ZIF-8/丙烯酸十四-十六酯共聚物和PB/丙烯酸十四-十六酯共聚物形状稳定相变材料的制备与性能

形状稳定的相变材料(SPCMs)是绿色的可重复使用的储能材料。由于丙烯酸正烷基酯共聚物的熔融温度可通过控制侧链长度来调节,因此可以得到适宜的相变温度。用一种基于金属-有机骨架纳米粒子稳定悬浮聚合法制备出了功能MOFs/聚合物复合材料—ZIF-8/丙烯酸十四-十六酯共聚物(ZIF-8/P(TDA-co-HDA))与PB/丙烯酸十四-十六酯共聚物(PB/P(TDA-co-HDA)),通过使用此技术,可以将功能性纳米颗粒固定在聚合物表面上,ZIF-8和PB起到形状稳定的作用。ZIF-8/P(TDA-co-HDA)的吸放热温度分别为37.5℃和8.4℃,相变焓值为63 J/g,PB/P(TDA-co-HDA)在39.1℃吸热,10.1℃放热,相变焓值为68 J/g。该种材料在60℃时保持其形状没有任何泄漏,这远高于P(TDA-co-HDA)的熔融温度。在1000个热循环后,ZIF-8/P(TDA-co-HDA)和PB/P(TDA-co-HDA)仍表现出良好的结晶行为和热可靠性。制备的新型形状稳定相变材料在热能存储应用中具有潜在的用途。      

Nanoparticles@nanoscale metal-organic framework composites as highly efficient heterogeneous catalysts for size-and shape-selective reactions

Composites incorporating nanoparticles (NPs) within metal-organic frameworks (MOFs) find applications in many different fields.In particular,using MOF layers as molecular sieves built on the NPs could enable selectivity in heterogeneous catalysis.However,such composites typically exhibit low catalytic efficiency,due to the slow diffusion of the reactants in the long and narrow channels of the MOF shell.In order to improve the catalytic efficiency of these systems,here we report the fabrication of NPs incorporated in nanosized MOFs (NPs@nano-MOFs),obtained by reducing the size of the MOF crystals grown around the NPs.The crystal size of the composites was controlled by modulating the nucleation rate of the MOFs during the encapsulation of pre-synthesized and catalytically active NPs;in this way,NPs@MOF crystals smaller than 50 nm were synthesized and subsequently used as highly efficient catalysts.Due to the shorter path from the MOF surface to the active sites,the obtained Pt@nano-MOFs composites showed a higher conversion rate than their larger-sized counterparts in the synthesis of imines via cascade reaction of nitrobenzene and in the hydrogenation of olefins,while retaining the excellent size and shape selectivity associated with the molecular sieving effect of the MOF layer.The present strategy can also be applied to prepare other encapsulated nanostructures combining various types of NPs and nano-MOFs,thus highlighting the broad potential of this approach for developing optimized catalysts with high reactivity and selectivity.     

Facile fabrication of superior antibacterial cotton fabric based on ZnO nanoparticles/quaternary ammonium salts hybrid composites and mechanism study

In the research for the safe and efficiently antibacterial cotton fabrics to minimize risk for human health, an organic–inorganic hybrid material of ZnO nanoparticles (NPs) and quaternary ammonium salt (QAS) was employed to modify cotton fabrics by a dipping–padding–drying method. The synergistic effects of ZnO NPs and QAS on the structure and antibacterial properties of cotton fabrics were studied in detail. Results displayed that the QAS and ZnO NPs were immobilized firmly in cotton fabric by the formation of chemical covalent bonds and silica gel structure. ZnO/QAS/cotton had a good inhibitory effect on the growth of E. coli and S. aureus, with superior antibacterial efficiency of >99.99%. ZnO/QAS/cotton preserved good mechanical property, water absorbability, and limpness. We also provided a detailed analysis of antibacterial mechanism for the hybrid materials. The contact mechanism and the Zn²⁺ release were considered as the main mechanisms for the ZnO/QAS/cotton, while the reactive oxygen species (ROS) generation only had a little contribution to the antibacterial activity. In short, the excellent integrated properties endowed the hybrid cotton fabrics as potential application in many fields, like healthcare, food packaging.     

