0D–2D Quantum Dot: Metal Dichalcogenide Nanocomposite Photocatalyst Achieves Efficient Hydrogen Generation

Hydrogen generation via photocatalysis‐driven water splitting provides a convenient approach to turn solar energy into chemical fuel. The development of photocatalysis system that can effectively harvest visible light for hydrogen generation is an essential task in order to utilize this technology. Herein, a kind of cadmium free Zn–Ag–In–S (ZAIS) colloidal quantum dots (CQDs) that shows remarkably photocatalytic efficiency in the visible region is developed. More importantly, a nanocomposite based on the combination of 0D ZAIS CQDs and 2D MoS₂ nanosheet is developed. This can leverage the strong light harvesting capability of CQDs and catalytic performance of MoS₂ simultaneously. As a result, an excellent external quantum efficiency of 40.8% at 400 nm is achieved for CQD‐based hydrogen generation catalyst. This work presents a new platform for the development of high‐efficiency photocatalyst based on 0D–2D nanocomposite.     

Synergistic effects of two types of ionic liquids on the dispersion of multiwalled carbon nanotubes in ethylene–vinyl acetate elastomer: preparation and characterization of flexible conductive composites

Flexible conductive composites based on an elastomer, ethylene–vinyl acetate copolymer (EVM), and multiwalled carbon nanotubes (MWCNTs) were fabricated by melt‐blending and subsequent crosslinking. Two types of ionic liquids (ILs), tributylmethylammonium bis(trifluoromethanesulfonyl)imide and 1‐ethyl‐3‐methylimidazolium tetrafluoroborate, were used to modify the MWCNTs for the purpose of improving their dispersion in the polymer matrix. It was found that the MWCNTs modified by an individual IL form agglomerates in the EVM matrix, while the MWCNTs modified by the two types of ILs simultaneously disperse in the EVM matrix homogeneously. Moreover, nanocomposites based on the MWCNTs modified with the combination of the two ILs exhibit improved mechanical and electrical properties. The mechanism of such synergistic effects was investigated. It was found that EVM is miscible with tributylmethylammonium bis(trifluoromethanesulfonyl)imide and it is immiscible with 1‐ethyl‐3‐methylimidazolium tetrafluoroborate. On the other hand, MWCNTs show stronger interaction with 1‐ethyl‐3‐methylimidazolium tetrafluoroborate than tributylmethylammonium bis(trifluoromethanesulfonyl)imide. Therefore, the uniform dispersion of MWCNTs in the EVM matrix is attributed to ‘bridging’ effects of the two ILs due to the different interactions of the two ILs with MWCNTs and EVM. The application of MWCNTs modified with two types of ILs in a polymer matrix opens a new fabrication strategy for high‐performance polymer nanocomposites. © 2017 Society of Chemical Industry     

Study of the effect of the concentration,size and surface chemistry of zirconia and silica nanoparticle fillers within an epoxy resin on the bulk properties of the resulting nanocomposites

Epoxy resin nanocomposites were prepared by curing bisphenol‐F with an aliphatic amine in the presence of SiO₂ and ZrO₂ nanoparticles as inorganic fillers. Both types of particles were prepared with diameters of around 10 nm and 70 nm to study size effects in the nanocomposites. The nanoparticles showed a different constitution: while silica was amorphous and spherical in nature, zirconia was crystalline and non‐spherical. Both nanoparticles were surface‐functionalized with novel diethylene‐glycol‐based capping agents to increase the compatibility with the epoxy matrix. The organic functionalities were attached to the nanoparticle surface via phosphonic acid (zirconia) and trialkoxysilane (silica) anchor groups. The homogeneity of the distribution of surface‐modified inorganic nano‐sized fillers in the matrix up to 5.8 vol% in case of silica and 2.34 vol% in case of zirconia was determined by small‐angle X‐ray scattering and transmission electron microscopy. Mechanical properties such as hardness and storage modulus were increased with increasing filler content while thermal stability of the obtained materials was nearly unaffected after incorporation of nanoparticles. Copyright © 2011 Society of Chemical Industry     

Tensile creep behaviour of polymethylpentene–silica nanocomposites

For the first time, poly(4‐methyl‐1‐pentene) (PMP) nanocomposites were prepared by melt compounding 2 vol% of fumed silica nanoparticles, in order to study the role of the nanofiller surface area and functionalization on the tensile mechanical response of the material, with particular focus on its creep behaviour. The high optical transparency of the polymer matrix was substantially preserved in the nanocomposites, while the mechanical properties (in particular the creep stability) were improved. Dynamic mechanical thermal analysis showed an improvement of the storage modulus, more evident above the glass transition temperature of the polymer matrix. Uniaxial tensile tests evidenced that the elastic modulus of the material was positively affected by the presence of silica nanoparticles, even if a slight reduction of the strain at break was detected. The reduction of the tensile creep compliance was proportional to the surface area of the nanofiller, being more evident at high stresses and elevated temperatures. Findley's law furnished a satisfactory fitting of the creep behaviour of the composites, even at high temperatures. It clearly emerges that the incorporation of fumed silica nanoparticles in PMP can be an effective way to overcome the problem of the poor creep stability of polyolefins, especially at high temperatures and high stresses. Moreover the possibility of retaining the original transparency of the material is fundamental for the production of completely transparent PMP components. Copyright © 2010 Society of Chemical Industry     

