聚苯乙烯重氮盐的单组分逐层自组装研究

利用聚苯乙烯重氮盐(PS-DAS),通过单组分逐层自组装,得到了厚度可控的超薄膜.采用紫外可见光谱,椭偏仪,原子力显微镜等对自组装膜的增长和表面形貌进行了表征,并对其交联前后的性质进行了研究.结果表明,利用逐层自组装步骤可以制备膜厚均匀增长的PS-DAS膜.组装过程中的吹干步骤对自组装膜的增长起重要作用.在加热条件下,超薄膜可以发生交联反应,得到疏水的表面。     

具有蜂窝内壁的遮光罩杂散光抑制特性分析

将具有蜂窝内壁结构的遮光罩内的杂散光传播分解为蜂窝结构的散射、内壁等效面传播两个层次的行为。通过建立蜂窝结构的等效面各向异性反射模型,采用蒙特卡罗法模拟获得内壁等效面的双向反射分布函数(BRDF)。以此为基础,再次采用蒙特卡罗法模拟遮光罩内壁等效面的杂散光传播过程,分析了该类遮光罩的杂散光抑制特性,并讨论了蜂窝高度和涂层反射率的影响。结果表明,遮光罩内壁蜂窝结构有很好的杂散光抑制作用;蜂窝高度与边长之比δ≥1时,遮光罩的抑制能力不再变化,降低涂层反射率能够有效地增强抑制效果。     

Raspberry-like composite polymer particles by self-assemble heterocoagulation based on a charge compensation process

Nano-sized poly(ethylene glycol dimethacrylate-co-acylic acid) (poly(EGDMA-co-AA)) were effectively self-assembled on poly(divinylbenzene-co-styryl methylpyridinium chloride) (poly(DVB-co-StMPyCl)) surfaces to form the raspberry-like composite by a charge compensation mechanism through the affinity complex between carboxylic group and pyridinium group. The effects of pH and salt electrolyte on the morphology of the self-assembled polymer composites were investigated. The resulting heterocoagulates were highly stable in water and acid solution. These heterocoagulates were reversible through the self-assembly in acidic or neutral media and the dissociation in the basic medium due to the charge compensation through the strong affinity complex between hydroxide anion and pyridinium group cation. The resulting heterocoagulates were characterized with scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). As a result, a new method for tuning the structure of a charge compensation directed polymer composite was developed.     

超支化聚负离子/超支化聚正离子自组装膜的制备及反应

自1991年以来,静电吸附自组装已发展成为制备具有特定纳米微结构聚电介质多层超薄膜的有效技术。近年来,由于树枝状聚合物和超支化聚合物独特的物理化学性质,文献中已将它们与线性聚电解质一起用于静电吸附自组装过程,但完全基于超支化聚合物分子间的自组装过程还鲜见报道,超支化聚合物所具有的大量末端和内部（如叔胺基）官能团,不仅可以用于调节自组装行为及组装膜的表面形貌,     

Synthesis of P(MBA-co-MAA) microsphere-grafted PAMAM dendrimers and their application as supporters for gold nanoparticles

Poly(N,N′-methylenebisacrylamide-co-acrylic acid) microsphere-supported polyamidoamine (PAMAM) dendrimers up to third generation (G) were grown onto the surface as well as the gel-layer of P(MBA-co-MAA) microspheres by a divergent method. The P(MBA-co-MAA) supported PAMAM dendrimers were used as heterogeneous stabilizers for the gold nanoparticles by an in situ reduction of HAuCl₄ via the efficient coordination interaction between the amino groups of the supported PAMAM dendrimers and the gold atoms. The effects of the generations of the P(MBA-co-MAA) supported PAMAM dendrimer on the loadings and the catalytic activity of the heterogeneous Au nanoparticles were systematically investigated with the reduction of 4-nitrophenol to 4-aminophenol as a model reaction.     

Gilbert damping in the layered antiferromagnet CrCl3

We theoretically and experimentally studied the Gilbert damping evolution of both acoustic and optical magnetic resonance modes in the layered flake Cr Cl;with an external magnetic field H applied in plane.Based on a Lagrangian equation and a Rayleigh dissipation function,we predicted that the resonance linewidth△H as a function of microwave frequencyωis nonlinear for both acoustic and optical modes in the Cr Cl;flake,which is significantly different from the linear relationship of△H-ωin ferromagnets.Measuring the microwave transmission through the Cr Cl;flake,we obtained theω–H dispersion and damping evolution△H–ωfor both acoustic and optical modes.Combining both our theoretical prediction and experimental observations,we concluded that the nonlinear damping evolution△H–ωis a consequence of the interlayer interaction during the antiferromagnetic resonance,and the interlayer Gilbert dissipation plays an important role in the nonlinear damping evolution because of the asymmetry of the non-collinear magnetizaiton between layers.     

Thermoelectric Properties and Stability of Nanocomposites Type I Clathrate Ba-Cu-Si with SiC

Thermoelectric (TE) materials attract interest for the capability of converting waste heat into electricity. Nanostructuring is considered as an effective approach to improve the conversion efficiency by reducing the lattice thermal conductivity. Nanostructured materials are metastable due to the high interface energy of grain boundaries, therefore they lose easily the nanostructure features during the thermal cycling at high temperatures, i.e., showing instabilities in TE properties. Here we show the structural/microstructural stability of type I clathrate nanocomposites in the Ba-Cu-Si system with SiC as the secondary phase. SiC has no influence on the crystal structure of the type I clathrate and very limited contributions to the grain size reduction and size-growth prevention during the ball milling and hot pressing processes, but stabilizes the TE properties during thermal cycling. A high bulk density and as low as possible contamination in nanocomposites are essential for high TE performance and high stability in nanostructured materials.     

云纹干涉法在新材料细观力学实验研究中的应用

本文介绍了云纹干涉法用于新材料细观力学实验研究的几个典型例子，实验结果不仅为这些新材料的细观本构理论研究提供了重要的实验依据，同时也表明云纹干涉法是固体材料细观力学实验研究的有效手段之一。最后简要地分析了云纹干涉法在细观力学实验研究中的测量能力。