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A facile and bottom-up approach has been presented to prepare 2D Ni-MOFs based on cyanide-bridged hybrid coordination polymers. After thermally induced sulfurization and selenization processes, Ni-MOFs were successfully converted into NiS and NiSe2 nanoplates with carbon coating due to the decomposition of its organic parts. When evaluated as anodes of Li-ion batteries (LIBs) and Na-ion batteries (NIBs), NiS and NiSe2 nanoplates show high specific capacities, excellent rate capabilities, and stable cycling stability. The NiS plates show good Li storage properties, while NiSe2 plates show good Na storage properties as anode materials. The study of the diffusivity of Li(+) in NiS and Na(+) in NiSe2 shows consistent results with their Li/Na storage properties. The 2D MOFs-derived NiS and NiSe2 nanoplates reported in this work explore a new approach for the large-scale synthesis of 2D metal sulfides or selenides with potential applications for advanced energy storage.

Polyaniline with a leaf-like hierarchical structure of 3 μm in length, 2 μm in width, 100 nm in thickness and crisscrossed nanofibers decorated on the surface, was successfully prepared in one step polymerization of aniline in the presence of sodium heptafluorobutyrate. The synthesized polyaniline shows superhydrophobicity with a water contact angle of 151° due to the combination of the low surface tension of fluorinated chain and the rough micro/nanostructure. Chemical structure and composition of the resultant PANI were characterized by FTIR, UV–vis, XRD and XPS. The formation mechanism of the hierarchical structure was investigated by monitoring the morphology development with the polymerization time. This method is facile and applicable for the large scale fabrication. Many potential applications can be expected based on the superhydrophobic PANI micro/nanostructures.

A facile method was successfully developed for the preparation of a hierarchical nanocomposite of vertical polyaniline (PANI) nanorods aligned on the surface of functional multiwalled carbon nanotubes (FMWNTs) by in situ polymerization of PANI on the surface of FMWNTs. The formation mechanism was illustrated according to the morphological evolution of PANI-FMWNTs nanocomposite at different polymerization times. The hierarchical nanocomposite possessed higher special capacitance and better stability than each individual component as supercapacitor electrode materials due to the synergistic effect of both components, as well as to the special hierarchical structure, which not only increases the specific surface area of the nanocomposite but also facilitates the penetration of electrolyte ions. This research gives a better insight into the preparation of functional hybrid nanocomposites by combining different dimensional nanomaterials.

In this article, a new catalyst carrier kapok–polyacrylonitrile (PAN) composite microtube was fabricated based on the natural kapok fiber. Kapok-PAN core–shell composite microtubes were prepared by a cetyltrimethylammonium bromide (CTAB) assisted self-assembly method. The formation mechanism was proposed and the influence of the concentration of acrylonitrile (AN) monomer and CTAB on the morphology of kapok–PAN was investigated. The hydrophilicity and specific surface area of kapok microtubes were improved because of the outside PAN coating constructed by the PAN nanoparticles aggregation. Gold nanoparticles (Au NPs) were immobilized on the surface of kapok–PAN microtubes via in situ reduction of chloroauric acid (HAuCl 4 ) by sodium borohydride (NaBH 4 ). The obtained Au NPs with mean diameter of 3.1 nm were well dispersed without any aggregation. In addition, kapok–PAN–Au composites exhibited excellent catalytic activity and could be recovered easily without apparent decrease of activity, as demonstrated via the reduction of 4-nitrophenol to 4-aminophenol by NaBH 4 . The kapok–PAN composite microtubes may be one of the promising supporting materials in developing low-cost, high-efficiency catalyst carriers for metal NPs.

