate (2), 6-(4-ethynylphenoxy)hexanoic acid (3), 4-ethynylaniline (4), and 1-ethynyl-4-nitrobenzene (5) catalyzed by organorhodium complexes afforded corresponding polymers (P1−P5) of high molecular weight (Mw as high as 488 500) and low polydispersity index (Mw/Mn as low as 1.03). The structures of the polymers were characterized spectroscopically. Treatments by base and acid readily transformed neutral polymers P1 and P4 to polyelectrolytes P1− and P4+, respectively. Simple mixing of the conjugated polyelectrolytes with multiwalled carbon nanotubes (MWNTs) afforded polyacetylene/MWNT nan...
38 citations
TL;DR: In this paper, a fluorescence "turn-on" method was proposed to detect the critical micelle concentration (CMC) of surfactants, and the results were consistent with the data obtained by the classical techniques.
Abstract: We report a fluorescence “turn-on” method to detect the critical micelle concentration (CMC) of surfactants. This method works well for both cationic and anionic surfactants. It employs an unprecedented mechanism (aggregation-induced emission, or AIE) to determine the CMC values, and the results are consistent with the data obtained by the classical techniques. In addition, this method renders the convenient detection of the CMC values. Any large and professional instruments are unnecessary, instead, a portable UV lamp and an ultrasonic generator are enough to carry out the detection in an ordinary laboratory. Considering that micelles are interesting entities and have found applications in many important fields such as emulsion polymerization, template of nanosized materials synthesis, controllable drug delivery and macromolecular self-assembling. Our experimental results may offer a facile, sensitive and promising method to detect the formation of micelles constructed by the new amphiphilic molecules and macromolecules.
34 citations
TL;DR: In this paper, a hybrid of phenylacetylene derivatives with multiwalled carbon nanotubes (MWNTs) was prepared by simply mixing the two components in common organic solvents such as dichloromethane.
Abstract: Phenylacetylene derivatives containing carbazole (1) and fluorene (2) moieties were polymerized by [Rh(nbd)Cl]2 into corresponding polymers P1 and P2 of high molecular weights (Mw ∼ 150 × 103–465 × 103) in high yields (up to 98%). The polymers were characterized by NMR, IR, UV, PL, and CV techniques. Hybrids of the polymers with multiwalled carbon nanotubes (MWNTs) were prepared by simply mixing the two components in common organic solvents such as dichloromethane. The solvating power of the polymer carrying the electron-donating carbazolyl pendant (P1) is stronger than that of its counterpart carrying fluorenyl pendant (P2), due to the stronger donor–acceptor (D–A) interaction between the P1 chains and the MWNT walls. This work clearly manifests that D–A effect plays an important role in the polymer-aided MWNT dispersion in organic solvents. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4995–5005, 2009
32 citations
TL;DR: In this paper, multifunctional polyacetylenes and their nanohybridges with liquid crystallinity, light emission, and electrical conductivity were developed for short (s)- and long (l)-multiwalled carbon nanotubes (MWNTs).
Abstract: Multifunctional polyacetylenes and their nanohybrids with liquid crystallinity, light emission, and electrical conductivity are developed in this work. New acetylene monomers containing biphenyl mesogens and polynuclear chromophores, namely 4-[3-(1-pyrenyl)propylcarbonyloxy]-4′-biphenylyl 11-(4-ethynylphenoxy)undecanoate (1), 4-[3-(1-pyrenyl)propylcarbonyloxy]-4′-biphenylyl 10-undecynoate (2), and (9-fluorenyl)methyl-4-[(9-decynyl)-carbonyloxy]-4′-biphenylyloxycarbonylmethyl carbamate (3), were synthesized and transformed to their corresponding polymers (P1−P3) by the polymerization reactions catalyzed by organorhodium complexes of Rh+(nbd)[C6H5B−(C6H5)3] and [Rh(diene)Cl]2. Whereas none of the monomers were mesomorphic, P1 and P2 were liquid crystalline. The pyrene pendants enabled P1 and P2 to function as dispersants for short (s)- and long (l)-multiwalled carbon nanotubes (MWNTs). P1 assisted the dissolution of s- and l-MWNTs in THF, with respective solubilities as high as 723 and 625 mg/L. The resulta...
31 citations
TL;DR: In this paper, a new fluorescence technique for monitoring layer-by-layer self-assembling processes of polycations and polyanions is developed, which is a fluorogenic dye named 1,1-bis[p-(diethylaminomethyl)phenyl]-2,3,4,5-tetraphenylsilole (A2HPS).
18 citations
TL;DR: In this article, a multilayer EL device with a configuration of ITO/Polymer:PVK/BCP/Alq3/LiF/Al is constructed, which emit blue lights of ∼487 nm.
