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To improve the mechanical strength of natural hydrogels and to obtain a sustained drug-delivery device, temperature-/pH-sensitive hydrogel beads composed of calcium alginate (Ca-alginate) and poly(N-isopropylacrylamide) (PNIPAAm) were prepared in the presence of poly(sodium acrylate) (PAANa) with ultrahigh molecular weight (Mη ≥ 1.0 × 107) as a strengthening agent. The influence of PAANa content on the properties, including the beads stability, swelling, and drug-release behaviors, of the hydrogels was evaluated. Scanning electron microscopy and oscillation experiments were used to analyze the structure and mechanical stability of the hydrogel beads, respectively. The results show that stability of the obtained Ca-alginate/PNIPAAm hydrogel beads strengthened by PAANa the alginate/poly(N-isopropyl acrylamide) hydrogel bead (SANBs) was significantly improved compared to that of the beads without PAANa (NANBs) at pH 7.4. The swelling behavior and drug-release capability of the SANBs were markedly dependent on the PAANa content and on the environmental temperature and pH. The bead sample with a higher percentage of PAANa exhibited a lower swelling rate and slower drug release. The drug release profiles from SANBs were further studied in simulated intestinal fluid, and the results demonstrated here suggest that SANBs could serve as a potential candidate for controlled drug delivery in vivo. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

A novel series of triphenylamine-based photorefractive molecules M1–M5 with the different push-pull structures were designed and prepared. These molecules can form stable glasses with low glass transition temperature and their optical absorptions as well as photoconductivities at 633 nm increase systematically with increasing acceptor strength and conjugation length. As an unambiguous evidence, the two-beam-coupling experiment was performed to prove the photorefractive effect in each compound with or without an additional sensitizer. Obvious two-beam-coupling effects were obtained for the molecules with good film-forming ability and long-term stability, and among them single-component M1 which has a highly asymmetric structure using both a nitrobenzene and a cyano group as the acceptor showed the best PR performance with a gain coefficient of 52 cm−1 at 0 V μm−1 and 165 cm−1 at 40 V μm−1. Fast response time of 0.025–0.23 s were also obtained at low electric field for these glasses. The correlation of the molecular structure with the PR property was discussed, and a possible explanation for the unique energy transfer observed in M1 and M2 under zero field was proposed.

Despite being among the most researched energy storage devices, supercapacitors have often suffered from their relatively low operating voltage and energy density, which greatly limit their practical applications. In this work, asymmetric supercapacitors (ASCs) are developed by synergistically designing carbon nanotube composite electrodes with 3D porous structures. The resultant ASC devices exhibit an extended operating voltage of 1.8 V, much higher than that of symmetric supercapacitors (≤1.0 V). Significantly, the obtained ASC devices deliver ultrahigh volumetric energy density as high as 19.8 mWh cm−3 (corresponding to an areal energy density of 198 µWh cm−2), which is the highest value among reported ASC devices. In addition, the ASC devices not only possess outstanding cycling stability and long self‐discharging time, but also exhibit excellent mechanical flexibility under any bending states, even over 5000 bending cycles. The demonstrated flexible ASC devices with high performance are promising to be used as power sources for next‐generation portable and wearable electronics.

trans-Dichlorotetrapyridineruthenium(II) [trans-RuCl2(py)4] was synthesized and the structure was determined by single crystal X-ray crystallography. Highly efficient formation of propylene carbonate (PC) from carbon dioxide and propylene oxide was achieved by using a catalyst system composed of trans-RuCl2(py)4 and hexadecyl trimethyl ammonium bromide under mild conditions (4h, 80 °C, 3.0 MPa). PC was obtained in nearly 100% selectivity without the formation of a polymer. The catalyst could be recycled constantly many times without any significant loss of its catalytic activity. On the basis of the results, a mechanism for the reaction was proposed. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.

Biomineralized polysaccharide alginate membranes with multi-responsive drug release property were prepared via a one-step method. The formation of a biomineralized polysaccharide composition in the membrane was clearly identified through scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS) and Fourier transform infrared spectroscopy (FT-IR). Additionally, the calcium phosphate mineralized component could be found not only in the surface but also in the cross section of the membranes. Drug release behaviours were examined by using indomethacin as a model drug, and the release profiles of the developed membrane were found to be pH-, thermo- and ionic strength-responsive. The drug release of the biomineralized polysaccharide alginate membranes was around 80% within 600 min, while that of the unmineralized ones was almost 100%. These results indicate that the biomineralized polysaccharide component can prevent the permeation of the encapsulated drug and reduce the drug release effectively. The resulting membranes can be used as “smart” polysaccharide material for sustained multi-responsive drug delivery.