Flower-like polyaniline–polyvinyl alcohol (PANI/PVA) multidimensional architectures assembled from 2D petals were successfully synthesized in the dilute solution of PVA by the oxidation polymerization. PANI/PVA flowers have a diameter of about 2.5 μm and consist of many interlaced sheet petals. Chemical structure and composition of polymerized PANI/PVA were characterized by Fourier transform infrared (FTIR) spectroscopy, Ultraviolet and visible spectroscopy (UV–vis), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). In order to research the formation mechanism of the 3D flower-like PANI/PVA, their growth process was followed by measuring the morphological evolutions of products with the different polymerization times. The results showed that the flower-like PANI/PVA originated from sheet petals, which then self-assembled into flower-like microstructures. In addition, the effect of PVA concentration on the morphology of the 3D flower-like PANI/PVA was also investigated.

A novel 2D leaf-like polyaniline with special hierarchical micro/nanostructures, a length of about 3 μm, width of about 2.3 μm and thickness of about 120 nm, has been successfully synthesized in the presence of poly (acrylic acid-co-maleic acid) sodium salt (PAA/MA-SS), which is self-assembled from 2D square nanoplate and 1D nanorods. Its surface consists of highly cross-linked nanorods of approximately 100 nm in length and 30 nm in diameter. In order to investigate the formation mechanism of such 2D leaf-like polyaniline, some micro/nanostructures of polyaniline are synthesized at different polymerization times and the results show that the polyaniline microleaves originate from square nanoplates, which then self-assemble into leaf-like micro/nanostructures with nanorods on the surface.

Liquid droplets atop both isotropically and anisotropically patterned substrate surfaces are investigated experimentally. The patterns are realized by means of elastic wrinkling/buckling of a thin layer of gold coated atop polystyrene shape memory polymer. Static contact angles are measured, and images showing the shapes of droplets are captured. The results obtained from isotropically patterned substrates suggest that surface roughness has no apparent effect on the static contact angles in this study. However, atop anisotropically patterned substrates, both the static contact angles and shapes of droplets vary with the direction of wrinkles and size of droplets.

In the present numerical study, we introduce a finite element analysis for heterogeneous materials via a random distribution of materials to predict effective elastic properties. With this random distributing strategy, a large scale parametric analysis via finite element becomes feasible for the multi-phase heterogeneous solids. Taking a well-documented tungsten–silver bi-continuous material as an example, the numerical prediction provided here for the effective properties is checked by experimental testing data available in open publication. Discussions on the present finite element prediction and other approaches are also made by comparing with Hashin and Shtrikman (J Mech Phys Solids 11:127–140, 1963) bounds in the composite mechanics.

A micro-scale analytical model for predicting size-dependent microhardness is presented. The indentation size effect is explained by dissipation energy associated with the contact surfaces. Micro-mechanics mechanism of this energy dissipation is studied via a plastic deformation analysis of micro-scale asperities on the contact surface under indentation. The analysis shows that the microhardness depends not only on the properties of the bulk material under test, but also the properties of the contact surface, such as the plastic behavior of the micro-asperities on contact surfaces. The dependence of microhardness on the roughness parameters of the contact surfaces is also revealed from the analysis.

Leaf-like hierarchical polyaniline (PANI) structure with interlaced nanofibers on the surface was prepared by chemical oxidation polymerization of aniline assisted by sodium dodecyl benzene sulfonate (SDBS). The chemical structure and the composition of the leaf-like PANI obtained were characterized by FTIR, UV–vis, XRD and XPS. In order to investigate the formation mechanism of such micro/nanostructures, some micro/nanostructures of PANI polymerized at different polymerization times were synthesized and observed for comparison. The results show that the PANI micro/nanostructures originate from PANI microleaves due to SDBS as soft template, which then covered with interlaced nanofibers on the surface. The leaf-like PANI micro/nanostructures exhibit good hydrophobic property with a water contact angle of 134.3° resulted from the hydrophobic long dodecyl groups of SDBS dopant.

Uniform sized Co9 S8 /MoS2 yolk-shell spheres with an average diameter of about 500 nm have been synthesized by a facile route. When evaluated as anodes for lithium-ion and sodium-ion batteries, these Co9 S8 /MoS2 yolk-shell spheres show high specific capacities, excellent rate capabilities, and good cycling stability.

