Synthesis and characterization of soluble, blue-fluorescent polyamides and polyimides containing substituted p-terphenyl as well as long aliphatic segments in the main chain

A novel class of semiflexible polyamides and polyimides bearing substituted p-terphenyl as well as long aliphatic segments in the main chain were synthesized through pyrylium salts. Characterization of polymers was accomplished by inherent viscosity, elemental analysis, FT-IR, NMR, UV-vis luminescence spectroscopy, X-ray analysis, differential scanning calorimetry, thermomechanical analysis, thermogravimetric analysis, isothermal gravimetric analysis, and water uptake measurements. Polyamides displayed a degree of crystallinity and dissolved in polar aprotic solvents containing lithium chloride, as well as in trichloroacetic acid. Polyimides were amorphous and showed an excellent solubility, being soluble in various common solvents. The solutions of polyamides in DMF were blue-fluorescent with maxima at 362-370 nm. The emission maxims were not influenced appreciably upon the structure of the pendent groups and the length of the aliphatic spacers of backbone. The polymers possessed T(g)s at 98-131 degrees C and exhibited a satisfactory thermal stability. (C) 1999 John Wiley & Sons, Inc

Rigid-rod polyamides and polyimides derived from 4,3 ''-diamino-2 ',6 '-diphenyl- or di(4-biphenylyl)-p-terphenyl and 4-amino-4 ''-carboxy-2 ',6 '-diphenyl-p-terphenyl

4,3 "-Diamino-2',6'-diphenyl- or di(4-biphenylyl)p-terphenyl (3a or 3b) and 4-amino-4 "-carboxy-2',6'-diphenyl-p-terphenyl (6) were synthesized through pyrylium salts and used for the preparation of rigid-rod polyamides and polyimides. The polymers were characterized by inherent viscosity, elemental analysis, FT-IR, H-1-NMR, C-13-NMR, W-vis, X-ray, differential scanning calorimetry (DSC)? thermomechanical analysis (TMA), thermal gravimetric analysis (TGA) isothermal gravimetric analysis, and moisture absorption. They were amorphous. All polyamides as well as the polyimide derived from 3b and benzophenonetetracarboxylic dianhydride dissolved in polar aprotic solvents and H2SO4 98%. Polyamide prepared from 6 showed blue fluorescence in dimethylformamide solution. The T(g)s, of polyamides ranged from 235 to 285 degrees C. The polymers possessed excellent thermooxidative stability with no weight loss up to 379-417 degrees C in air

Synthesis and photovoltaic properties of novel alternating phenylenevinylene or fluorenevinylene copolymers containing perylene bisimide

Two novel alternating phenylenevinylene copolymers P6 and P12 as well as one fluorenevinylene copolymer F connected at the 1,7 bay positions with perylene bisimide were synthesized by Heck coupling. They were characterized by GPC, FT-IR, 1H NMR, TGA, TMA, UV-vis, cyclic voltammetry and photoluminescence (PL) emission spectra. The copolymers were soluble in common organic solvents and thermally stable up to ∼300 °C. Their glass transition temperatures were 48-60 °C. The long wavelength absorption maximum was located at 510-542 nm with optical band gaps of ∼2.0 eV. The PL emission maximum of P6 and P12 was red-shifted relative to F. The photovoltaic performance of P6, P12 and F was also investigated. © 2010 Elsevier Ltd. All rights reserved.link_to_subscribed_fulltex

Alternating phenylenevinylene and thienylenevinylene copolymers with cyano groups: Synthesis, photophysics and photovoltaics

Two alternating conjugated copolymers TTP and TTT were synthesized by Heck coupling of 2,3-bis-(5-bromothiophene-2-yl)acrylonitrile with 1,4-dihexyloxy-2,5-divinylbenzene and 3-hexyl-2,5-divinylthiophene, respectively. The absorption spectra of the copolymers in THF solution showed three maxima around 270, 370 and 460 nm with optical band gaps of 2.30-2.34 eV. The electrochemically estimated band gaps of copolymers were 2.04-2.10 eV. The thin film absorption spectra were broad and extended about from 250 to 600 nm with a long wavelength maximum near 470 nm. The copolymers emitted yellow-orange light with maximum at 528-551 nm in THF solution and 567-610 nm in thin film. TTP showed the most red shifted emission maximum between the copolymers. The performance of the photovoltaic cells which were fabricated using blends of the copolymers with 6,6-phenyl C61-butyric acid methyl ester (PCBM) (1:1 and 1:4, w/w) as well as pure copolymers was investigated. © 2008.link_to_subscribed_fulltex