The design and synthesis of well-defined polymethylene-b-polystyrene (PM-b-PS, Mn = 1.3 × 104–3.0 × 104 g/mol; Mw/Mn (GPC) = 1.08–1.18) diblock copolymers by the combination of living polymerization of ylides and atom transfer radical polymerization (ATRP) was successfully achieved. The 1H NMR spectrum and GPC traces of PM-b-PS indicated the successful extension of PS segment on the PM macroinitiator. The micellization behavior of such diblock copolymers in tetrahydrofuran were characterized by dynamic light scattering (DLS) and atomic force microscopy (AFM) techniques. The average aggregate sizes of PM-b-PS diblock copolymers with the same length of PM segment in tetrahydrofuran solution (1.0 mg mL−1) increases from 104.2 nm to 167.7 nm when the molecular weight of PS segment increases. The spherical precipitated aggregates of PM-b-PS diblock copolymers with an average diameter of 600 nm were observed by AFM. Honeycomb porous films with the average diameter of 3.0 μm and 6.0 μm, respectively, were successfully fabricated using the solution of PM-b-PS diblock copolymers in carbon disulfide via the breath-figure (BF) method under a static humid condition. The cross-sections of low density polyethylene (LDPE)/polystyrene (PS)/PM-b-PS and LDPE/polycarbonate (PC)/PM-b-PS blends were observed by scanning electron microscope and reveal that the PM-b-PS diblock copolymers are effective compatilizers for LDPE/PS and LDPE/PC blends. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1894–1900, 2010

Polysaccharide-based thermo-responsive material was prepared by grafting PNIPAAm onto hybrid alginate beads, in which a biomineralized polyelectrolyte layer was constructed aiming to enhance the mechanical strength and ensure higher graft efficiency. XPS results demonstrated that the incorporation of PNIPAAm to the hybrid beads was successful, and the PNIPAAm-grafted beads were more hydrophilic than the ungrafted ones as indicated by their swelling behavior. The drug release behaviors revealed that the grafted beads were both thermo- and pH-sensitive, and the PNIPAAm existed in the pores of the alginate beads acted as the “on–off” gates: the pores of the beads were covered by the stretched PNIPAAm to delay the drug release at 25°C and opened to accelerate the drug release at 37°C because of the shrinking of PNIPAAm molecules. This paper would be a useful example of grafting thermo-responsive polymers onto biodegradable natural polymer substrate. The obtained beads provide a new mode of behavior for thermo-responsive “smart” polysaccharide materials, which is highly attractive for targeting drug delivery system and chemical separation. Copyright © 2010 John Wiley & Sons, Ltd.

Two phenothiazine-based conjugated polymers, poly(3, 7-divinylene-N-octyl-phenothiazine-alt-benzo-2,1,3- thiadiazole) (PQS) and poly(3,7-divinylene-N-octyl-phenothiazine-alt-benzo-2,1,3-selenodiazole) (PQSe) were synthesized by Heck coupling reaction. The chemical structures of the two polymers were confirmed by 1H-NMR and Ft-IR. They showed good solubility in some common organic solvents such as tetrahydrofuran (THF), chloroform. The weight-average molecular weight (Mw) of the polymers determined by GPC in THF against polystyrene standards was 3.7 × 103 for PQS and 1.9 × 103 for PQSe, respectively. The temperatures of 5% weight loss (T5) were 385.0°C for PQS and 324.0°C for PQSe, respectively, determined by TGA measurements under nitrogen ambience. UV–vis absorption spectra of the polymer films showed the absorption maxima at 537 nm for PQS and 539 nm for PQSe, with the full width at half maximum (FWHM) of 190 and 230 nm, respectively. The optical band gaps () of the polymer films are 1.86 eV for PQS and 1.80 eV for PQSe, respectively. As the polymers have low-band-gap and broad absorption in the visible region, they may be used as potential light-harvesting materials for photovoltaic devices (PVDs). Furthermore, photoluminescence (PL) spectra of the polymer solutions showed the emission maxima at 698 nm for PQS and 709 nm for PQSe, with FWHM of 152 nm and 167 nm, respectively, which revealed that these two polymers may be used as red and near infrared light-emitting materials for polymeric light-emitting diodes (PLEDs). Copyright © 2009 John Wiley & Sons, Ltd.

An electroluminescent polymer was synthesized by Wittig condensation and characterized by the measurements of 1H-NMR, IR, gel permeation chromatography (GPC), UV–Vis, PL, and cyclic voltammetry (CV). The polymer can be dissolved in common organic solvents such as tetrahydrofuran (THF), chloroform, and dichloromethane. The electroluminescent investigation showed that the non-doped devices with a double-layer configuration (ITO/PEDOT:PSS/Polymer/Mg:Ag) have a stable green emission property. The maximum luminance of the annealed device reaches 2317 cd/m2. The emission maximum and the CIE 1931 coordinate values are respectively stabilized at 552 nm and near (x, y) = (0.43, 0.55) with different voltages. Copyright © 2008 John Wiley & Sons, Ltd.

Novel conjugated polymers containing carbazole, phenothiazine or triphenylamine units in the main chain were designed and synthesized via Wittig, Knovenagel or Heck condensations respectively. A majority of them have good solubility in common organic solvents, high thermal stability and good hole-injection ability. Their diluted solutions in THF showed strong absorption with the absorption maximum in the range of 294∼470 nm and the optic band gaps located in the range of 1.90∼2.75 eV. When irradiated by ultraviolet or visible light, the diluted solutions in THF of the polymers emitted light from purple to yellow color with the emission maximum in the range of 347∼597 nm and the full width at half maximum located in the range of 59∼119 nm. Several polymeric light-emitting diodes (PLEDs) devices were fabricated using these polymers as light-emitting materials, and a double-layer device composed of ITO/PEDOT:PSS/PQTN/Mg:Ag showed a good performance, in which the maximum brightness was measured as 2434.0 cd/m2 under a 11.0 V forward bias voltage. Photovoltaic devices were also investigated using these polymers as an active layer, and a device composed of ITO/PNB/PTCDI-C 13 /Al showed a good performance, which was estimated to have external quantum efficiency at around 1% at 330 nm. From these preliminary experimental results, we may infer that these polymers are good light-emitting materials for PLEDs; while for photovoltaic applications, their absorption spectra need to be further improved to match the solar illumination.