Few layer graphene/silver nanocomposite based flexible and resistive liquefied petroleum gas sensor

The LPG gas sensing characteristics of hybrid few-layered graphene (FLG)/ silver nanoparticles (Ag NPs) nanoarchitecture have been investigated. FLG and silver nanoparticles (Ag NPs) enhance the LPG gas sensing characteristics by collectively involving in the electronic transportation and diffusion mechanisms. FLG, Ag and FLG/ Silver nanocomposites are developed by ultra-sonication assisted method, and the effect of flexibility on gas sensing performance was thoroughly examined. The sensing materials as thin films are developed via drop-casting technique on photo lithography patterned flexible interdigitated electrodes (IDEs). The gas sensing characteristics of the prepared sensor are studied for LPG and other analytes at room temperature. The maximum response is observed for FLG/Ag nanocomposite to 100 ppm LPG at room temperature. FLG/Ag nanocomposite sensor demonstrates rapid response, high selectivity, reproducibility and good stability over a period of 30 days. Further the durability and flexibility tests conducted for the FLG/Ag hybrid sensor at bending angles reveal 78% stability even after 15 days of sensing studies.

     

具有三维网状结构的石墨相氮化碳/还原氧化石墨烯/钯复合材料的合成及可见光催化性能

石墨相氮化碳(g-C_3N_4)已经被认为是一种高效的非金属半导体光催化剂。为进一步优化其光催化性能,通过热解-水热两步法制备了三维网状结构的g-C_3N_4/还原氧化石墨烯(rGO)/钯纳米颗粒(Pd NPs)复合材料。该复合材料由大量超薄片组成,而且薄片上有大量直径约为10nm的Pd NPs。g-C_3N_4/rGO/Pd NPs复合材料展现了一个宽的可见光吸收(边~460nm),其在460~800nm波长范围内还有一个随波长增加的光吸收。经可见光(λ400nm)照射140 min后,g-C_3N_4/rGO/Pd NPs复合材料可降解90%罗丹明B(RhB)。此外,循环实验表明g-C_3N_4/rGO/Pd NPs复合材料具有良好的稳定性。因此,g-C_3N_4/rGO/Pd NPs复合材料有望成为一种高效稳定的光催化剂,在水污染处理领域具有潜在的应用价值。     

细菌纤维素抗菌复合材料的制备和应用

目的 综述细菌纤维素抗菌复合材料在国内外的研究和应用现状,以制备具有优异抗菌性能的细菌纤维素复合材料.方法 总结细菌纤维素抗菌复合材料的抗菌性及其最新合成方式,包括与无机抗菌剂、有机抗菌剂结合或添加抗生素等方式合成细菌纤维素抗菌复合材料,并进一步阐述细菌纤维素抗菌复合材料的应用领域.结论 细菌纤维素复合材料的抗菌性能优异,在医学、食品包装和净水等领域都有较大的应用潜力,有待进一步系统研究.     

Inorganic nanoparticles and the microbiome

Routine exposure to inorganic nanoparticles (NPs) that are incorporated into consumer products such as foods/drinks, packaging materials, pharmaceuticals, and personal care products (e.g. cosmetics, sunscreens, shampoos) occurs on a daily basis. The standard everyday use of these products facilitates interactions between the incorporated inorganic NPs, mammalian tissues (e.g. skin, gastrointestinal tract, oral cavity), and the community of microbes that resides on these tissues. Changes to the microbiome have been linked to the initiation/ progression of many diseases and there is a growing interest focused on understanding how inorganic NPs can initiate these changes. As these mechanisms are revealed and defined, it may be possible to rationally design microbiotamodulating therapies based on inorganic NPs. In this article, we will: (i) provide a background on inorganic NPs that are commonly found in consumer products such as those that incorporate titanium, zinc, silver, silica, or iron, (ii) discuss how NP properties, microbiota composition, and the physiological microenvironment can mediate the effects that inorganic NPs have on the microbiota, and (iii) highlight opportunities for inorganic NP therapies that are designed to interact with, and navigate, the microbiome.     

