Fakultät für Naturwissenschaften, Technische Universität Chemnitz, 09107 Chemnitz, Germany.
ACS Nano. 2011 Jun 28;5(6):4886-91. doi: 10.1021/nn200957g. Epub 2011 May 16.
We observe unexpected locally auxetic behavior in elastomeric polypropylene, a semicrystalline polymer with a natural microstructure and a low degree of crystallinity. Our series of scanning force microscopy images show the nanomechanical deformation processes that occur upon stretching a thin film of elastomeric polypropylene. Upon uniaxial stretching, the angle between epitaxially grown lamella branches remains constant and the lamellae elongate, resulting in locally auxetic behavior (negative Poisson's ratio) on the 100-nanometer scale. This mechanism causing auxetic behavior, which was previously proposed on the basis of geometric arguments, appears to be an intrinsic property of certain semicrystalline polymers.
我们在半结晶聚合物弹性聚丙烯中观察到了出乎意料的局部负泊松比行为，这种聚合物具有天然的微观结构和较低的结晶度。我们的一系列扫描力显微镜图像显示了在拉伸弹性聚丙烯薄膜时发生的纳米力学变形过程。在单轴拉伸时，外延生长的片层分支之间的角度保持不变，而片层伸长，导致在 100 纳米尺度上出现局部负泊松比（负泊松比）行为。这种导致负泊松比行为的机制以前是基于几何论点提出的，似乎是某些半结晶聚合物的固有特性。
