On polyhydroxybutyrate banded spherulites, concentric rings were observed between cross polarizers or without polarizers. The rings used to be considered as cracks. In this paper, we provide evidences to distinguish t...On polyhydroxybutyrate banded spherulites, concentric rings were observed between cross polarizers or without polarizers. The rings used to be considered as cracks. In this paper, we provide evidences to distinguish the concentric rings from cracks observed on PHB spherulites. Furthermore, atomic force microscopy confirmed that these concentric rings with varying spacing were growth terraces rather than cracks. The height of the terraces reached up to several hundred nanometers. It was observed that the external terraces were higher than the internal terraces, which was proposed to result from layer by layer growth. This is the first report on the new microscopic feature of polyhydroxybutyrate spherulites. Spherulites with birefringent bands, wavy fluctuation of height were also observed.展开更多
A novel polyelectrolyte PNANT functionalized with electron donor-acceptor type azobenzene chromophores has been synthesized through post-polymerization azo coupling reaction and characterized by 1H-NMR,FTIR and UV-Vis...A novel polyelectrolyte PNANT functionalized with electron donor-acceptor type azobenzene chromophores has been synthesized through post-polymerization azo coupling reaction and characterized by 1H-NMR,FTIR and UV-Vis spectroscopy.The degree of functionalization (DF) of PNANT was 20% measured by elemental analysis.The degree of polymerization and its distribution were determined by GPC to be X n=251 with a polydispersion index 1.53.A glass transition temperature of 119℃ was observed from DSC thermogram. H-aggregation of azo chromophores of PNANT in spin-coated film and self-assembled film were detected from UV-Vis spectra,and the degree of H-aggregation of PNANT in the self-assembled film was found to be higher than that in the spin-coated film.Dichroism was optically induced in the spin-coated film and self-assembled film upon the irradiation of a polarized Ar + laser beam at 488 nm.The orientational order parameter obtained was 0.15 for spin-coated film and 0.07 for the self-assembled film.The resulting dichroism detected by UV-Vis spectra exhibited long-term stability.展开更多
Crylic acid and azobenzene containing acrylate copolymers PEAPH were fabricated into multilayers with their counterpart polyelectrolyte(poly(diallyldimethylammonium) chloride)(PDAC) in N,N′-dimethylformamide(DMF) usi...Crylic acid and azobenzene containing acrylate copolymers PEAPH were fabricated into multilayers with their counterpart polyelectrolyte(poly(diallyldimethylammonium) chloride)(PDAC) in N,N′-dimethylformamide(DMF) using the layer-by-layer electrostatic adsorption technique.The self-assembly of water soluble and insoluble PEAPH in DMF was studied and compared.FTIR was used to detect the ionization of carboxyl acid of PEAPH during the assembling processes.All results show that both the water-soluble and water-insoluble PEAPH can be deposited with PDAC based on the electrostatic attraction instead of other interactions.In assembling processes PEAPH molecules are deposited in molecular level instead of molecular aggregation and form a cross-linking multilayer structure.Assembling media of DMF and water do not have obvious influence on the multilayer structure.展开更多
Photovoltaic properties of blend composites, composed of N,N′ didodecy1 3,4,9,10 perylene biscarboximide (PDI) and a soluble conductive polymer poly(3 hexylthiophene) (PHT), are reported. PDI can form the interpenetr...Photovoltaic properties of blend composites, composed of N,N′ didodecy1 3,4,9,10 perylene biscarboximide (PDI) and a soluble conductive polymer poly(3 hexylthiophene) (PHT), are reported. PDI can form the interpenetrating network structure with PHT chains, as evidenced in the UV Vis spectrum. The investigation of the photoluminescence (PL) spectra revealed that PL of PHT was quenched when it was blended with PDI. The photovoltaic devices using PHT as both the sensitizer and hole conductor, and PDI films as the electron conductor were prepared to estimate the photovoltaic performance of the blend films. An improvement of conversion efficiency in the blending cells compared with that of the pure PHT cells was observed. Spectral properties and current voltage( I\|V) characteristics of the PHT/PDI composite films showed that the perylene diimide dopant can improve the photovoltaic performance of PHT films significantly through the increase of visible light absorption, exciton dissociation, diffusion and transportation.展开更多
文摘On polyhydroxybutyrate banded spherulites, concentric rings were observed between cross polarizers or without polarizers. The rings used to be considered as cracks. In this paper, we provide evidences to distinguish the concentric rings from cracks observed on PHB spherulites. Furthermore, atomic force microscopy confirmed that these concentric rings with varying spacing were growth terraces rather than cracks. The height of the terraces reached up to several hundred nanometers. It was observed that the external terraces were higher than the internal terraces, which was proposed to result from layer by layer growth. This is the first report on the new microscopic feature of polyhydroxybutyrate spherulites. Spherulites with birefringent bands, wavy fluctuation of height were also observed.
文摘A novel polyelectrolyte PNANT functionalized with electron donor-acceptor type azobenzene chromophores has been synthesized through post-polymerization azo coupling reaction and characterized by 1H-NMR,FTIR and UV-Vis spectroscopy.The degree of functionalization (DF) of PNANT was 20% measured by elemental analysis.The degree of polymerization and its distribution were determined by GPC to be X n=251 with a polydispersion index 1.53.A glass transition temperature of 119℃ was observed from DSC thermogram. H-aggregation of azo chromophores of PNANT in spin-coated film and self-assembled film were detected from UV-Vis spectra,and the degree of H-aggregation of PNANT in the self-assembled film was found to be higher than that in the spin-coated film.Dichroism was optically induced in the spin-coated film and self-assembled film upon the irradiation of a polarized Ar + laser beam at 488 nm.The orientational order parameter obtained was 0.15 for spin-coated film and 0.07 for the self-assembled film.The resulting dichroism detected by UV-Vis spectra exhibited long-term stability.
文摘Crylic acid and azobenzene containing acrylate copolymers PEAPH were fabricated into multilayers with their counterpart polyelectrolyte(poly(diallyldimethylammonium) chloride)(PDAC) in N,N′-dimethylformamide(DMF) using the layer-by-layer electrostatic adsorption technique.The self-assembly of water soluble and insoluble PEAPH in DMF was studied and compared.FTIR was used to detect the ionization of carboxyl acid of PEAPH during the assembling processes.All results show that both the water-soluble and water-insoluble PEAPH can be deposited with PDAC based on the electrostatic attraction instead of other interactions.In assembling processes PEAPH molecules are deposited in molecular level instead of molecular aggregation and form a cross-linking multilayer structure.Assembling media of DMF and water do not have obvious influence on the multilayer structure.
文摘Photovoltaic properties of blend composites, composed of N,N′ didodecy1 3,4,9,10 perylene biscarboximide (PDI) and a soluble conductive polymer poly(3 hexylthiophene) (PHT), are reported. PDI can form the interpenetrating network structure with PHT chains, as evidenced in the UV Vis spectrum. The investigation of the photoluminescence (PL) spectra revealed that PL of PHT was quenched when it was blended with PDI. The photovoltaic devices using PHT as both the sensitizer and hole conductor, and PDI films as the electron conductor were prepared to estimate the photovoltaic performance of the blend films. An improvement of conversion efficiency in the blending cells compared with that of the pure PHT cells was observed. Spectral properties and current voltage( I\|V) characteristics of the PHT/PDI composite films showed that the perylene diimide dopant can improve the photovoltaic performance of PHT films significantly through the increase of visible light absorption, exciton dissociation, diffusion and transportation.