Two series of conjugated polymers with a carbazole moiety were synthesized by Knovenagel and Wittig condensations. The chemical structure, thermogravimetric, photophysical and electrochemical properties of the polymers were characterized by 1H-NMR, IR, GPC, TG, UV-vis, FL, and CV. The results indicated that PBM is the most thermally stable one and PBP is the most thermally instable one. The absorption and emission properties of the polymers were adjusted by the modification of chemical structures. The quenching effect of cyano group and oxygen atom results in the lower fluorescence quantum efficiency. The fitted emission spectra suggested that the emission spectra of all the polymers come from different vibronic transitions and aggregation emission. Copyright © 2008 John Wiley & Sons, Ltd.

A series of amorphous polyphosphazenes containing carbazole-based multifunctional chromophores were synthesized. These polymers show low glass transition temperature (20–65 °C) and can easily be fabricated into optically transparent films with long-term stability. As an unambiguous evidence of photorefractive effect, preliminary two-beam-coupling experiments were performed at 633 nm under room temperature. All of these single-component polymers exhibited photorefractive performance without external electric field or prepoling, and gain coefficient of 91 cm−1 was observed in a polymer with the lowest glass transition temperature. The influence of the alkylene spacer length between the side group and the polymer backbone on the glass transition temperature, chromophore loading, as well as the optical gain was discussed. The steady-state photorefractive performance of a polyphosphazene with the shortest alkylene spacer was enhanced significantly by adding a photoconductive plasticizer N-ethyl-carbazole to lower the glass transition temperature and a gain of 198 cm−1 and a diffraction efficiency of 46% were achieved at zero electric field.

Two hyperstructured photorefractive (PR) molecular glasses (M1 and M2) with a cyclotriphosphazene core are synthesized via nucleophilic substitution and an azo-coupling reaction. These molecules exhibit excellent solubility in common organic solvents and maintain a complete amorphous state in spite of their high glass-transition temperature. The nonlinear optical effects, two-beam coupling and four-wave mixing, respectively, are used to prove the PR performance in the optically transparent films of Ml and M2 doped with 30 % N-ethyl-carbazole. With no external electric field, a gain coefficient of 102 cm -1 and diffraction efficiency of 24 % are obtained in the composite made from Ml, and an even higher gain coefficient of 214 cm -1 and diffraction efficiency of 31 % are obtained in the composite made from M2 owing to its higher chromophore loading.

The crystallization and melting behavior of flame sprayed Polyamide 1010 (PA1010) containing zirconium dioxide (ZrO2) were investigated using differential scanning calorimeter (DSC). ZrO2 has a heterogenous nucleation effect on PA1010, leading to a moderate increase in the crystallization temperature and a decrease in the supercooling temperature. A modified Avrami theory could be successfully used to well describe the early stages of non-isothermal crystallization of PA1010 and its composite coatings. A study of the nucleation activity, which indicated the influence of the filler on the polymer matrix, revealed that the zirconium dioxide nanoparticles had a good nucleation effect on PA1010. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.

Biomineralized polysaccharide-coated alginate beads containing PNIPAAM were prepared. The resulting beads can be used as carriers for sustained pH/temperature-sensitive drug delivery. Characterizations using SEM, EDS, FTIR, and POM revealed that the beads were covered by the calcium-phosphate-mineralized alginate/chitosan membrane. The drug-release behavior was examined using indomethacin as a model drug, and the release profile of the developed materials was found to be responsive to pH and temperature. The release profile could be sustained under neutral conditions, indicating that the mineralized polysaccharide membrane could prevent the permeability of the encapsulated drug and reduce the drug release rate.

A highly efficient catalyst composed of (2,2′-bipy)RuCl 3 (CH 3 OH) and cetyltrimethylammonium chloride is reported for the first time for the formation of propylene carbonate from carbon dioxide and propylene oxide under mild conditions (75 °C, 3.0 MPa). Nearly 100% selectivity and 100% yield of propylene carbonate was achieved. The catalyst can be easily recovered and reused several times without appreciable loss of catalytic activity, total turn over number reaching 2.04 × 10 4 after five catalytic recycles with a turnover frequency higher than 1000 h −1 . A mechanism for the reaction was proposed.

A novel phenothiazine-based polymer was synthesized through the Heck reaction of 3,7-divinyl-N-octyl-phenothiazine with 4,7-dibromo-2-octylbenzotriazole according to the alternating donor-acceptor strategy. The polymer was characterized with 1 H NMR, infrared spectroscopy, gel permeation chromatography, cyclic voltammetry, ultraviolet-visible spectroscopy, and fluorescence spectroscopy. With the polymer used as an active layer, three nondoped polymer light-emitting diodes (PLEDs) with a double-layer configuration were fabricated by the spin-coating approach with different thermal annealing processes. The emission maximum in electroluminescent spectra was stabilized at 616 nm. The maximum luminance reached 2432 cd/m 2 . The coordinate value of Commission International de l'Eclairage 1931 in the double-layer PLEDs after the thermal treatment was nearly stabilized at (x, y) = (0.62, 0.38). Additionally, the luminous efficiency of device II reached a balanceable state with an increase in the current. Therefore, the polymer had an orange-red emission with stable chromaticity coordinates under different driving voltages. Finally, a nondoped device with a stable luminous efficiency and chromaticity was obtained.

