Yu Liu

Ternary Ag/epoxy adhesive with excellent overall performance.

Excellent electrical conductivity (EC) generally conflicts with high lap shear strength (LSS) for electrically conductive adhesives (ECAs) since EC increases while LSS decreases with increasing conductive filler content. In this work, the ECAs with the excellent overall performance are developed based on the ternary hybrid of Ag microflakes (Ag-MFs), Ag nanospheres (Ag-NSs), and Ag nanowires (Ag-NWs). First, a low silver content adhesive system is determined. Then, the effects of the relative contents of Ag fillers on the EC and the LSS are studied. It is shown that a small amount of Ag-NSs or Ag-NWs can dramatically improve the EC for the Ag-MF/epoxy adhesives. The Ag-NSs and Ag-NWs with appropriate contents have a synergistic effect in improving the EC. Meanwhile, the LSS of the as-prepared adhesive with the appropriate Ag contents reaches an optimal value. Both the EC and the LSS of the as-prepared ternary hybrid ECA with a low content of 40 wt % Ag are higher than those of the commercial ECAs filled with the Ag-MF content over 60 wt %. Finally, the ternary hybrid ECA with the optimal formulation is shown to be promising for printing the radio frequency identification tag antennas as an immediate application example.

Facile surfactant-free synthesis of monodisperse Ni particles via a simple solvothermal method and their superior catalytic effect on thermal decomposition of ammonium perchlorate

Successful synthesis of monodisperse nickel particles with narrow particle size distributions is reported for the first time via a simple solvothermal method with ultrasonic treatment using no surfactants. The Ni products are characterized by X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. The as-synthesized monodisperse Ni particles show a spherical morphology with the mean particle size of 46.2, 60.1 and 113.7 nm for the reaction time of 0.5, 1 and 3 h, respectively at a low temperature of 100 degrees C. The catalytic effect is investigated for the Ni particles on the thermal decomposition of ammonium perchlorate (AP) using differential thermal analysis and thermogravimetry. For the purpose of comparison, as-prepared and commercial non-monodisperse Ni particles are used for examining the catalytic effect. The monodisperse Ni particles show a superior catalytic effect over the non-monodisperse Ni counterparts with a similar mean particle size. The surface areas of Ni particles are measured by Brunauer-Emmett-Teller (BET) technique. A theoretical consideration is also presented for analysis of the surface areas of monodisperse and non-monodisperse particles. Both the BET and theoretical results show that the surface area of monodisperse particles is higher than that of non-monodisperse counterparts. Consequently, the catalytic effect of Ni particles on thermal decomposition of AP is explained in terms of the surface areas.

Synthesis and molecular structure of arene ruthenium(II) benzhydrazone complexes: impact of substitution at the chelating ligand and arene moiety on antiproliferative activity

A convenient method for the synthesis of ruthenium(II) arene benzhydrazone complexes (1–6) of the general formula [(η6-arene)Ru(L)Cl] (arene-benzene or p-cymene; L-monobasic bidentate substituted indole-3-carboxaldehye benzhydrazone derivatives) has been described. The complexes have been fully characterized via elemental analysis, IR, UV-vis, NMR and ESI-MS spectral methods. The solid-state molecular structures of the representative complexes were determined using a single-crystal X-ray diffraction study and the results indicated the presence of a pseudo octahedral (piano stool) geometry. All the complexes were thoroughly screened for their cytotoxicity against human cervical cancer cells (HeLa), human breast cancer cell line (MDA-MB-231) and human liver carcinoma cells (Hep G2) under in vitro conditions. Interestingly, the cytotoxic activity of complexes 3, 4 and 6 is much more potent than cis-platin with low IC50 values against all the cancer cell lines tested. Furthermore, the mode of cell death in the MDA-MB-231 cells was assessed via AO–EB staining, Hoechst 33258 staining, flow cytometry and comet assay. Furthermore, the results of Western blot analyses suggest that complexes 3 and 6 accumulate preferentially in the mitochondria of MDA-MB-231 cells and induce apoptosis via mitochondrial pathways by up-regulating p53 and Bax, and down-regulating Bcl-2.

Enhancement in mode II interlaminar fracture toughness at cryogenic temperature of glass fiber/epoxy composites through matrix modification by carbon nanotubes and n-butyl glycidyl ether

A typical diglycidyl ether of bisphenol-F (DGEBF)/diethyl toluene diamine (DETD) epoxy system modified by multiwalled carbon nanotubes (MWCNTs) and a reactive aliphatic diluent named n-butyl glycidyl ether (BGE) was used as the matrix for glass fiber composites. The glass fiber (GF) reinforced composites based on the unmodified and modified epoxy matrices were prepared by the hand lay-up hot-press process. Mode II interlaminar fracture toughness at both room temperature (RT) and cryogenic temperature (77K) of the GF reinforced epoxy composites was investigated to examine the effect of the matrix modification. The result showed that the introduction of MWCNTs and BGE at their previously reported optimal contents led to the remarkable enhancement in mode II interlaminar fracture toughness of the composites. Namely, the 22.9% enhancement at RT and the 31.4% enhancement at 77K were observed for mode II interlaminar fracture toughness of the fiber composite based on the optimally modified epoxy matrix by MWCNTs and BGE compared to the unmodified case.