Reduced graphene oxide-metal/metal oxide composites: facile synthesis and application in water purification

This paper describes a versatile, and simple synthetic route for the preparation of a range of reduced graphene oxide (RGO)-metal/metal oxide composites and their application in water purification. The inherent reduction ability of RGO has been utilized to produce the composite structure from the respective precursor ions. Various spectroscopic and microscopic techniques were employed to characterize the as-synthesized composites. The data reveal that the RGO-composites are formed through a redox-like reaction between RGO and the metal precursor. RGO is progressively oxidized primarily to graphene oxide (GO) and the formed metal nanoparticles are anchored onto the carbon sheets. Metal ion scavenging applications of RGO-MnO(2) and RGO-Ag were demonstrated by taking Hg(II) as the model pollutant. RGO and the composites give a high distribution coefficient (K(d)), greater than 10 L g(-1) for Hg(II) uptake. The K(d) values for the composites are found to be about an order of magnitude higher compared to parent RGO and GO for this application. A methodology was developed to immobilize RGO-composites on river sand (RS) using chitosan as the binder. The as-supported composites are found to be efficient adsorbent candidates for field application.     

Enhanced catalytic performances of Ag nanoparticles supported on layered double hydroxide for styrene epoxidation

Catalysts or support to catalysts based on layered double hydroxides (LDHs) have been widely investigated in the last few years. Supported Au nanoparticles (NPs), prepared typically by a homogeneous deposition–precipitation technique, have been utilized as catalysts with high activity and selectivity for styrene epoxidation. We herein present a preparation of chemically reduced and cost-saving Ag NPs on the LDH support used as catalyst for styrene epoxidation. A proper reaction condition is optimized, for example, a loading of 2.67 wt% Ag, a conversion temperature of 82 °C, and a conversion time of 8 h. The Ag/LDH catalyst exhibits enhanced reaction selectivity and product yield in comparison with the Au/LDH reported previously. Our results may initiate a facile framework appropriate for noble metallic NPs supported on layered inorganic crystal compounds.     

Synthesis of Ag‐NPs impregnated cellulose composite material: its possible role in wound healing and photocatalysis

Cellulose is the natural biopolymer normally used as supporting agent with enhanced applicability and properties. In present study, cellulose isolated from citrus waste is used for silver nanoparticles (Ag‐NPs) impregnation by a simple and reproducible method. The Ag‐NPs fabricated cellulose (Ag‐Cel) was characterised by powder X‐rays diffraction, Fortier transform infrared spectroscopy and scanning electron microscopy. The thermal stability was studied by thermo‐gravimetric analysis. The antibacterial activity performed by disc diffusion assay reveals good zone of inhibition against Staphylococcus aureus and Escherichia coli by Ag‐Cel as compared Ag‐NPs. The discs also displayed more than 90% reduction of S. aureus culture in broth within 150 min. The Ag‐Cel discs also demonstrated minor 2,2‐diphenyl 1‐picryl‐hydrazyl radical scavenging activity and total reducing power ability while moderate total antioxidant potential was observed. Ag‐Cel effectively degrades methylene‐blue dye up to 63.16% under sunlight irradiation in limited exposure time of 60 min. The Ag‐NPs impregnated cellulose can be effectively used in wound dressing to prevent bacterial attack and scavenger of free radicals at wound site, and also as filters for bioremediation and wastewater purification.Inspec keywords: silver, nanoparticles, particle reinforced composites, nanocomposites, filled polymers, wounds, nanomedicine, biomedical materials, photochemistry, catalysis, X‐ray diffraction, Fourier transform infrared spectra, scanning electron microscopy, thermal stability, thermal analysis, antibacterial activity, dyes, wastewater treatment, contaminated site remediation, nanofabricationOther keywords: silver nanoparticles, impregnated cellulose composite, wound healing, photocatalysis, natural biopolymer, citrus waste, powder X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermal stability, thermo‐gravimetric analysis, antibacterial activity, disc diffusion assay, Staphylococcus aureus, Escherichia coli, inhibition zone, broth, 2,2‐diphenyl 1‐picryl‐hydrazyl radical scavenging activity, total reducing power ability, total antioxidant potential, methylene‐blue dye, sunlight irradiation, wound dressing, bacterial attack, free radical scavenger, wastewater purification, bioremediation filters, wound site, time 60 min, Ag     