Effect of nanoclay and ZnO on the physical and chemical properties of wood polymer nanocomposite

Wood polymer composite (WPC) was prepared by using solution blended high density polyethylene, low density polyethylene, polypropylene, and poly(vinyl chloride) with Phragmites karka wood flour and polyethylene‐co‐glycidyl methacrylate (PE‐co‐GMA). The effect of addition of nanoclay and ZnO on the properties of the composite was examined. The distribution of silicate layers and ZnO nanopowder was studied by X‐ray diffractrometry and transmission electron microscopy. The improvement in miscibility among polymers due to addition of PE‐co‐GMA as compatibilizer was studied by scanning electron microscopy. WPC treated with 3 phr each of clay and ZnO showed an improvement in thermal stability and UV resistance. Mechanical and flame retarding properties were also enhanced after the incorporation of clay/ZnO nanopowder. Both water and water vapor absorption were found to decrease due to inclusion of nanoclay and ZnO in WPC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

纳米材料的应用及新进展

介绍了纳米粒子的优异特性。着重介绍了聚合物／无机纳米粒子复合材料的主要制备方法，研究现状及应用和2000年聚合物粘土纳米复合材料的最新进展。     

Organic–inorganic polyimide nanocomposites containing a tetrafunctional polyhedral oligomeric silsesquioxane amine: synthesis,morphology and thermomechanical properties

5,11,14,17‐Tetraanilinooctaphenyl double decker silsesquioxane, a well‐defined tetraamino polyhedral oligomeric silsesquioxane (POSS), was synthesized in this work. This novel tetrafunctional POSS amine was employed to prepare polyimide nanocomposites. It was found that the hybrid polyimide nanocomposites displayed nanostructures in which the POSS component was aggregated into spherical microdomains with a diameter of 40 ? 80 nm. Compared to unmodified polyimide, the POSS‐containing polyimide nanocomposites displayed improved thermal stability and surface hydrophobicity. Owing to the introduction of the POSS microdomains, the dielectric constants of the polyimide nanocomposites were significantly decreased in comparison with plain polyimide. © 2017 Society of Chemical Industry     

Detecting structural orientation in isoprene rubber/multiwall carbon nanotube nanocomposites at different scales during uniaxial deformation

Enhanced strain‐induced crystallization (SIC) behavior in isoprene rubber/multiwall carbon nanotube (IR/MWCNT) nanocomposites was analyzed in terms of structural orientation during uniaxial deformation. In situ synchrotron wide‐angle X‐ray diffraction and small‐angle X‐ray scattering (SAXS) reveal the molecular orientation in IR/MWCNT composites at different scales. The inclusion of MWCNTs leads to a decrease in the molecular orientation at small strain due to the promotion of SIC. Meanwhile, the presence of MWCNTs induces a large‐scale orientation within the vulcanized rubber network based on SAXS results. Considering the heterogeneous nature of the vulcanized network, the nucleation process during SIC is discussed from the viewpoint of thermodynamics. The oriented large‐scale structure in IR/MWCNT composites is composed of local rubber chains stretched up MWCNTs, from which the additional nuclei are induced. By forming a bound rubber layer around MWCNTs through attractive interactions, MWCNTs can amplify the local strain of rubber segments and form a highly oriented large‐scale structure, but without altering the overall molecular orientation level. The evolution of detailed structural orientation in MWCNT‐filled rubber composites during deformation is revealed for the first time. © 2017 Society of Chemical Industry     

Synthesis and antimicrobial activity of biocidal polymer–montmorillonite nanocomposites

The bioactive agents p‐hydroxymethylbenzoate, 2,4‐dihydroxymethylbenzoate and methylsalicylate were reacted with polyoxyalkylene (D_230–2000)–montmorillonite (MMT) intercalated nanocomposites. D_230–2000–MMT were prepared by an ion exchange process of Na‐MMT and? NH₃⁺ groups in polyoxyalkylene amine hydrochloride of three different molecular masses (D₂₃₀, D₄₀₀ and D₂₀₀₀). The results of X‐ray analysis and transmission electron microscopy show that D₂₀₀₀–MMT/p‐hydroxymethylbenzoate is an exfoliated nanocomposite, whereas in D₂₃₀–MMT/p‐hydroxymethylbenzoate, D₂₃₀–MMT/2,4‐dihydroxymethylbenzoate, D₂₃₀–MMT/methylsalicylate and D₄₀₀–MMT/p‐hydroxymethylbenzoate, having lower molecular mass and polymer loading, the MMT rearranges in an intercalated and flocculated structure. The amount of intercalated polymer and interaction between polymer and layered silicate were determined using thermogravimetric analysis and Infrared spectroscopy. The antimicrobial activities of the nanocomposites were qualitatively and quantitatively assessed by agar diffusion tests and minimal inhibitory concentration values against a Gram‐negative bacterium (Escherichia coli NCIM 2065), a Gram‐positive bacterium (Bacillus subtilis ATCC) and fungi (Candida albicans SC5314 and Cryptococcus neoformans). The D₂₀₀₀–MMT/p‐hydroxymethylbenzoate nanocomposite strongly inhibits the growth of all the micro‐organisms tested. The diameter of the inhibition zone varies according to the type of micro‐organism tested. The effect of nanocomposite concentration on morphology, respiration and release of calcium, potassium and sodium ions of the test micro‐organisms was examined. Copyright © 2011 Society of Chemical Industry