Optoelectronic properties from a novel polymer, poly( p -phenylene N -4- n -butylphenyl- N , N -bis-4-vinylenephenylamine) (PNB) have been investigated. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of the material were estimated to be −5.18 and −2.75 eV, respectively, measured with cyclic voltammetry. A single-layer device structure was prepared by spin-coating PNB thin films from a solution on top of an indium–tin oxide (ITO) substrate while aluminum was used as a top electrode. Current density–voltage (J–V) characteristic was measured which showed a typical rectifying behavior. Photovoltaic from a single-layered device was observed under a white arc lamp illumination. This was improved via a double-layer structure comprising vacuum evaporated copper phthalocyanine (CuPc) or N,N ′-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C 13 ) as an additional layer. The open-circuit voltage, short-circuit current and hence the efficiency were improved in the double-layer devices. An ITO/PNB/PTCDI-C 13 /Al device was estimated to have external quantum efficiency (EQE) around 1% at 330 nm. In a comparison of optical absorption and photocurrent spectra, it was demonstrated that the excitons could be separated and further, generated carriers drifting to the opposite electrodes more efficiently in the double-layer cells.

The single layer and multilayer undoped light-emitting devices were fabricated using a new soluble phenothiazine-based derivative, poly(3,7- N -octyl phenothiozinyl terephthalylidene) (POPTP). Through the optimization of device structures, the multilayer device has a maximum luminance of 1203 cd/m 2 at the bias voltage of 9.3 V, using 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) as a hole-blocking layer and tris-(8-hydroxyquinoline)aluminium (Alq 3 ) as a electron-injection/transporting layer. The Commision International de L’Eclairage (CIE) coordinates stabilized at ( x , y ) = (0.46, 0.53) at various bias voltages. Additionally, the dominant wavelength ( λ D ) of around 575 nm and the color purity of approximately 100% indicated a pure yellow emission property. Therefore, POPTP is a stable candidate material with a pure yellow emission for the undoped organic light-emitting diodes (OLEDs).

Polyamide1010 (PA1010) and its composite with nanometer-sized silica (PA1010/n-SiO 2 ) coatings were deposited using a flame spray process. The thermal behaviors, mechanical and tribological properties were investigated. The dry friction and wear behaviors of PA1010 and PA1010/n-SiO 2 composite coatings were systematically investigated under dry sliding conditions against TMK rings by wear-test machine of MRH-3 at room environment. The results showed that the addition of nanometer-sized silica could increase the crystallinity of the coatings, improve the mechanical properties of coatings and reduce friction and wear of pure PA1010 effectively. The worn surfaces were examined using a scanning electron microscope (SEM). The wear mechanism of the coatings was explained in terms of plastic deformation, fatigue tearing and adhesive abrasion. In addition, the nanocomposite coating containing 1.5 wt% nanometer-sized silica displayed better properties.

Two series of copolyimides were designed and synthesized by one-step polycondensation of two diamines, 3,6-diaminoacridine (Acridine) and 4,4′-(9H-fluoren-9-ylidene)bisphenylamine (FBPA), with a dianhydride 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) or 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), respectively. The copolyimides were named as AFFx (Acridine-FBPA-6FDA polyimide) and AFBx (Acridine-FBPA-BTDA polyimide), respectively, where x (x = 0, 1, 3, 5 10, 15 and 20) represents the mole percentage of acridine among the sum of two diamines. Characterization of the polymers was conducted by using FT-IR, EA, GPC, TGA, DSC, UV–vis and FL techniques. The Mw and MWD of AFFx are in the range of 2.29–5.09 × 104 and 1.93–2.72, respectively, as determined using GPC. AFFx could be dissolved in some low boiling point solvents such as THF, CH2Cl2, CHCl3, etc. Thin AFFx films could be prepared by spin coating its CHCl3 or THF solution onto glass. The temperature of 10% weight loss (T10) for the copolyimides was above 540 °C. The emission maximum of AFFx in solution at the excitation wavelength of 480 nm was near 545 nm. And that of AFBx solution at the excitation wavelength of 390 nm was near 525 nm. UV–vis and FL spectra of the copolyimides indicated that the main chromophores in the copolyimides were acridine moieties and the excitation energy transfer from fluorene moieties to acridine moieties could take place. The copolyimides maybe a potential thermostable light-emitting material for organic light-emitting diodes.

Several polymers containing triphenylene moieties in main chain were synthesized by Knovenagel or Wittig condensations. The polymers were characterized by 1 H NMR, IR, GPC, TG, UV–vis, FL and CV. Results indicated that PNB, which was prepared from the polycondensation of 4,4′-dialdehyde-4″- n -butyltriphenylamine with 1,4-bis(triphenylphosphonionmethyl)benzene dibromide, is the most thermally stable one and that PNP, which was prepared from the polycondensation of 4,4′-dialdehyde-4″- n -butyltriphenylamine with p -phenylene diacetonitrile, is the most thermally instable one. The fluorescence quantum efficiency of PNB is 94.3%, which is a high value for optoelectronic polymer materials. All the polymers have a similar CV curve with a reversible oxidation peak and two reduction peaks except that PNB has a single reduction peak.

