纳米Cu-Zn复合氧化物自组装合成及可见光催化性能

采用阴阳离子表面活性剂复合囊泡相为软模板,自组装合成了Cu-Zn复合氧化物纳米材料,分析了自组装过程。研究了铜的掺杂量对纳米材料的形貌、晶型、能级变化以及电子结构的影响,评价了不同铜掺杂量的ZnO-CuO样品光催化性能。结果表明,随着铜掺杂量的增加,样品ZnO-CuO中ZnO的X射线衍射(XRD)特征峰强度逐渐降低;形貌由多面体晶粒转向片层结构;铜的引入使ZnO的发光能级发生变化,并随着铜离子的量增加,光生载流子浓度变小。可见光催化结果显示,样品ZnO-CuO光催化性能随掺杂铜离子量的增加先增加后减弱。在金属离子Cu2+和Zn2+物质的量之比为5:95时光催化效果为最佳。

DNA分子组装体研究进展

DNA分子组装体在基因治疗、电子转移、分子器件和纳米材料构筑等方面具有很强的应用前景。本文对近几年来 DNA分子组装体的研究作了评述。

CdS/SiO_2 nanowire arrays and CdS nanobelt synthesized by thermal evaporation

CdS/SiO2 nanowire arrays and CdS nanobelts were synthesized by thermal evaporation of CdS and CdO mixture powders, with highly selective etching occurring on the silicon substrate surfaces. Study of the growth mechanism of CdS/SiO2 nanowire arrays and the growth process of CdS nanobelts showed that the growth of CdS dendrites plays an important role in the formation of CdS/SiO2 nanowire arrays, and that the mechanism of CdS/SiO2 nanowire arrays growth was in good agreement with “self-assembling nanoelectrochemistry”. In the thermal evaporation process, an interaction between Si from silicon substrate and Cd took place.

Monodisperse Ultra-Large-Pore Silica Coated Polystyrene Core-Shell Microbeads via Layer-by-Layer Assembly for Nano-Micro Composite

Polystyrene （PS） @SiO2 core-shell microbeads with large pore and large particle size were prepared via layer-by-layer（LBL）assembly technique for potential applications in nano-micro composites. Negative silica nanoparticles synthesized via modified St6ber method and cationic poly （diallyldimethylammonium chloride） were alternately adsorbed on the surface of microbeads. Zeta potential, size, and morphology of the microbeads were monitored during LBL assembly process to ensure the successful deposition of silica nanoparticles. The porous shell was characterized using nitrogen adsorption and desorption analyses, and the surface area, volume and diame- ter of the pores were derived. It is found that the porous shell thickness and the pore size can be tuned by changing the coating times of silica nanoparticles. Finally, PS@SiO2 core-shell microbeads with 5 grn PS solid core and 350 nm mesoporous shell （mean BJH pore diameter is ~27 nm） were used to load CdSe/ZnS quantum dots （QDs）. The fluorescence microscopic image and the optical amplification of the QDs-embedded microbeads （QDBs） indicate that the as-prepared core-shell microbeads can provide adequate space for QDs and may be useful for further application of nano-micro composites.

Role of self-assembly in construction of inorganic nanostructural materials

Understanding the evolution process and formation mechanism of nanoscale structures is crucial to controllable synthesis of inorganic nanomaterials with well-defined geometries and unique functionalities. In addition to the conventional Ostwald ripening process, oriented aggregation has been recently found to be prevalent in nanocrystal growth. In this new mechanism, primary small nanocrystals firstly spontaneously aggregate in the manner of oriented attachment, and then the large crystalline materials are formed via the process of interparticle recrystallization. Furthermore, controllable fabrication of the ordered nanocrystal solid materials that has shown specific collective properties will promote the application of inorganic nanocrystal in devices. Therefore, investigation of the mechanism of oriented aggregation is essential to controllable synthesis of nanocrystals and ordered nanocrystal solid materials. In this review, we summarize recent advances in the preparation of nanocrystal materials, which are mostly focused on our work about the role of self-assembly in construction of inorganic nanostructural materials.

Self-assembled energetic coordination polymers based on multidentate pentazole cyclo-N_5^-

Coordination to form polymer is emerging as a new technology for modifying or enhancing the properties of the existed energetic substances in energetic materials area. In this work, guanidine cation CN3 H6+ (Gu) and 3-amino-1,2,4-triazole C2H4N4(ATz) were crystallized into NaN5 and two novel energetic coordination polymers(CPs),(NaN5)5[(CH6-N3)N5](N5)3–(1) and(NaN5)2(C2H4N4)(2) were prepared respectively via a self-assembly process. The crystal structure reveals the co-existence of the chelating pentazole anion and organic component in the solid state. In polymer 1, Na+and N5– were coordinated to form a cage structure in which guanidine cation [C(NH2)3]+ was trapped;for polymer 2, a mixedligand system was observed;N5 – and ATz coordinate separately with Na+and form two independent but interweaved nets. In this way, coordination polymer has been successfully utilized to modify specific properties of energetic materials through crystallization. Benefiting from the coordination and weak interactions, the decomposition temperatures of both polymers increase from 111°C(1D structure [Na(H2 O)(N5)]?2 H2 O) to 118.4 and 126.5°C respectively. Moreover, no crystallized H2 O was generated in products to afford the anhydrous compounds of pentazole salts with high heats of formation( >800 kJ mol–1). Compared to traditional energetic materials, the advantage in heats of formation is still obvious for the cyclo-N5– based CPs, which highlights cyclo-N5– as a promising energetic precursor for high energy density materials(HEDMs).

Uptake of magnetic nanoparticles for adipose-derived stem cells with multiple passage numbers

With the increasingly promising role of nanomaterials in tissue engineering and regenerative medicine, the interaction between stem cells and nanoparticles has become a critical focus. The entry of nanoparticles into cells has become a primary issue for effectively regulating the subsequent safety and performance of nanomaterials in vivo. Although the influence of nanomaterials on endocytosis has been extensively studied, reports on the influence of stem cells are rare.Moreover, the effect of nanomaterials on stem cells is also dependent upon the action mode. Unfortunately, the interaction between stem cells and assembled nanoparticles is often neglected. In this paper, we explore for the first time the uptake of γ-Fe2O3 nanoparticles by adipose-derived stem cells with different passage numbers. The results demonstrate that cellular viability decreases and cell senescence level increases with the extension of the passage number. We found the surface appearance of cellular membranes to become increasingly rough and uneven with increasing passage numbers. The iron content in the dissociative nanoparticles was also significantly reduced with increases in the passage number. However, we observed multiple-passaged stem cells cultured on assembled nanoparticles to have similarly low iron content levels. The mechanism may lie in the magnetic effect of γ-Fe2O3 nanoparticles resulting from the field-directed assembly. The results of this work will facilitate the understanding and translation of nanomaterials in the clinical application of stem cells.

Facile construction of quasi 1D trimanganese tetraoxide nanostructures via soft templating

Self-assembly of nanocrystals can not only lead to a better understanding of inter-particle acting force, but also enable rational building of complex and functional materials for future nanodevices. Here by utilizing polyvinylpyrrolidone （PVP） as the as capping and structure directing agents, hierarchical Mn304 architectures involving coil-like nanorings, hexagonal nanoframes, and nanodisks are conveniently synthesized by a one-pot solution method. The sophisticated assemblies are proven to be me- diated by the PVP soft templates formed at varied concentrations. The driving forces of self-assembled complex nanostructures and the unique role of PVP concentration are discussed. Magnetic properties of the as assembled Mn3O4 rings are also studied by a SQUID system, which shows the typical side effect of Curie temperature.