CRYSTALLINE NETWORKS WITH UNUSUAL PREDICTED MECHANICAL AND THERMAL-PROPERTIES
CRYSTALLINE NETWORKS WITH UNUSUAL PREDICTED MECHANICAL AND THERMAL-PROPERTIES
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DOI：
10.1038/365735a0
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发表时间：
1993-10-21
期刊：
影响因子：
64.8
通讯作者：
GALVAO, DS
中科院分区：
文献类型：
--
作者：
BAUGHMAN, RH;GALVAO, DS
大多数材料横向收缩，拉伸时密度降低。从基本观点和实际观点来看，横向膨胀（即具有负泊松比）和拉伸时致密化的材料都是令人感兴趣的1 -5。一些负泊松比的单晶相是已知的3，4，但这些不致密时拉伸。在这里，我们提出的分子力学计算的一些假设阶段的碳表现出这两种行为。这些性质来自于在延伸的螺旋链中作为铰链的键的存在。这些相的其他不寻常的性质包括负热膨胀，掺杂剂控制的孔隙率和低温多晶型。这样的结构可以设想用于聚乙炔、聚二乙炔、聚亚苯基和（BN）x相，以及用于一些已知的结构相关的无机相的变体。
MOST materials shrink laterally and become less dense when stretched. Materials that both expand laterally (that is, have negative Poisson's ratio) and densify when stretched are of interest both from the fundamental and the practical points of view1-5. A few monocrystalline phases with negative Poisson's ratio are known3,4, but these do not densify when stretched. Here we present molecular-mechanics calculations for some hypothetical phases of carbon which exhibit both kinds of behaviour. The properties derive from the presence of bonds that act as hinges in extended helical chains. Other unusual properties of these phases include negative thermal expansion, dopant-controlled porosity and low-temperature polymorphism. Such structures can be envisaged for polyacetylene, polydiacetylene, polyphenylene and (BN)x phases, as well as for variants of some known, structurally related inorganic phases.