Polyamide1010 (PA1010) and its composite with nanometer-sized zirconia (PA1010/nano-ZrO2) coatings were deposited using a flame spray process. The kinetics of nonisothermal crystallization of PA1010/nano-ZrO2 composite coatings was investigated by differential scanning calorimetry (DSC) at various cooling rates. Several different analysis methods were used to describe the process of nonisothermal crystallization. The results showed that the modified Avrami equation and Mo's treatment could describe the nonisothermal crystallization of the composite coatings very well. The nano-ZrO2 particles have a remarkable heterogeneous nucleation effect in the PA1010 matrix. The values of halftime and Zc showed that the crystallization rate increased with increasing cooling rates for both PA1010 and PA1010/nano-ZrO2 composite coating, but the crystallization rate of PA1010/nano-ZrO2 composite coating was faster than that of PA1010 at given cooling rate. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

In this work, smart hollow microcapsules made of thermal-/pH-dual sensitive aliphatic poly(urethane-amine) (PUA), sodium poly(styrenesulfonate) (PSS), and Au nanoparticles (AuNPs) for interdependent multi-responsive drug delivery have been constructed by layer-by-layer (LbL) technique. The electrostatic interactions among PUA, PSS, and AuNPs contribute to the successful self-assembly of hollow multilayer microcapsules. Thanks to the shrinkage of PUA above its lower critical solution temperature (LCST) and the interaction variation between PUA and PSS at different pH conditions, hollow microcapsules exhibit distinct pH- and thermal-sensitive properties. Moreover, AuNPs aggregates can effectively convert light to heat upon irradiation with near-infrared (NIR) laser and endow the hollow microcapsules with distinct NIR-responsiveness. More importantly, the NIR-responsive study also demonstrates that the microcapsule morphology and the corresponding NIR-responsive drug release are strongly dependent on the pH value and temperature of the media. The results indicate that the prepared hollow PUA/PSS/Au microcapsules have the great potential to be used as a novel smart drug carrier for the remotely controllable drug delivery. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43008.

A novel carbazole–triphenylamine copolymer-bearing pendant bipyridine PM1TPA and corresponding europium (III) complexed polymer PM1TPA–Eu–x, in which the values of x are 0.1, 0.5, and 1.0 representing the molar ratio of bipyridine ligands complexed with Eu(III), were designed and synthesized. Their chemical structures were confirmed by 1H NMR, FT-IR, and elemental analysis. Both PM1TPA and PM1TPA–Eu shows good solubility in common organic solvents such as tetrahydrofuran (THF) and CHCl3. The 5% weight loss temperature (Td5%) of PM1TPA and PM1TPA–Eu–1.0 are 363oC and 306oC, respectively. The photoluminescence (PL) spectra of PM1TPA–Eu in solution consists of two emission bands, one in the 400–570 nm region and another at 612 nm, corresponding to the emission of polymer main chain and europium complexes, respectively. When the concentration of PM1TPA–Eu–1.0 in THF solution increases, the PL intensity in the 400–570 nm regions became more and more weaker. And only the characteristic emission of europium complex was observed in the solid film, which indicates that the excited energy absorbed by the polymer backbone was efficiently transferred to the europium complexes. Furthermore, nearly monochromatic red electroluminescence from europium complex was observed from the polymeric light-emitting diode using PM1TPA–Eu–1.0 as the emissive layer under 25 V forward bias. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42746.

Graphitic carbon nitride (g-C3N4) nanosheets with large aspect ratios were fabricated from bulk g-C3N4 through an efficient top-down approach of moderate disintegration-exfoliation using diluted H2SO4 as an "efficient knife". By prior disintegration in a diluted H2SO4 solution, the exfoliation of bulk g-C3N4 was effectively accelerated. The as-prepared g-C3N4 nanosheets possess a two-dimensional (2D) thin-layer structure with seven-atom thickness, a large lateral size of about 1 μm, and a high specific surface area of 80 m(2) g(-1). Compared with the bulk precursor, the g-C3N4 nanosheets showed much higher efficiency of photogenerated charge transfer and separation, and consequently exhibited enhanced photocatalytic activity toward hydrogen evolution and pollutant decomposition under both full-sunlight and visible-light irradiation.

A carbazole-based photorefractive polyphosphazene was prepared via post-azo-coupling reaction. The polymer shows a low glass transition temperature of 50 °C, and has an excellent solubility in common organic solvents, which can easily be fabricated into an optically transparent film with long-term stability. The nonlinear optical effects, including two-beam-coupling and four-wave-mixing, were studied at 633 nm under room temperature. A gain coefficient of 79 cm −1 and a diffraction efficiency of 18% were observed at zero external electric field without any added plasticizer or sensitizer.

Two novel polymers PQP(poly(3, 7-N-octyl phenothiozinyl cyanoterephthalylidene)) and PQM (poly(3, 7-N-octyl phenothiozinyl cyanoisophthalylidene)) containing phenothiazine were synthesized for application in red and orange light-emitting diodes. The synthesized polymers were characterized using UV-visible, photoluminescence and electroluminescence (EL) spectroscopy. The single-layer EL devices of indium tin oxide(ITO)/PQP(or PQM)/Mg : Ag and multi-layer devices of ITO/PQP(or PQM): N, N'-diphenyl-N, N'-bis(3-methylphenyl) -[1, 1'-biphenyl]-4, 4' -diamine(TPD) (44 nm)/2, 9-dimethyl-4, 7-diphenyl -1, 10-phenanthroline (BCP, 5 nm)/tris(8-hydroxyquinolinato) aluminium(AlQ3, 20 nm)/Mg : Ag were fabricated. The EL spectra from the devices based on PQP peaked at the wavelength of 664 nm and covered red and infrared regions. The maximal brightness was measured to be about 60 cd m−2 at the applied voltage of 17 V. The devices based on PQM gave bright orange light-emission peaking at 608 nm and the maximal luminance was 150 cd m−2 at the applied voltage of 14 V.

