In an effort to favor the formation of straight polymer chains without crystalline grain boundaries, we have synthesized an amphiphilic conjugated polyelectrolyte, poly(fluorene-alt-thiophene) (PFT), which self-assembles in aqueous solutions to form cylindrical micelles. In contrast to many diblock copolymer assemblies, the semiconducting backbone runs parallel, not perpendicular, to the long axis of the cylindrical micelle. Solution-phase micelle formation is observed by X-ray and visible light scattering. The micelles can be cast as thin films, and the cylindrical morphology is preserved in the solid state. The effects of self-assembly are also observed through spectral shifts in optical absorption and photoluminescence. Solutions of higher-molecular-weight PFT micelles form gel networks at sufficiently high aqueous concentrations. Rheological characterization of the PFT gels reveals solid-like behavior and strain hardening below the yield point, properties similar to those found in entangled gels formed from surfactant-based micelles. Finally, electrical measurements on diode test structures indicate that, despite a complete lack of crystallinity in these self-assembled polymers, they effectively conduct electricity.

The direct electrochemical copolymerization of pyrrole (Py) and epsilon-caprolactone at various monomer ratios was carried out by potentiostatic methods in nitromethane. Characterizations of the novel copolymer were based on scanning electron microscopy, differential scanning calorimetry, thermal gravimetrical analysis, cyclic voltammetry, electrochemical impedance spectroscopy, Fourier transform infrared spectra, and elemental analysis studies. The results showed that the electrochemical oxidation of Py and epsilon-caprolactone comonomers generated true copolymers rather than blends of the two homopolymers. The electrical conductivity of the copolymers increased with the amount of polypyrrole in the copolymer between the value of 8.2 S/cm and 0.6 S/cm. A probable mechanism of copolymerization was proposed. (C) 2009 Wiley Periodicals, Inc. J AppI Polym Sci 112: 1070-1075, 2009

Polymer solar cells generally contain a low bandgap p-type conjugated polymer as photosensitizer and an inorganic or organic n-type semiconductor as electron acceptor. We investigated two nanostructured composites of the complementary semiconductors: nanometer-scale blends and interpenetrating nanorod arrays. In the blend approach, new low bandgap polymers were synthesized to match with electron-acceptors such as C(60)-PCBM and C(70)-PCBM for increased absorption efficiency. The nanorod arrays were fabricated by solution-based electrochemical growth. Photovoltaic performance of the composites is also discussed.

The effect of side-chains on the molecular weight and the optical and electrical property of a low band gap copolymer poly{(9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-decyloxythien-2-yl)-2,1,3-benzothiadiazole]-5',5"-diyl} (PF-co-DTB) was studied. The decyloxy side-chains help to increase molecular weight (Mw = 115,000) and decrease the band gap (1.78 eV) as well as the oxidation potential (-5.4 eV). Zero-field mobility of 2×10-5 cm2/Vs is measured in hole-only devices. Photovoltaic devices based on PF-co-DTB/fullerene bulk-heterojunction show power conversion efficiency of up to 1.6% under air mass 1.5G, 100 mW/cm2 illumination. Side-chains effect on the photovoltaic devices studies show the trade-off between short circuit current increase and open-circuit voltage drop. Thermal annealing on device performance is also discussed.

Efficient polymer solar cells based on a low band gap copolymer poly{(9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-decyloxythien-2-yl)-2,1,3-benzothiadiazole]-5′,5″-diyl} and (6,6)-phenyl-C71-butyric acid methyl ester (C70-PCBM) were demonstrated with 2.4% power conversion efficiency under air mass 1.5G, 100mW∕cm2 illumination. The broad absorption peak of C70-PCBM in 440–530nm complements the absorption valley (regions between two absorption peaks at 416 and 584nm) of the polymer. The external quantum efficiency measurement further demonstrates that this increased absorption contributes significantly to the generation of photocurrent. Morphology studies on the blend films indicated that excellent miscibility between polymer and C70-PCBM favors exciton separation. The linear relationship between light intensity and short circuit current density shows efficient and balanced charge transport resulting in increased photocurrent and fill factor.

Low band gap conjugated polymers with proper energy levels for charge transfer are required to achieve high-efficiency polymer solar cells. We report the synthesis and characterization of two new regioregular copolymers that are based on 3-alkoxythiophene monomers: poly(3-octylthiophene-2,5-diyl-co-3-decyloxythiophene-2,5-diyl) (POT-co-DOT) and poly{(9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-decyloxythien-2-yl)-2,1,3-benzothiadiazole]-5',5' '-diyl} (PF-co-DTB). Compared to the alkyl substituents, the alkoxy side chains on the thiophene units can effectively lower the band gap of copolymers and enhance the charge transfer to electron acceptors such as (6,6)-phenyl C61-butyric acid methyl ester (PCBM). The chemical structure and regioregularity of the copolymers were confirmed by NMR. Both copolymers are readily soluble in organic solvents and form high-quality thin films. Electrochemical and photophysical studies reveal band gaps of 1.64 eV for POT-co-DOT and 1.78 eV for PF-co-DTB. Bulk heterojunction photovoltaic devices were fabricated using blends of these copolymers with PCBM as the active layer, ITO-glass as the anode, and aluminum as the cathode. Power conversion efficiency of 1.6% was obtained under simulated solar light AM 1.5 G (100 mW/cm2) from a solar cell with an active layer containing 20 wt % PF-co-DTB and 80 wt % PCBM. Regioregular poly(3-decyloxythiophene-2,5-diyl) (P3DOT) was also studied for comparison purposes.

