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Abstract We designed a graphene oxide (GO) supported silver nanoparticles (AgNPs) nanocomposite via polyvinyl-pyrrolidone (PVP) and isopropanol (IPA) assisted gamma irradiation, in which GO contained abundant functional groups and AgNPs were endowed with monodispersed spherical shape. The graphite oxide was intercalated by the imidazole silver nitrate as the precursor, and then the AgNPs in the interlamellar of graphite oxide was reduced and grown via induction of gamma irradiation with IPA and PVP. Meanwhile, the size of AgNPs was limited by confinement effects of GO and fragmentation capability of gamma irradiation. IPA controlled the reduction of GO and the PVP endowed AgNPs with single crystal spherical structure and monodisperse size. And the as-prepared nanocomposites were applied in the nitrite detection as an electrochemical sensing platform. We found that the nanocomposites containing abundant oxygen-containing functional groups had a higher faradaic current than reduced nanocomposites. Spherical AgNPs decorated on GO obtained the most sensitive electrode among all samples and the detection limit for nitrite was 0.24 μM which preceded that of most reported materials. The as-prepared sensor was well selective to nitrite in presences of NaH 2 PO 4 , Na 2 SO 4 , NaCl, NaNO 3 and Na 2 CO 3. An effective approach was presented to develop the controllable synthesis of silver nanoparticle-functionalized graphene nanocomposites via gamma irradiation in application of electrochemical detection for nitrite ions in this work. Highlights • Graphite oxide was used as raw material to in-situ produce functionalized graphene-silver nanoparticle nanocomposites. • PVP, graphite oxide and gamma irradiation demonstrated a synergistic effect to AgNPs in monodispersed spherical structure. • IPA controlled the reduction of graphene oxide in gamma irradiation. • The as-prepared composites showed a detection limit of nitrite of 0.24 μM which preceded that of most reported materials. [ABSTRACT FROM AUTHOR]

In order to investigate the effect of the addition of carbon nanotubes (CNTs) in carbon fibers reinforced epoxy matrix composites (CF/EP) on the ability of composites to resist γ radiation. We used γ irradiation and investigated composites, γ-CF/EP without CNTs; γ-CF/EP with CNTs in matrix (γ-CF/EP-CNTs); γ-CF/EP with CNTs in interface (γ-CF-CNTs/EP) and γ-CF/EP with CNTs both in the interface area and matrix (γ-CF-CNTs/EP-CNTs). The results show that the bending strength and bending modulus of γ-CF-CNTs/EP-CNTs are 28.59% and 41.44% higher than that of γ-CF/EP before fatigue testing, and 32.19% and 73.51% higher than that of gamma-CF/EP after fatigue testing. Ultrasonic C-scan microscopic examination after fatigue test showed that the internal structure damage of γ-CF-CNTs/EP-CNTs was the smallest, while γ-CF/EP was the largest. The storage modulus of the three modified composites are significantly improved compared with the unmodified composite, especially the storage modulus of γ-CF-CNTs/EP-CNTs is sharply improved from 2.53 GPa (γ-CF/EP) to 5.66 GPa (γ-CF-CNTs/EP-CNTs). X-ray spectroscopy shows changes in the surface and internal valence content of the composites, further revealing the crosslinking reaction and the secondary curing reaction. Combined with scanning electron microscopy and crack propagation models, the microstructure and enhancement mechanisms of CNTs-reinforced composites for anti-gamma radiation are discussed. The CNTs synergistic enhance the composite's anti-gamma radiation performance with excellent effects when CNTs are added together into matrix and interface area. [ABSTRACT FROM AUTHOR]

Highlights • The flower-like PtAu/rGO nanocomposites were obtained by the gamma irradiation assisted with microemulsion. • Gamma irradiation could efficiently reduce GO and metal precursors to rGO and PtAu NPs. • Microemulsion endowed PtAu NPs with monodisperse flower-like morphology and inhibited the agglomeration of nanoparticles. • The immunosensor based on the flower-like PtAu/rGO exhibited excellent performance for the detection of CEA. Abstract The platinum-gold (PtAu)/reduced graphene oxide (rGO) nanocomposites were obtained via the gamma irradiation assisted by microemulsion while PtAu NPs showed the monodispersed flower-like shape with small-sized (below 15 nm). Gamma irradiation controlled the reduction of graphene oxide and PtAu NPs meanwhile the microemulsion endowed PtAu NPs with porous monodisperse flower-like structure and inhibited the agglomeration of nanoparticles. The size of PtAu NPs was limited by confinement effects of graphene oxide and fragmentation ability of gamma irradiation. An ultra-sensitive, label-free immunosensor was developed on the base of above rGO supported PtAu alloy nanoparticles for the determination of carcinoma embryonic antigen (CEA). The flower-like PtAu/rGO nanocomposites had a higher faradaic current than other nanocomposites, and the obtained PtAu NPs/rGO nanocomposites not only improve the electrocatalytic activity and increase the electrode surface area in nanoscale dimension, but also provide a stable and biocompatible matrix for the convenient conjugation of antibody, thus providing a high-efficiency immunoassay platform. The developed immunosensor showed excellent performance for the detection of CEA with a low detection limit of 7 fg·mL−1 and a wide dynamic range from 10 fg·mL−1 to 1 × 108 fg·mL−1. In addition, the immunosensor system showed high specificity with the interference of ascorbic acid, bovine serum albumin, L-tryptophan and alpha fetal protein. The contribution of this work lies in the research of the synergistic effect of gamma irradiation and microemulsion in the formation of flower-like PtAu NPs/rGO nanoparticles applied in preparation of immunosensor. In view of the versatility of self-assembled nanoparticles, this strategy has great application prospects in fabrication of immunosensors and other biological devices. [ABSTRACT FROM AUTHOR]