A carbazole compound was synthesized by Knovenagel condensation and characterized by the measurements of 1 H NMR, IR and melting point. A multilayer organic light-emitting diode (OLED) using this compound as an active layer was fabricated by vacuum-deposition. This OLED showed a turn-on voltage of approximately 4.5 V and a maximum luminance of 910 cd/m 2 . Additionally, the maximum luminous efficiency was found as 0.95 cd/A, at this point the device luminance was measured as 146 cd/m 2 at an operating voltage of 7 V. The coordinate value of CIE 1931 was calculated as ( x , y ) = (0.3843, 0.5345) from the electroluminescence (EL) spectrum, which suggested that the device can emit a yellow-green light.

A quaternary copolyimide containing perylene, fluorene and oxadiazole units in the backbone, named as OPFF x , was designed and synthesized by a one-step polycondensation under high temperature. The successful polymerization was proved by both elemental analysis and FT-IR spectra. Weight average molecular weight of the polymer was in the range of 2.02–3.09 × 10 4 as measured by GPC. OPFF x with low oxadiazole content has good solubility in common organic solvents such as chloroform and tetrahydrofuran. Thin film of OPFF x could be prepared by directly spin-coating of its chloroform solution onto quartz glass. The polymer showed high thermal stability and the temperature of 10% weight loss was higher than 494 °C as measured by TGA in nitrogen, and no apparent glass transition temperature was observed from DSC measurement in nitrogen up to 350 °C. The film of OPFF x irradiated by ultraviolet light emitted strong reddish-orange fluorescence. Cyclic voltammetry measurement indicated that OPFF x could be easily reduced ( n -doped). Thus, the polymer may potentially be used as a thermal stable light-emitting and electron transporting material for light-emitting diodes.

Several conjugated polymers containing phenothiazine moieties in the main chain were synthesized by Knovenagel or Wittig condensations. The polymers were identified and characterized by 1H-NMR, IR, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), UV-vis and fluorescent (FL) spectra. Results indicated that the m-polymer, which was prepared from the polycondensation of N-octyl-3,7-diformylphenothiazine with m-phenylene diacetonitrile, is the most thermally stable one in all the polymers synthesized. While, the p-polymer, which was prepared from the polycondensation of N-octyl-3,7-diformylphenothiazine with p-phenylene diacetonitrile, is the most thermally instable one. The introduction of a cyano group made the absorption and emissive maxima red-shift from 429 and 537 nm for the Ph-polymer to 465 and 597 nm for the p-polymer respectively. The quinoid structure formation allows the p-polymer to have a lower band gap than any other polymers. Emissive spectra of all these polymers in tetrahydrofuran (THF) solution have a narrow half-peak width. Copyright © 2006 John Wiley & Sons, Ltd.

The formation of a cylinder-like helical conformation induced by solvation was observed from a conjugated polymer poly(N-octylcarbazole ethylene). The polymer was synthesized by McMurry condensation using N-octyl-3,6-diformylcarbazole as monomer, in which the alkylcarbazolyl group was functioned as a turn angle. IR analysis indicated that the double bond in the polymer chain mainly takes a cis- conformation. Computer simulation revealed that the polymer could form into a hollow tubular nano-structure with a cavity of less than 1 nm in diameter by folding its strand. The helical conformation formed by solvent induction was further proved by the measurements of circular dichroism (CD) spectrum, specific rotatory power and fluorescent (FL) spectra. Copyright © 2006 John Wiley & Sons, Ltd.

Two series of novel ternary copolyimides containing perylene and fluorene units in the backbone were synthesized by one-step polycondensation of diamine (4,4′-(9H-fluoren-9-ylidene)bisphenylamine, FBPA) with perylene dianhydride (3,4,9,10-perylenetetracarboxylic dianhydride, PTCDA) and a comonomer [4,4′-(hexafluoroisopropylidene) diphthalic anhydride, 6FDA or 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, BDTA]. The polymers were named as PFFx (PTCDA-FBPA-6FDA) and PFBx (PTCDA-FBPA-BTDA), respectively, and their chemical structures were identified by FT-IR spectra and elemental analyses. Perylene contents in the copolyimides were determined through a quantitative UV-vis spectroscopy method, which are in agreement with the values calculated from the added raw materials both for PFFx and PFBx. Gel permeation chromatography (GPC) measurement suggested that the weight average molecular weight (Mw) is in the range 2.1–5.09 × 104 and the molecular weight distribution (MWD) is 1.86–2.72 for PFFx, and those for PFBx are 2.64–4.73 × 104 and 2.44–2.92, respectively. Thermogravimetric analysis (TGA) measurements showed that the copolyimides are very thermally stable with a temperature of 10% weight loss (T10) in the range 546–563°C for PFFx, and 538–548°C for PFBx. The copolyimides also have good solubility in common organic solvents such as chloroform and tetrahydrofuran. These unique properties can be attributed to the existence of the bulky diphenylfluorene moieties in the polymer backbone. All the copolyimides can emit strong fluorescence both in solution and in films, which make them possibly be used as thermostable light-emitting materials for organic light-emitting diodes. Copyright © 2006 John Wiley & Sons, Ltd.