Based on eligibility a fuzzy CMAC controller (FCE) is proposed. The structure of FCE system is presented, and its learning algorithm is deduced. To make the algorithm fit to on-line control, an efficient implementation of FCE method is also given. Applying the FCE controller in a ship steering control system, the simulation results show that the ship course can be properly controlled in case of the disturbances of wave, wind, current. It is demonstrated that the proposed algorithm is a promising alternative to conventional autopilots.

Poly(aryleneethynylene)s(PAEs) can be used in polymer light-emitting devices (PLED) and photovoltaic cells due to their relatively high efficient energy transfer and luminescence. The emission color of PAEs can be turned by incorporating narrow band-gap comonomers into the PAEs' backbone. A new class of poly(aryleneethynylene)s containing an aryl heterocyclic structure was prepared by Pd-catalyzed cross couplings between 4,7-dibromo-2,1,3-benzothiadiazole(BT)and 2,7-diet-hynylene-9,9-dioctylfluorene(PFE)with different feed radio of PFE to BT, using Pd(PPh_3)_4 and CuI as catalysts in the presence of triethylamine and toluene. In the case of Pd-catalyzed cross couplings, each individual narrow-band-gap unit is separated from both sides by wide-band-gap segments when the narrow-band-gap component is under or equal to 50% in the copolymer. The narrow-band-gap units function as exciton traps allow efficient intramolecular energy transfer from wide-band-gap segments to narrow-band-gap unit. All these polymers had a number-average (molecular) mass, M_n, about 4 000~12 000 and showed good solubility in chloroform and toluene. The actual molar ratios of PFE to BT in the copolymers were estimated by means of elemental analysis. The results indicate that the actual ratio of PEF to BT in the copolymer is very close to the feed ratio. The absorption and photoluminescent spectra of the copolymers were studied. The maximal emissions of PL and UV spectra slightly red-shifted with gradual increase of BT's content. The result indicates that when the polymer contains alternating narrow band-gap aromatic units BT and large band-gap units PFE the tendency is to form a π-stacked structure which will be enhanced due to intermolecular charge transfer (CT) between polymer molecules. So that we could tune the emission color of polymers through attaching different ratio of narrow band-gap comonomer.

A copolymer of pyrrole and propylene oxide was synthesized by an electrochemical method. The product was confirmed to be a copolymer by electrochemical and spectral experiments. The influences of the electrode materials and solvents on the copolymerization were explored. A probable mechanism was proposed. (C) 2003 Wiley Periodicals, Inc.

The conducting property of four kinds of I-2-doped polydienes, including cis-1,4-polybutadiene (cis-PBD), trans-1,4- polybutadiene (trans-PBD), cis-1,4-polyisoprene (cis-PIP) and trans-1,4-polyisoprene (trans-PIP) has been studied. The influences of microstructure, molecular weight and temperature on the conductivity of I-2-doped polydiene also were reported. Moreover, electrochemical properties of I-2-doped polydiene were investigated on the first time with cyclic voltammetry and complex impedance measurement. The studies of cyclic voltammetry indicate that these materials have good electrochemical activity. With the technology of impedance measurement, charge transfer resistance (R-cl), double layer capacitance (C-dl) and general impedance behavior of, I-2-doped polydiene were also discussed.

High trans-l,4-polybutadiene ( −96% (trans)) was prepared by lanthanum naphthenate catalytic system. The conductivity of obtained polybutadiene doped with iodine reaches about −100 s/cm, which is 2 orders of magnitude higher than the value reported.4,5 During the I2-doping, the conjugated sequence was formed through double bond shifting reaction. According to the relationship between conductivity and temperature, conducting mechanism of doped high trans-l,4-polybutadiene is fit on variable range hoping (VRH) model.

High trans-polybutadiene (over 96% trans 1,4- content) was prepared by lanthanum naphthenate, dibutyl magnesium and THF catalytic system. The dependence of polymerization on molar ratio of catalyst components (Mg/La,Mg/THF), different rare earth elements,solvents and temperature was studied in detail. It was found that the dependence of polymerization rate on monomer concentration followed the 1(st) order relationship.