材料期刊网

Effect of Amino-, Methyl- and Epoxy-Silane Coupling as a Molecular Bridge for Formatting a Biomimetic Hydroxyapatite Coating on Titanium by Electrochemical Deposition

Tan Guoxin , Ouyang Kongyou , Wang Hang , Zhou Lei , Wang Xiaolan , Liu Yan , Zhang Lan , Ning Chengyun

材料科学技术（英文） doi:10.1016/j.jmst.2016.07.012

The objective of this study was to determine the role of functional groups of silane coupling on bioactive titanium (Ti) surface by electrochemical deposition, and calcium phosphate (CaP) coating, as well as bone cell adhesion and proliferation. Methyl group (—CH₃), amino group (—NH₂), and epoxy group (—glyph name—C(O)C) were introduced onto the bioactive Ti surface using self-assembled monolayers (SAMs) with different silane coupling agents as molecular bridges. The effect of the surface functional groups on the growth features of the CaP crystals was analyzed (including chemical compositions, element content, minerals morphology and crystal structure etc.). CH₃-terminated SAMs showed a hydrophobic surface and others were hydrophilic by contact angle measurement; NH₂-terminated SAMs showed a positive charge and others were negatively charged using zeta-potential measurement. Scanning electron microscopy results confirmed that flower-like structure coatings consisting of various pinpoint-like crystals were formatted by different functional groups of silane coupling, and the CaP coatings were multicrystalline consisting of hydroxyapatite (HA) and precursors. CaP coating of CH₃-terminated SAMs exhibited more excellent crystallization property as compared to coatings of —NH₂ and —C(O)C groups. In vitro MC3T3-E1 cells adhesion and proliferation were performed. The results showed that CaP coatings on silane coupling functionalized surfaces supported cell adhesion and proliferation. Thus, these functional groups of silane coupling on Ti can form homogeneous and oriented nano-CaP coatings and provide a more biocompatible surface for bone regeneration and biomedical applications.

关键词: Silane coupling , Molecular bridge , Calcium phosphate coatings , Titanium , Electrochemical deposition

Controllable Protein Adsorption and Bacterial Adhesion on Polypyrrole Nanocone Arrays

Zhou Zhengnan , Li Weiping , He Tianrui , Yu Peng , Tan Guoxin , Ning Chengyun

材料科学技术（英文） doi:10.1016/j.jmst.2016.06.023

In this research, polypyrrole nanocone arrays doped with β-Naphthalene sulphonic acid (PPy-NSA) were built. This film was expected to control protein adsorption and bacterial adhesion by potential-induced reversibly redox. The scanning Kelvin probe microscopy (SKPM) and surface contact angles (SCA) tests suggested that the surface potential and wettability of PPy-NSA nanocone arrays could be controlled by simply controlling its redox property via applying potential. The controllable surface potential and wettability in return controlled the adsorption of protein and adhesion of bacteria. The proposed material might find application in the preparation of smart biomaterial surfaces that can regulate proteins and bacterial adhesion by a simple potential switching.

关键词: Polypyrrole , Protein adsorption , Bacterial adhesion , Nanocone arrays , Control

Improving the electrochemical properties of natural graphite spheres by coating with a pyrolytic carbon shell

新型炭材料

Two kinds of modified natural graphite (MNG) spheres with a pyrolytic carbon shell on smooth or granular surface were obtained using fluidized bed chemical vapor deposition of acetylene by adjusting the reaction parameters. The core of the NING has a highly ordered graphite structure and the shell has a disordered structure. Compared with natural graphite (NG) spheres, MNG with a core-shell structure shows improved first cycling efficiency and cyclability. Especially, the NING spheres with a granular surface possess 84% retention of the first discharge capacity after 41 cycles, owing to effective decrease of the contact resistance and increase of contact area between the NING spheres.

关键词: fluidized bed chemical vapor deposition;core-shell structure;pyrolytic;carbon;modified natural graphite;lithium ion secondary battery;lithium-ion batteries;chemical-vapor-deposition;1st-cycle charge loss;anode material;encapsulated graphite;surface-area;infiltration;performance;improvement;pyrocarbon

STUDIES ON PRIMARY CRYSTALLIZATION OF RAPIDLY QUENCHED Al-Ni-Cu-Nd METALLIC GLASS BY USING HIGH RESOLUTION TRASMISSION ELECTRON MICROSCOPY

Y.D.Xiao , W.X.Li , D.Jacovkis , M.T.Clavaguera-Mora , J.Rodriguez-Viejo , N.Clavaguera

金属学报(英文版)

Rapidly solidified Al87Ni7Cu3Nd3 metallic glasses, prepared by using melt spinning, were treated under both isothermal and non-isothermal regime. The amorphous rib-bon and the annealed samples were closely examined by means of differential scan-ning calorimetric, conventional X-ray diffraction and high resolution transmission electron microscopy with selected-area electron diffraction, with special interest in pri-mary crystallization into α-Al nanocrystalline particles, in order to understand struc-tural characteristics of Al-based amorphous/nanocrystalline alloys, and nucleation and grain growth mechanism on the nanometer scale during primary crystallization. The results show that, the as-prepared ribbons are fully amorphous and homogeneous in the micron scale, but contain high density of quenched-in clusters or crystallite embryos. Primary crystallization mainly leads to formation of two-phase mixture of α-Al crystal and residual amorphous phase. The annealed ribbons exposed isother-mally at 110℃ for 5, 130 minutes and heated continuously up to less than 310℃ at 40℃/min consist of large amount of α-Al fec crystal nanoparticles dispersed uni-formly in an amorphous matrix. However, a very little amount of finer orthorhombic Al3Ni intermetalics particles exist in the annealed ribbons heated up to 310℃. During primary crystallization, the leading kinetic mechanics to impede growth of the α-Al crustal is soft impinaement, instead of geometric impinqement.

关键词: rapid solidification , null , null