An incompletely condensed polyvinylsilsesquioxane (PVSQ) oligomer containing abundant silanol groups was synthesized and characterized by FTIR, 1H-NMR, 29Si-NMR, and MALDI-TOF-MS. Polystyrene/polyvinylsilsesquioxane (PS/PVSQ) hybrid composites were prepared by an in situ bulk polymerization. The hybrid composites showed higher Tg, Td, and char yield than PS homopolymer and without mechanical loss. The improvements in the properties of PS/PVSQ hybrid composites can be ascribed to the crosslinking function of PVSQ by silanol condensation in later processing. The hybrids showed different morphology from discrete microstructure to continuous network depending on the concentration of PVSQ. Because of the surface enrichment, a PVSQ protection layer was formed, which made the hybrid surface more hydrophobic. The structure and the reaction mechanism of PS/PVSQ hybrid composites were also investigated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Mass production of high quality graphene platelets has attracted considerable interest for potential applications in various fields. Nevertheless, in literature, the graphite oxide (GO)-derived graphene is always lacking high crystallinity and hierarchical porosity. Herein, we report a new molten sodium-induced graphitization for mass-fabricating highly crystalline and porous graphene sheets. The 3D graphene hydrogels (GHs) obtained from GO by the hydrothermal self-assembly are directly annealed in molten sodium at 800 °C. As a result, the D band intensity in Raman spectroscopy is reduced significantly, while 2D band intensity is increased prominently, which is a typical characteristic of highly crystalline graphene. More importantly, the resulting Na-GFs-800 sample exhibits increased surface area and narrow mesopore size distribution (~3.6 nm). The excellent supercapacitive performance of Na-GFs-800 has been demonstrated in an organic symmetric system. Meanwhile, the possible interaction mechanism between molten sodium and GHs has been proposed in the text.

A new approach for the fabrication of γ-AlOOH nanoflake films has been developed. The nanoflakes were successfully formed on a glass substrate via a simple, low temperature, and seed-assisted hydrothermal technique. A large amount of γ-AlOOH nanoflakes with various thicknesses interlaced together, resulting in a nest-like layer of film with their sharp edges preferentially vertical to glass substrates. The effects of hydrothermal temperature, time and concentration on the morphology and phase of the γ-AlOOH nanoflake films are investigated. X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Raman microscopy were used to characterize the structures and morphologies of the films. The growth mechanism of the γ-AlOOH nanoflake films was also discussed. Moreover, the nanostructural films of γ-AlOOH showed a transition from hydrophilic to super-hydrophobic with the chemical vapor deposition of PFOS.

Highly uniform core–shell structured polyaniline–multiwall carbon nanotube nanocomposites have been successfully prepared by noncovalent coating of a polyaniline shell on the wall of MWNTs with the assistance of 1-pyrenesulfonic acid. It is found that 1-pyrenesulfonic acid plays important roles in dispersing MWNTs and directing the polymerization of the polyaniline shell by the sulfonic groups. The obtained nanocomposites exhibit a higher specific capacitance. This research provides a new approach for designing core–shell hybrid materials with potential application in high-performance electrochemical supercapacitors.

A simple procedure was developed to fabricate uniform-sized hollow organic-inorganic silica spheres with a golf ball-like wrinkled surface. Two precursors, methyltrimethoxylsilane and tetraethoxysilane were hydrolyzed in solution of ammonia, and the hollow morphology was obtained by co-condensation of the two precursors, followed by self-assembly of silica and polymeric organoalkoxysilane. The composition of the two precursors and temperature were of importance for the morphological characteristics of organic-inorganic silica spheres. In addition, their size and distribution can be controlled by the dispersion manner of precursors into aqueous solution of ammonia. The framework components indicated the presence of silica and polymethylsilsesquioxane, and polymethylsilsesquioxane was distributed on the surface of the microspheres. Self-assembly of silica and polymethylsilsesquioxane based on Ostwald ripening process was proposed to explain the formation of hollow structures and golf ball-like wrinkled surface.