•NiCo2O4 nanotubes have been fabricated via a simple technique of electrospinning combined with calcination.•The hierarchical MnO2 nanosheets were grown on NiCo2O4 nanotubes to improve the electrochemical performances.•The NiCo2O4@MnO2 electrode exhibited high rate capability and excellent cycling stability.In this study, hierarchical NiCo2O4@MnO2 composites with ultrathin MnO2 nanosheets uniformly grown on NiCo2O4 nanotubes were prepared by an electrospinning - calcination - hydrothermal method. When tested as an electrode material for supercapacitors, the resulting NiCo2O4@MnO2 composites exhibited the specific capacitance of 706.7 F/g at 3 A/g, high rate capability with a ∼84.9% retention of the initial capacitance and excellent cycling stability (∼136.3% capacitance retention after 10,000 cycles).The NiCo2O4@MnO2 composites were prepared by an electrospinning - calcination - hydrothermal method exhibited high rate capability and excellent cycling stability.

The ordered three-dimensional arrays conjugative polyaniline–graphene composites were fabricated through in-situ chemical oxidative polymerization of aniline in the presence of amino-functionalized graphene sheets (AFG), in which polyaniline (PANI) polymerization is initiated by those amino groups on graphene. Therefore, the resulting PANI nanorod arrays are integrated into a large conjugative frame based on chemical covalent bond incorporation. The structure and properties of these resulting composites were characterized and evaluated by combining Fourier transform infrared spectroscopy, Ultraviolet–visible absorption spectroscopy, Raman spectroscope, X-ray diffraction spectroscopy analyses and electrochemical techniques. Morphology was studied by scanning electron microscopy. It was found that the density and size of ordered PANI nanorod arrays can be manipulated by simply varying the amount of AFG. Such resultant composite exhibits high special capacitance, together with low electrical resistance and excellent cycling stability attributed to conjugative covalent bonds and ordered PANI nanorod arrays. Meanwhile, a new time-dependent heterogeneous nucleation mechanism was proposed and investigated in detail.

Two-photon fluorescent (TPF) Bombyx mori silk fibers were acquired for bioimaging by molecular recognition functionalization. In this context, 2,7-bis((E)-4-((E)-4-nitrostyryl)styryl)-9,9-dioctyl-9H-fluorene (NF) was adopted to functionalize silkworm silk fibers. NF exhibits a large two-photon absorption cross section, but has a low TPF quantum yield in the solid form due to the side-by-side (π–π) molecular stacking. In terms of the molecular recognition between the nitro groups of NF and the amide groups of silk fibroin, the silk fibers acquire the two-photon fluorescent emission with a significant enhancement of 350% in TPF quantum yield of NF molecules, compared with the solid state. For comparison, two other molecules, 2,7-bis((E)-4-methylstyryl)-9,9-dioctyl-9H-fluorene (MF1) and 2,7-bis((E)-4-((E)-4-methylstyryl)styryl)-9,9-dioctyl-9H-fluorene (MF2), were selected for similar experiments. These molecules show little effect due to the lack of molecular recognition. The TPF silk scaffolds were obtained, and high quality imaging of NF in cell culture was finally achieved, which has extremely relevant implications for biomedical applications.

In order to replace terpolymers with bipolymers, three bifunctional comonomers were synthesized to prepare poly(acrylonitrile-co-β-methylhydrogen itaconate) [P(AN-co-MHI)], poly(acrylonitrile-co-3-aminocarbonyl-3-butenoic acid methyl ester) [P(AN-co-ABM)] and poly(acrylonitrile-co-3-ammoniumcarboxylate-3-butenoic acid methyl ester) [P(AN-co  -ACBM)] which can be used as carbon fiber precursor. The stabilization mechanism and effect of comonomer structure on the stabilization of bipolymers were studied by Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and thermogravimetry. Two parameters Es=A1610cm-1/A2244cm-1 and SI=(I0-Is)/I0SI=(I0-Is)/I0 were defined to evaluate the extent of stabilization, and the activation energy (Ea) of the cyclization reactions were calculated by Kissinger method and Ozawa method. The results show that P(AN-co-MHI), P(AN-co-ACBM) and P(AN-co-ABM) exhibit better stabilization than terpolymers containing similar chemical composition, such as lower initiation temperature, larger extent of stabilization and smaller Ea. Furthermore, it is found that 3-ammoniumcarboxylate-3-butenoic acid methyl ester is the most effective one among the three comonomers for improving the stabilization of polyacrylonitrile (PAN) due to the strongest nucleophilicity of COO−NH4+ towards the carbon atom of adjacent nitrile groups. Simultaneously, the rheological analyses show that all the three bipolymers possess better spinnability than PAN homopolymer.

A novel high molecular weight functional polyacetylene bearing oxadiazole group as a pendant, poly{4-[2-(4-octoxyphenyl)-1,3,4-oxadiazolyl]-benzenyloxypropynylene}, was synthesized by [Rh(nbd)Cl]2-Et3N catalyst. The polymer was soluble in common organic solvents such as CHCl3 and THF. The structures and properties of monomer and polymer were characterized and evaluated with FTIR, NMR, UV, TGA, GPC, and CV, respectively. The results show that the polymer possesses high thermal stability and well electron-injection property.

Two-photon fluorescent (TPF) Bombyx mori silk fibers were acquired for bioimaging by molecular recognition functionalization. In this context, 2,7-bis((E)-4-((E)-4-nitrostyryl)styryl)-9,9-dioctyl-9H-fluorene (NF) was adopted to functionalize silkworm silk fibers. NF exhibits a large two-photon absorption cross section, but has a low TPF quantum yield in the solid form due to the side-by-side (π–π) molecular stacking. In terms of the molecular recognition between the nitro groups of NF and the amide groups of silk fibroin, the silk fibers acquire the two-photon fluorescent emission with a significant enhancement of 350% in TPF quantum yield of NF molecules, compared with the solid state. For comparison, two other molecules, 2,7-bis((E)-4-methylstyryl)-9,9-dioctyl-9H-fluorene (MF1) and 2,7-bis((E)-4-((E)-4-methylstyryl)styryl)-9,9-dioctyl-9H-fluorene (MF2), were selected for similar experiments. These molecules show little effect due to the lack of molecular recognition. The TPF silk scaffolds were obtained, and high quality imaging of NF in cell culture was finally achieved, which has extremely relevant implications for biomedical applications.