Self Organization and Redox Behavior of Poly(vinylferrocene)-block-Poly(isobutylene)-block-Poly(vinylferrocene) Triblock Copolymer †

Self organization and redox behavior of a ferrocene containing triblock copolymer, poly(vinylferrocene)-block-poly(isobutylene)-block-poly(vinylferrocene), with narrow molecular weight distribution in solutions and in thin films were investigated. Dynamic light scattering studies of the block copolymer in dilute solutions indicated that the polymer chains aggregated at relatively low concentrations. The aggregations of polymer chains were observed in toluene, as well as in tetrahydrofuran at concentrations as low as 0.014 mg/mL and 0.0045 mg/mL, respectively. Thin films of the copolymer showed reversible single electron redox behavior, similar to that of ferrocene. Morphology and micro-phase separation of the copolymer was analyzed by transmission electron microscopy.     

Fabrication of Gold Nano‐Structures with Azopolymer Templates

Fabrication of gold nano‐patterns has been demonstrated employing surface relief structures created on films of an azobenzene‐functionalized polymer as templates. The surface relief templates were photoinscribed on the azopolymer films in one‐step with two laser beams. Thin layers of gold were over‐coated on the polymer templates by thermal evaporation. Gold lines of a few hundred nanometer width were successfully fabricated by pyrolyzing the azobenzene polymer. Sub‐micron gold dots were also created. The resulting gold structures exhibited the same periodicity as the polymer templates.     

DFT study on the intermolecular interactions between Aun (n = 2–4) and thymine

Density functional B3LYP method with 6-31++G** basis set is applied to optimize the geometries of the luteolin, water and luteolin–(H₂O)_n complexes. The vibrational frequencies are also studied at the same level to analyze these complexes. We obtained four steady luteolin–H₂O, nine steady luteolin–(H₂O)₂ and ten steady luteolin–(H₂O)₃, respectively. Theories of atoms in molecules (AIM) and natural bond orbital (NBO) are used to investigate the hydrogen bonds involved in all the systems. The interaction energies of all the complexes corrected by basis set superposition error, are within −13.7 to −82.5 kJ/mol. The strong hydrogen bonding mainly contribute to the interaction energies, Natural bond orbital analysis is performed to reveal the origin of the interaction. All calculations also indicate that there are strong hydrogen bonding interactions in luteolin–(H₂O)_n complexes. The OH stretching modes of complexes are red-shifted relative to those of the monomer.     

Photosensitized Solid-state Polymerization of Diacetylenes in Nanoporous TiO2 Structures

In situ topochemical polymerization of two diacetylene monomers within nanoporous TiO₂ thin films was carried out under visible light irradiation. One of the monomers used contains a carboxylic acid group, which could help to link the monomer onto the TiO₂ surface covalently. UV-Vis absorption and Raman studies showed that both monomers were successfully photopolymerized. These results suggest that the covalent linkage of the diacetylene to the nanoparticle through the carboxylic acid group is not needed. Since photopolymerization of diacetylene is typically induced by excitation of the monomer at λ< 300 nm, the observed red shift of the photopolymerization wavelength is attributed to the photosensitization effect of TiO₂. The morphological study of the polydiacetylene/TiO₂ nanocomposite revealed that the diacetylene monomers were polymerized in the vicinity of the TiO₂ nanoparticles. This is attributed to the fact that the electron-transfer process occurs at the interface of nanocrystalline TiO₂ (nc-TiO₂) and the diacetylene monomer and the polymerization is expected to be initiated near the nc-TiO₂ surface. Photopolymerization of the carboxylated diacetylene monomer with other oxides nanoparticles, such as ZnO and SiO₂ was also investigated.     

Fabrication of TiO2 Grating with Composites of Azobenzene Polymer and TiO2 Nanoparticles

We have used the formation of surface relief gratings (SRG) on azobenzene polymers to manipulate TiO₂ nanoparticles and to fabricate TiO₂ nanoparticle gratings. Suspensions of an azobenzene polymer (PDO3) and TiO₂ were used to spin coat thin films on glass slide substrates. By interfering coherent light from an Argon laser on the surface of the PDO3‐TiO₂ composite films, SRGs were fabricated. Atomic force microscopic images of the SRGs show TiO₂ nanoparticles dispersed throughout the sample, and in particular, at the peaks of the SRG after oxygen plasma treatment. The lateral forces acting on the azobenzene polymer during the SRG fabrication drag the TiO₂ nanoparticles. These results indicated that it is feasible to create TiO₂ nanoparticle gratings with the composites.     

Nanocomposites of TiO 2 and Siloxane Copolymers as Environmentally Safe Flame-Retardant Materials †

Composites of titanium dioxide (TiO₂) nanoparticles and biocatalytically synthesized dimethylsiloxane copolyamides were prepared, and their thermal and flame-retardant properties were investigated. The flammability properties such as heat release capacity and total heat release were measured from microscale cumbustion calorimetry (MCC). The thermal degradation temperatures, char yields, and the heat-release capacities of these nanocomposites were significantly improved over the pure polymers. The heat-release capacities of the siloxane copolymer nanocomposites with 20wt% of TiO₂ were found to be 167 and 129 J/g K, which is a 35% less than the pure polymers (260 and 194 J/g K, respectively). The SEM/EDAX surface-analysis studies on nanocomposite films and their char revealed that nanocrystalline-TiO₂ plays an important role in forming carbonaceous silicate char on the surface as a protective layer.     

Fabrication of Dye-sensitized Solar Cells and Fluorescence Quenching Study Using Thiophene Based Copolymers

Photovoltaic performance of dye sensitized solar cells fabricated with a commercially available thiophene based copolymer was investigated. Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(bithiophene)], a highly soluble polythiophene, was used as a sensitizer. An open-circuit voltage of 0.64 V and a short-circuit current density of 0.36 mA/cm² were measured. The incident photon to current conversion efficiency for the polymer was measured. Fluorescence from the other polythiophene, poly(3,3′-didodecyl quarter thiophene) was found to be quenched when blended with phenyl C₆₁ butyric acid methyl ester (PCBM) (1:1 wt ratio), indicating the charge transfer from the conjugated polymer to PCBM.     

副翼铰链力矩脱机校准试验的简化方法及验证

飞机副翼铰链力矩飞行实测是新机定型的必要环节。采取传统的脱机载荷校准方法完成某新型民机副翼铰链力矩的校准试验需要自主研发专用实验台,难度大、成本高。本文提出了一种简化的副翼作动器脱机载荷校准试验方法,不需要研制专用实验台,仅使用一台拉压试验机,排空作动器中的液压油,将作动器直接安装在拉压试验机上进行拉压试验即可完成校准试验,建立载荷模型。通过两点和四点地面联机验证试验验证了载荷模型的正确性,其中四点加载时左右副翼载荷模型的误差分别为0.8%和0.3%。该方法为具有类似结构飞机活动面的脱机载荷校准试验提供了一种重要的技术途径。