Composites of nanoporous gold and polymer.
Composites of nanoporous gold and polymer.
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DOI：
10.1002/adma.201203740
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发表时间：
2013-03-06
影响因子：
29.4
通讯作者：
Weissmueller, Joerg
中科院分区：
文献类型：
--
作者：
Wang, Ke;Weissmueller, Joerg
对细小物体--如微柱或纳米线--强度的实验研究通常指向强度随尺寸减小而增加的趋势，当尺寸下降到较低纳米区域时，[1-3]接近理论剪切强度。对无缺陷晶体(如晶须)的理论强度的观察表明，小的趋势与缺陷结构有关。[5-7]位错与表面的相互作用是另一个重要因素。在界面充电或电吸附过程中，现场观察到了巨大的可恢复流动应力变化。[8]无论其微观来源如何，小尺寸的高强度表明人们正在探索利用金属纳米结构的机械性能来生产高强度材料的设计策略。一个关键的挑战，即将许多(10 18×1 cm 3的材料，结构尺寸为10 nm)纳米物体组装成一个宏观物体，可以通过去合金化合成来克服。[9-11]该工艺提供了毫米或厘米大小的整体样品，由尺寸均匀的纳米“韧带”组成的均匀网络结构，可以控制到远低于10 nm。[12-14]通过透射电子显微镜、聚焦离子束成像和电子背散射衍射的研究，已经确定以这种方式制备的纳米多孔金属是多晶的，颗粒尺寸为10-100μm。16]每个微米大小的颗粒都是纳米多孔的，因此相邻的韧带共享相同的晶格。换句话说，体积为1μm 3的局部结构是包含连续的纳米尺度孔网的单晶的结构。这些材料的力学行为遵循为具有宏观孔隙率的泡沫推导的标度方程，而韧带的局部强度遵循与单个纳米线相同[3，17-19]或类似[16，20]的趋势。因此，这种材料，特别是纳米多孔金(NPG)，被作为尺寸效应对纳米结构塑性的模型系统进行了研究。值得注意的是，与许多其他纳米材料相比，NPG在压缩时可以变形为大的塑性应变，而其他许多纳米材料在几个百分比的变形后就失效了。类似于纳米管或纳米线，[4]单个纳米尺度
Experimental investigations of the strength of small objects–such as micropillars or nanowires–often point towards a trend of increasing strength with decreasing dimension,[1–3] approximating the theoretical shear strength when the size drops to the lower nanometer region.[1–4] The observation of theoretical strength in defect-free crystals, such as whiskers, irrespective of their size exemplifies that the trend of smaller is stronger is related to the defect structure.[5–7] The interaction of dislocations with the surface is another important factor, as is evidenced by in situ observation of large recoverable flow-stress changes during interfacial charging or electrosorption.[8] Irrespective of its microscopic origin, the high strength at small size suggests a search for design strategies that yield high-strength materials exploiting the mechanical properties of metal nanostructures. A key challenge, namely assembling many (10 18 for 1 cm 3 of material with a 10 nm structure size) nanoscale objects into a macroscopic body, can be overcome by synthesis via dealloying.[9–11] The process provides millimeter-or centimeter-sized monolithic samples consisting of a homogeneous network structure of nanoscale “ligaments” with uniform size that can be controlled down to well below 10 nm.[12–14] Investigations by transmission electron microscopy, focused ion beam imaging, and electron backscatter diffraction have established that nanoporous metals prepared in this way are polycrystalline with a grain size of 10–100 μm.[15, 16] Each micrometer-sized grain is nanoporous, so that neighboring ligaments share the same crystal lattice. In other words, the local structure in volumes of, say, 1 μm 3, is that of a single crystal containing a contiguous nanoscale pore network. The mechanical behavior of these materials obeys scaling equations derived for foams with macroscopic porosity, and the local strength of the ligaments follows the same [3, 17–19] or similar [16, 20] trends as individual nanowires. The material, and in particular nanoporous gold (npg), has thus been studied as a model system for size-effects on the plasticity of nanostructures.Significantly, npg can be deformed to large plastic strain in compression, in contrast to many other nanomaterials that fail after few percent of deformation.[21] The deformability of npg may be understood from the macroscopic constitutive behavior. Similar to nanopillars or nanowires,[4] the individual nanoscale
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影响因子：
1.9
作者：
Jin, Hai-Jun;Parida, Smrutiranjan;Weissmueller, Joerg
通讯作者：
Weissmueller, Joerg
影响因子：
8.6
作者：
LI, R;SIERADZKI, K
通讯作者：
SIERADZKI, K
影响因子：
8.6
作者：
Parida, S.;Kramer, D.;Weissmueller, J.
通讯作者：
Weissmueller, J.
DOI：
10.1016/s0921-5093(02)00608-1
发表时间：
2003-04-25
影响因子：
6.4
作者：
Kumar, PS;Ramachandra, S;Ramamurty, U
通讯作者：
Ramamurty, U
影响因子：
6.7
作者：
Aufray, Maelenn;Roche, Alain Andre
通讯作者：
Roche, Alain Andre