Hierarchical Metal/Semiconductor Nanostructure for Efficient Water Splitting

A hierarchically patterned metal/semiconductor (gold nanoparticles/ZnO nanowires) nanostructure with maximized photon trapping effects is fabricated via interference lithography (IL) for plasmon enhanced photo‐electrochemical water splitting in the visible region of light. Compared with unpatterned (plain) gold nanoparticles‐coated ZnO NWs (Au NPs/ZnO NWs), the hierarchically patterned Au NPs/ZnO NWs hybrid structures demonstrate higher and wider absorption bands of light leading to increased surface enhanced Raman scattering due to the light trapping effects achieved by the combination of two different nanostructure dimensions; furthermore, pronounced plasmonic enhancement of water splitting is verified in the hierarchically patterned Au NPs/ZnO NWs structures in the visible region. The excellent performance of the hierarchically patterned Au NPs/ZnO NWs indicates that the combination of pre‐determined two different dimensions has great potential for application in solar energy conversion, light emitting diodes, as well as SERS substrates and photoelectrodes for water splitting.     

Enhanced photocatalytic activity by the construction of a TiO<Subscript>2</Subscript>/carbon nitride nanosheets heterostructure with high surface area via direct interfacial assembly

A TiO2 heterostructure modified with carbon nitride nanosheets (CN-NSs) has been synthesized via a direct interfacial assembly strategy.The CN-NSs,which have a unique two-dimensional structure,were favorable for supporting TiO2 nanoparticles (NPs).The uniform dispersion of TiO2 NPs on the surface of the CN-NSs creates sufficient interfacial contact at their nanojunctions,as was confirmed by electron microscopy analyses.In comparison with other reported metal oxide/CN composites,the strong interactions of the ultrathin CN-NSs layers with the TiO2 nanoparticles restrain their re-stacking,which results in a large specific surface area of 234.0 m2·g-1.The results indicate that the optimized TiO2/CN-NSs hybrid exhibits remarkably enhanced photocatalytic efficiency for dye degradation (with k of 0.167 min-1 under full spectrum) and H2 production (with apparent quantum yield =38.4％ for,λ =400 ± 15 nm monochromatic light).This can be ascribed to the improved surface area and quantum efficiency of the hybrid,with a controlled ratio that reaches the appropriate balance between producing sufficient nanojunctions and absorbing enough photons.Furthermore,based on the identification of the main active species for photodegradation,and the confirmation of active sites for H2 evolution,the charge transfer pathway across the TiO2/CN-NSs interface under simulated solar light is proposed.     

Inorganic Nanotube/Organic Nanoparticle Hybrids for Enhanced Photoelectrochemical Properties

Inorganic/organic nanohybrids composed of arrayed TiO_2 nanotubes(Ti NTs)/porphyrin nanoparticles(NPs) have been fabricated via a wet chemical approach. The inorganic component, particularly the arrayed one-dimensional(1D) nanostructures, provides high charge-carrier mobility and rapid charge transport. The organic component exhibits extensive visible light absorption and good solution processability. Additionally, the geometric restraint by supramolecular assembly renders an improved photostability. A combination of these two components could thus allow for an efficient solar energy conversion. In this work, a colloid of porphyrin NPs prepared by a solvent exchange method is coated on anodic Ti NTs by means of a dip-coating treatment to form inorganic/organic hybrids. The hybrids exhibit an improvement on solar absorption and a significant enhancement on photocurrent generation at a small bias compared with individual component. Herein, the inorganic/organic nanohybrids are proved to be excellent photoanodes highly responsive to visible light and thus pave a way to discover new inorganic/organic assemblies for high-performance optoelectronic applications, as well as for device integration.     