Abstract Further modification of carbon and transition metal composites has become a hot spot in the preparation of anode materials for lithium ion battery, including various morphologies, nitrogen doping and porous introduction. However, the synergistic effect of specific surface area and nitrogen doping content of composite materials on the electrochemical performance as anode materials for lithium ion batteries has not been revealed. In this paper, the carbon nanofibers loaded with titanium dioxide are fabricated via electrospinning method followed by calcination process with simple addition admixture of diisopropyl azodiformate in precursor solution. The pores are introduced into the composite with controllable nitrogen doping and surface area simultaneously. The specific capacity of titanium dioxide @carbon nanofibers has been increased from 192.2 mAh g−1 to 336 mAh g−1 due to the increased nitrogen content of the composite from 7.18% to 10.21%, and elevated specific surface area from 67.23 to 111.15 m2 g−1, which can endow the composite superior conductivity and more active sites. The capacity contribution of the total specific capacity has decreased from 60.8% to 44.7% compared with original sample, proving that increasing diffusion controlled Faradaic Li-ion insertion origins from nitrogen doping. Graphical abstract Image 1 Highlights • Composite with controllable nitrogen doping and surface area simultaneously is fabricated with addition of DIPA. • The electrochemical performance of the composite with improved surface area and nitrogen doping content is studied. • Superior electrochemical performance of freestanding TiO 2 @CNFs as anodes for lithium-ion batteries is exhibited. [ABSTRACT FROM AUTHOR]

Abstract Recently, in order to increase the electrical conductivity of the phosphorus-based anode materials and to alleviate the deterioration of the electrochemical performance caused by the volume expansion of red phosphorus, the composite material made of red phosphorus and carbon matrix has become the mainstream route for lithium ion batteries. In this work, we used one-pot ball milling method to synthesize an unique rebar-reinforced concrete structure hybrid of nanosized phosphorus particles, multi-walled carbon nanotubes, and carbon black (CNTs/CB@P composites). The carbon nanotubes formed a primary frame network structure and the CB formed a regional secondary network structure in the CNTs/CB@P composites, which makes red phosphorus covered by double network structure. Such a structure greatly improves the conductive network of CNTs/CB@P composites for lithium ion batteries. Furthermore, this one-pot ball milling method was simple, continuous, and much suitable for industrial production. When the ratio of multi-walled carbon nanotubes to carbon black was 3:2, the CNTs/CB@P composites had the cycling performance with a reversible capacity of ~ 474.9 mAh g−1 and a capacity retention of ~ 56.3% after 50 cycles. [ABSTRACT FROM AUTHOR]

N -Alkylated chitosan (NACS) may improve the haemostatic efficiency of chitosan (CS). To study its coagulation capability and function, a series of NACS with various carbon chain lengths and substitution degrees (SD) of alkyl groups were synthesized and characterized by FTIR, NMR, and elemental analysis. Haemolysis and toxicity assays revealed that NACS showed good biocompatibility. In vitro blood clotting tests indicated that NACS had better haemostatic activity than CS, of which N -octadecyl CS with 3.85% SD showed the best results. Blood plasma coagulation tests showed that NACS was not favourable for activating coagulation factors. Platelet adhesion, intracellular Ca 2+ , and CD62p measurements demonstrated that the coagulation properties of NACS were not related to platelet activation. Erythrocyte adhesion examination indicated that blood coagulation of NACS may be attributable to its effects on erythrocytes. This study suggests that NACS is an ideal candidate for clotting. [ABSTRACT FROM AUTHOR]

• A triple-layered ultra-thin double Janus nanofiltration membrane was prepared with substrate membrane, carboxylated cellulose interlayer and ultra-thin polyamide layer. • The hydrophobic/hydrophilic, positive/negative Janus structure of nanofiltration membrane was helpful to separate Mg2+ and Li+. • The thickness of polyamide layer in Janus nanofiltration membrane was 60.29 nm, 55.56% thinner than that in traditional nanofiltration membrane and 25.89% thinner than that in weak Janus nanofiltration membrane. To explore nanofiltration (NF) membrane with high permeability and good separation for Li+ from salt-lake, a triple-layered ultra-thin double Janus NF membrane was prepared with polyethersulfone (PES) substrate membrane, a carboxylated cellulose nanocrystal (CNC-COOH) interlayer and an ultra-thin polyamide (PA) layer via interfacial polymerization of polyethylenimine and trimesoyl chloride. The interlayer contain a large number of carboxyl groups, which could improve not only the negative potential of interlayer, but also the positive potential of the PA layer because of the increase of unreacted NH 2. In addition, the hydrophilic of interlayer was stronger than the PA layer. Therefore, the interlayer and the ultra-thin PA layer could construct a double Janus NF membrane with hydrophobic/hydrophilic, positive/negative charge. It was found that the content of carboxyl groups and unreacted amino groups on the surface of Janus PES/CNC-COOH/PA NF membrane was increased obviously. The thickness of Janus NF membrane PA layer was 60.29 nm, 55.56% thinner than that in traditional PES/PA NF membrane and 25.89% thinner than that in weak Janus PES/cellulose nanocrystal/PA NF membrane. The Janus NF membrane had a minimum average surface roughness of 6.21 nm, an effective pore diameter of 1.38 nm, and exhibited a positive surface charge with a highly hydrophilic nature. Under the Mg2+/Li+ ratio of 30 and 60, the Janus NF membrane exhibited the rejection difference between Mg2+ and Li+ reached to 74.35% and 83.96%, the water flux was 4.17 and 3.4 L/(m2·h·bar), respectively, and the separation factor S Li,Mg was 12.15 and 5.84, respectively. [ABSTRACT FROM AUTHOR]