Abstract: Poly(1-phenyl-1-octyne)s containing different stereogenic and chromophoric pendants {-[(C6H13)C= C(C6H4-p-CO2-R)]
n
-R = [(1S)-endo]-(−)-borneyl (P3), (1R,2S,5R)-(−)-menthyl (P4), -C6H4-p-(1R,2S,5R)-(−)-menthyl (P5), 2-napthyl (P6), 4-biphenylyl (P7)} have been designed and synthesized. The polymers are prepared in moderate yields by WCl6-Ph4Sn and possess high molecular weights (M
w up to 64000). The structures and properties of the polymers are characterized and evaluated by NMR, TGA, UV, CD, PL, and EL analyses. All the polymers are thermally stable and their temperatures for 5% weight loss locate in the range of 300 to 416°C under nitrogen. The energy band gaps of all the polymers are ∼3.0 eV. Polymers P4 and P5 show CD absorptions associated with the helicity of the polymer segments. Excitation of the THF solutions of P3–P7 by UV irradiation gives strong blue lights of ∼485 nm with quantum yields higher than 20%. The thin films of the polymers also emit in the same spectral region, indicative of little aggregation-caused quenching of light emission. Multilayer EL devices with a configuration of ITO/Polymer:PVK/BCP/Alq3/LiF/Al are constructed, which emit blue lights of ∼487 nm. The maximum luminance and external quantum efficiency vary with the pendant groups, with P6 exhibiting the highest external quantum efficiency of 0.16%. The spectra stability of the EL devices is outstanding and the EL peak maximum experiences little change with the applied voltage.
4 citations
TL;DR: In this paper, it was shown that polymer nanowires respond to external perturbations and undergo transfiguration upon exposure to the irradiation of high-flux electron beams.
Abstract: Polymer nanowires were found to respond to external perturbations and to undergo transfiguration upon exposure to the irradiation of high-flux electron beams. The phenomenon is general, observable in the nanowires of conjugated and nonconjugated polymers with linear and hyperbranched structures. The transfiguration ceased to occur after the nanowires had been annealed at temperatures higher than the glass transition temperatures of the polymers. The phenomenon is rationalized to be associated with the residual internal stress in the nanowires that is relieved through the electron-beam irradiation and/or thermal annealing. This work thus offers cautionary advice that a proper annealing treatment should be exercised, if one wishes to fabricate polymer nanostructures and miniature devices with reliable stability and durable performance.
2 citations
Posted Content•
1 citations
TL;DR: In this article, the composites of multiwalled carbon nanotubes (MWNTs) and different disubstituted polyacetylenes, and the polymer chains wrapped onto the MWNTs via π-π interactions, were demonstrated.
Abstract: Disubstituted polyacetylenes are fluorescent polymers,and they are more stable than their monosubstituted counterparts.In comparison with the reports about those monosubstituted polyacetylenes,there is only one example showing the dispersing effects of disubstituted polycetylenes on carbon nanotubes.In this letter we demonstrated the fabrication of the composites of multiwalled carbon nanotubes(MWNTs) and different disubstituted polyacetylenes,and the polymer chains wrapped onto the MWNTs via π-π interactions,leading to the improved solubility of MWNTs in organic solvents.This methodology is scatheless to MWNTs.Meanwhile,the disubstituted polyacetylenes encapsulating the MWNTs exhibited their unique photoluminescence properties.
TL;DR: In this article, a thiol-functionalized poly(phenylacetylene) and multiwalled carbon nanotubes (MWNTs) were synthesized and characterized.
Abstract: A thiol-functionalized poly(phenylacetylene) has been synthesized and characterized.The disappearance of the characteristic vibrations at 3312 and 776 cm-1(CCH)and 2106 cm-1 (CC),together with the vanishing of the chemical shifts at 3.0(CCH) and the appearance of the chemical shifts at 6.4 (CC—H) indicate the polymerization of the thiol-containing monomer.The hybrid of thiol-functionalized poly-(phenylacetylene) and multiwalled carbon nanotubes(MWNTs) showed good solubility in organic solvents.Meanwhile,the wrapping of the polymer chains on MWNTs led to the surface functionalization.By aid of the interactions between thiol groups and zinc cations,ZnO nanoparticles were assembled onto out-shells of the hybrids.These results suggested a novel route to the fabrication of multi-component nanostructures.
Journal Article•
TL;DR: In this article, a phenylacetylene monomer bearing a dendron moiety was carried out by using a rhodium complex Rh[(nbd)Cl_2]_2 as catalyst.
Abstract: Polymerization of a phenylacetylene monomer bearing a dendron moiety was carried out by using a rhodium complex Rh[(nbd)Cl_2]_2 as catalyst.The structure of the resultant was characterized with infrared(IR),nuclear magnetic resonance(NMR),and UV-Visible absorption spectroscopic techniques;the experimental data confirmed the generation of the expected polyphenylacetylene derivative(P1) with dendron pendants.P1 was soluble in common organic solvents such as chloroform,N,N-dimethylformamide oxide,and tetrahydrofurran(THF),and its average molecular weight was about 57300.The steric repulsion of between the bulky dendritic side chains make the polymer main-chain take a stereoregular cis-cisoid conformation.Consequently,P1 exhibits a pronounced shoulder at around 440 nm in the absorption spectrum its THF solution.Meanwhile,the bulky dendrons around the polymer main-chain protect the main-chain from thermal-induced decomposition via the "jacket effect",thus P1 lost 5% of its weight at a temperature of 295℃,which is about 70℃ higher than its parent polymer,or polyphenylacetylene.