A series of monolithic photorefractive molecules forming organic glasses with low glass transition temperature (−2–69 °C) was synthesized starting from 9-(2-ethyl-hexyl)-carbazole. These molecules show distinct photoconductivity due to the carbazole moiety and obvious optical nonlinearity owing to the push–pull structure. Some of these molecules can form transparent films with good stability and excellent optical quality. The absorption of the molecules is more or less red-shifted depending on the strength of the donor–acceptor internal charge transfer. A molecule with a highly asymmetric structure using both a nitrobenzene and a cyano group as the electron-withdrawing components (M2) shows the best photorefractive performance, its gain coefficient was measured as high as 266 cm −1 at an applied electric field of 42 V/μm without any extra sensitizer while the FWM efficiency was measured to be 5% at electric fields of 27 V/μm.

A series of liquid crystalline copolyesters, possibly having auxetic behaviour, were designed and synthesized by solution polycondensation from 4,4′-(decanoxy) dibenzoyl chloride with 2,5-bis(p-alkoxy benzoyloxy) hydroquinone and 4,4′-dihydroxy-α,ω-diphenoxydecane in different ratios. All the polymers have lower melting point ranging from 80 to 140 °C, which is beneficial to the liquid crystalline state formation and the thermoplastic processing. The lateral rods derived from 2,5-bis(p-alkoxy benzoyloxy) hydroquinone monomer gave an obvious influence on properties of the resulting polymers, in which the liquid crystalline state stability and the solubility in common organic solvents were enhanced. Observations from POM and DSC indicated that all the polymers are thermotropic liquid crystalline with nematic characteristics.

Carbazole-based polymers bearing methine groups with low glass transition temperature ( T g ) for photorefractive purpose were prepared via postfunctionalization strategy. The successful reaction was identified by spectroscopic analysis and gel permeation chromatography. This approach is more facile compared with the direct polymerization from corresponding functional monomer. Chromophore content of the resulting polymers varied from 25% to 63% depending on the type of chromophore as calculated from 1 H NMR spectra. Molecular weight of the polymers are higher than 2.4 × 10 5 , and the polymers are easily soluble in common organic solvents like DMF and THF. T g of the polymers ranges from 40 to 58 °C depending on the structure of chromophore, and the polymers are relatively stable under 310 °C.

In this study, a novel nylon with long alkane segments (also called nylon 1313), which was synthesized using 1,13-tridecanedioic acid in our laboratory, has been characterized. Different rheological behaviors of nylon 1313 have been presented using steady shear, creep recovery, and dynamic tests. The time-temperature effects have also been investigated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1643–1651, 2005

Carbazole-based bi-functional photorefractive polymers with controlled azo group content were prepared via a post-azo-coupling reaction. The polymers were characterized by IR, 1 H NMR, UV–visible, DSC and GPC. Both IR and 1 H NMR results proved that the azo group was attached to the polymer. As shown by UV–visible spectrum measurement, the azobenzene chromophore contents increased with extending the post-azo-coupling reaction time, and changed from 14% to 67% when the reaction time extended from 6 to 60 h. Molecular weight ( M w ) of the polymers can reach 2.5×10 4 as measured by GPC, which is much larger than the polymers with similar structure prepared by direct polymerization from the corresponding functionalized macromonomers. Glass transition temperature ( T g ) of the polymers increased with the azobenzene chromophore contents.

A grafted nylon-6 membrane that can be used in alkaline storage batteries was prepared by grafting acrylic acid onto nylon-6 film using (NH4)2Ce(NO3)6/H2SO4 as initiator. The nylon-6 films to be grafted were pre-swelled in 20% formic acid solution, activated with an aqueous solution containing ceric ammonium nitrate and sulfuric acid. The grafting efficiency was greatly affected by the reaction temperature, the concentration of (NH4)2Ce(NO3)6/H2SO4, and the swelling time in formic acid. The degree of grafting that could be achieved under optimized conditions was up to 312%. Through infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) analysis, it was realized that graft reaction took place on the nitrogen atom of the amide group and the density of grafting point increased with an increase in the degree of grafting in a certain range. The highest density of grafting point was found to be 51.3% in a given set of reaction conditions. X-ray diffraction illustrated that the crystallinity of the grafted membranes decreases with the increase of the degree of grafting. A membrane with 173% degree of grafting showed electric resistance of 0.11 Ω/cm2, and ion exchange capacity (IEC) of 8.7 mmol/g, which can meet the requirement for the electric discharge of storage batteries with strong power. Copyright © 2004 John Wiley & Sons, Ltd.

This paper describes the synthesis and physical study of several new photorefractive (PR) polymers, which are composed of a new type of nonlinear optical (NLO) chromophore attached onto conjugated poly(p-phenylene-thiophene)s. Since the NLO chromophore is labile in many reaction conditions, the Stille coupling reaction was used to prepare these polymers. The resulting polymers exhibit high PR performances. An optical gain coefficient of 158 cm -1 at a field of 50 V/μm and a diffraction efficiency of 68% at a field of 46 V/μm for polymer P1 were obtained, which are among the best values for fully functionalized PR polymers to date.