Molecularly imprinted Au nanoparticles composites on Au surfaces for the surface plasmon resonance detection of pentaerythritol tetranitrate, nitroglycerin, and ethylene glycol dinitrate

Molecularly imprinted Au nanoparticles (NPs) composites are generated on Au-coated glass surfaces. The imprinting process involves the electropolymerization of thioaniline-functionalized Au NPs (3.5 nm) on a thioaniline monolayer-modified Au surface in the presence of a carboxylic acid, acting as a template analogue for the respective explosive. The exclusion of the imprinting template from the Au NPs matrix yields the respective imprinted composites. The binding of the analyte explosives to the Au NPs matrixes is probed by surface plasmon resonance spectroscopy, SPR, where the electronic coupling between the localized plasmon of the Au NPs and the surface plasmon wave leads to the amplification of the SPR responses originating from the dielectric changes of the matrixes upon binding of the different explosive materials. The resulting imprinted matrixes reveal high affinities and selectivity toward the imprinted explosives. Using citric acid as an imprinting template, Au NPs matrixes for the specific analysis of pentaerythritol tetranitrate (PETN) or of nitroglycerin (NG) were prepared, leading to detection limits of 200 fM and 20 pM, respectively. Similarly, using maleic acid or fumaric acid as imprinting templates, high-affinity sensing composites for ethylene glycol dinitrate (EGDN) were synthesized, leading to a detection limit of 400 fM for both matrixes.     

Temperature and anion responsive self-assembly of ionic liquid block copolymers coating gold nanoparticles

In this paper, double hydrophilic ionic liquid block copolymers (ILBCs), poly poly[1-methyl-3-(2-methacryloyloxy propylimidazolium bromine)]-block-(N-isopropylacrylamide) (PMMPImB-b-PNIPAAm) was first synthesized by reversible addition-fragmentation chain transfer (RAFT) and then attached on the surface of gold nanoparticles (Au NPs) via a strong gold-sulfur bonding for preparing hybrid nanoparticles (PMMPImB-b-PNIPAAm-@-Au NPs). The hybrid NPs had a three layers micelle-like structure, including a gold core, thermo-responsive inner shell and anion responsive outer corona. The self-assembling behavior of thermal- and anion-response from shell and corona were respectively investigated by change of temperature and addition of (CF₃SO₂)₂N^-. The results showed the hybrid NPs retained a stable dispersion beyond the lower critical solution temperature (LCST) because of the space or electrostatic protecting by outer PMMPImB. However, with increasing concentration of (CF₃SO₂)₂N^-, the micellization of self-assembling PMMPImB-b-PNIPAAm-@-Au NPs was induced to form micellar structure containing the core with hydrophobic PMMPImB-(CF₃SO₂)₂N^- surrounded by composite shell of Au NPs-PNIPAAm via the anion-responsive properties of ILBCs. These results indicated that the block copolymers protected plasmonic nanoparticles remain self-assembling properties of block copolymers when phase transition from outer corona polymer.     

Preparation and properties of cotton stalk carbon/gold nanoparticles composite

In this paper, cotton stalk is used as a low-cost raw material source to prepare activated carbon with a unique porous structure with the assistance of chemical treatment. Gold nanoparticles as a multifunction building block were in situ assembled onto the carbon material, endowing this hybrid more promising applications. The as-fabricated CS carbon/AuNPs hybrid materials have been demonstrated to behave with catalytic and photothermal conversion properties, indicating that AuNPs successfully functionalise the activated carbon. The catalytic activity of the hybrid showed a glucose concentration-dependent effect (as low as 5 × 10^?6 M). The water temperature of the sample containing the CS carbon/Au NPs increased rapidly, and even reached 55 °C, only exposed to light for 5 min. When used as catalyst of reduction of p-nitrophenol, the hybrid showed a good reusability up to10 cycles.     