Isothermal crystallization, subsequent melting behavior and non-isothermal crystallization of nylon 1212 samples have been investigated in the temperature range of 160–171 °C using a differential scanning calorimeter (DSC). Subsequent DSC scans of isothermally crystallized samples exhibited three melting endotherms. The commonly used Avrami equation and that modified by Jeziorny were used, respectively, to fit the primary stage of isothermal and non-isothermal crystallizations of nylon 1212. The Avrami exponent n was evaluated, and was found to be in the range of 1.56–2.03 for isothermal crystallization, and of 2.38–3.05 for non-isothermal crystallization. The activation energies (ΔE) were determined to be 284.5 KJ/mol and 102.63 KJ/mol, respectively, for the isothermal and non-isothermal crystallization processes by the Arrhenius' and the Kissinger's methods.

Copolymers, poly(4-vinylpyridine- co -acrylic acid) (PVPA), with different composition were synthesized, and their palladium complexes were prepared. The catalytic properties of the palladium complex for the hydrogenation of aromatic nitro compounds were investigated. The palladium complex of PVPA can form a homogeneous system in ethanol. The optimum catalytic activity for hydrogenation of nitrobenzene was obtained when the molar content of 4-vinylpyridine (VPy) units in PVPA was 57.5% and VPy/Pd molar ratio was 6. The presence of 0.1 mol/l KOH can promote the catalytic activity to a great extent. In most cases, the hydrogenation of aromatic nitro compounds yields the corresponding aniline compounds almost quantitatively. The catalyst shows especially good activity for the hydrogenation of nitrophenols and nitroanisoles. The catalytic stability was also examined.

DNA–polyaniline (PAn) complex Langmuir–Blodgett film modified glassy carbon electrode (GCE) was used as a new voltammetric sensor (DNA/PAn-LB/GCE) for xanthine (XA) detection. The characteristic of DNA/PAn-LB film was studied by electrochemical impedance spectroscopy and scanning electron microscope. Electrochemical behaviors of XA at the sensor were studied in pH 7.0 phosphate buffer solutions by cyclic voltammetry and differential pulse anodic voltammetry. The results showed that this new modified electrode exhibited an excellent immunity from uric acid and hypoxanthine interference and a new sensitive and selective electroanalytical method for XA was proposed with wider linear range. Under the optimum conditions, the calibration curve for XA was obtained over the range of 7.0×10 −8 –1.0×10 −5 mol L −1 , with the detection limit of 3.0×10 −8 mol L −1 . The practicability of this method was demonstrated by determining the concentration of XA in human serum samples.

In continuation of our endeavor to develop and characterize the high performance polypropylene composites and their toughening master batches (TMBs), we report here the melt rheological properties of toughened polypropylene with balanced rigidity (TRPP). The relations of shear stress (τ), shear rate , apparent viscosity (ηa), temperature (T) and compositions of TRPPs were systematically investigated. Experimental data revealed that under ordinary shear flow conditions, the TRPP melts showed a pseudo-plastic feature. Based on the complexity of the melt flow of the blended poly-component/multiphase polymer system and together with our experimental and related literature results, the relationship between ηa and T for blended polymer melts was recommended to be expressed by the equation: log ηa = α0 + α1/T, where α1 was defined as the temperature coefficient of apparent viscosity. The relationship between τ and can be expressed by the equation: , and the exponent n is decreased as τ increasing. At a given τ or , the ηa of TRPPs decreased with ethylene-propylene to styrene-butadiene elastomer ratios from 20/80 to 100/0, increased with total elastomer content in TRPP and decreased with elastomer amount in TMB increasing. The manner of changes in ηa with compositions were not affected by the τ or T. Copyright © 2001 John Wiley & Sons, Ltd.

The excellent synergistic effect of physical/mechanical properties of polyurethane/epoxy (PU/EP) interpenetrating polymer network (IPN) and the validity of nanofilling have one potential to improve the wear resistance of polymeric materials. With the aim of practical application, PU/EP IPN nanocomposites are prepared with nanodiamond (ND) as a reinforcing additive. Results showed the uniform thermal stability and the excellent compatibility between PU and EP in ND-hybridized PU/EP IPN. Simultaneously, ND particles work as crosslinked points improving the physical/mechanical properties of ND-hybridized PU/EP IPN, especially the wear resistance. The measurement of tribological property and the scanning electron microscope indicated that the wear resistance is able to be improved a lot by the formation of IPN and by the addition of ND. Consequently, the tribological mechanism of PU/EP IPN nanocomposites comes into being. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40244.

Poly(4-vinylpyridine-co-N-vinylpyrrolidone)(VPy-co-NVP) and its palladium complex (VPy–NVP–Pd) were prepared. The palladium complex was used as catalyst for the hydrogenation of some nitroaromatics. The molar content of VPy units in VPy-co-NVP was determined as 31.25% by 1H NMR. VPy–NVP–Pd can be easily resolved in ethanol forming a homogeneous catalytic hydrogenation system together with substrates. The optimum catalytic activity for hydrogenation of nitrobenzene appeared when VPy/Pd molar ratio was 2. The catalytic behavior of the catalyst was found to be greatly affected by the type and concentration of added alkalies. The highest hydrogenation rate for nitrobenzene was found in a 0.1 mol/l ethanol solution of potassium hydroxide. The catalytic stability was examined by using nitrobenzene and 4-nitroanisole as substrates.