Surface‐functionalised hybrid nanoparticles for targeted treatment of cancer

Cancer is a leading cause of death worldwide. Despite the great advancement in understanding the pharmacology and biology of cancer, it still signifies one of the most serious human‐health related problems. The current treatments for cancer may include surgery, radiotherapy, and chemotherapy, but these procedures have several limitations. Current studies have shown that nanoparticles (NPs) can be used as a novel strategy for cancer treatment. Developing nanosystems that allow lower doses of therapeutic agents, as well as their selective release in tumour cells, may resolve the challenges of targeted cancer therapy. In this review, the authors discuss the role of the size, shape, and surface modifications of NPs in cancer treatment. They also address the challenges associated with cancer therapies based on NPs. The overall purpose of this review is to summarise the recent developments in designing different hybrid NPs with promising therapeutic properties for different types of cancer.Inspec keywords: tumours, reviews, patient treatment, nanomedicine, surgery, radiation therapy, cellular biophysics, nanobiotechnology, nanoparticles, cancerOther keywords: current treatments, cancer treatment, targeted cancer therapy, cancer therapies, surface‐functionalised hybrid nanoparticles, targeted treatment, serious human‐health related problems     

Controlled AFM manipulation of small nanoparticles and assembly of hybrid nanostructures

We demonstrate controlled manipulation of semiconductor and metallic nanoparticles (NPs) with 5-15 nm diameters and assemble these NPs into hybrid structures. The manipulation is accomplished under ambient environment using a commercial atomic force microscope (AFM). There are particular difficulties associated with manipulating NPs this small. In addition to spatial drift, the shape of an asymmetric AFM tip has to be taken into account in order to understand the intended and actual manipulation results. Furthermore, small NPs often attach to the tip via electrostatic interaction and modify the effective tip shape. We suggest a method for detaching the NPs by performing a pseudo-manipulation step. Finally, we show by example the ability to assemble these small NPs into prototypical hybrid nanostructures with well-defined composition and geometry.     

Polyaniline/Pt Hybrid Nanofibers: High‐Efficiency Nanoelectrocatalysts for Electrochemical Devices

A simple and facile procedure to synthesize a novel hybrid nanoelectrocatalyst based on polyaniline (PANI) nanofiber‐supported supra‐high density Pt nanoparticles (NPs) or Pt/Pd hybrid NPs without prior PANI nanofiber functionalization at room temperature is demonstrated. This represents a new type of 1D hybrid nanoelectrocatalyst with several important benefits. First, the procedure is very simple and can be performed at room temperature using commercially available reagents without the need for templates and surfactants. Second, ultra‐high density small “bare” Pt NPs or Pt/Pd hybrid NPs are grown directly onto the surface of the PANI nanofiber, without using any additional linker. Most importantly, the present PANI nanofiber‐supported supra‐high density Pt NPs or Pt/Pd hybrid NPs can be used as a signal enhancement element for constructing electrochemical devices with high performance.     

Electrospun titania fibers by incorporating graphene/Ag hybrids for the improved visible-light photocatalysis

A novel graphene/Ag nanoparticles (NPs) hybrid (prepared by a physical method (PM)) was incorporated into electrospun TiO₂ fibers to improve visible-lightdriven photocatalytic properties. The experimental study revealed that the graphene/Ag NPs (PM) hybrid not only decreased the bandgap energy of TiO₂, but also enhanced its light response in the visible region due to the surface plasmon resonance (SPR) effect. In addition, compared with those of TiO₂ fibers incorporating the graphene/Ag NPs hybrid (prepared by a chemical method (CM)), TiO₂-graphene/Ag NPs (PM) fibers exhibited a higher surface photocurrent density and superior photocatalytic performance, i.e., the visible-light-driven photocatalytic activity was enhanced by 2 times. The main reasons include a lower surface defect density of the graphene/Ag NPs (PM) hybrid, a smaller particle size (10 nm) and a higher dispersity of Ag NPs, which promote the rapid transfer of photoexcited charge carriers and inhibit the recombination of photogenerated electrons and holes. It is expected that this kind of ternary electrospun fibers will be a promising candidate for applications in water splitting, solar cells, CO₂ conversion and optoelectronic devices, etc.