Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore, Karnataka 560012, India.
ACS Nano. 2011 Oct 25;5(10):7713-21. doi: 10.1021/nn202262j. Epub 2011 Oct 10.
We develop lightweight, multilayer materials composed of alternating layers of poly dimethyl siloxane (PDMS) polymer and vertically aligned carbon nanotube (CNT) arrays, and characterize their mechanical response in compression. The CNT arrays used in the assembly are synthesized with graded mechanical properties along their thickness, and their use enables the creation of multilayer structures with low density (0.12-0.28 g/cm(3)). We test the mechanical response of structures composed of different numbers of CNT layers partially embedded in PDMS polymer, under quasi-static and dynamic loading. The resulting materials exhibit a hierarchical, fibrous structure with unique mechanical properties: They can sustain large compressive deformations (up to ∼0.8 strain) with a nearly complete recovery and present strain localization in selected sections of the materials. Energy absorption, as determined by the hysteresis observed in stress-strain curves, is found to be at least 3 orders of magnitude larger than that of natural and synthetic cellular materials of comparable density. Conductive bucky paper is included within the polymer interlayers. This allows the measurement of resistance variation as a function of applied stress, showing strong correlation with the observed strain localization in compression.
我们开发了由聚二甲基硅氧烷（PDMS）聚合物和垂直排列的碳纳米管（CNT）阵列交替层组成的轻质多层材料，并对其在压缩下的机械响应进行了表征。用于组装的 CNT 阵列沿其厚度具有分级的机械性能，其使用使得能够创建具有低密度（0.12-0.28 g/cm³）的多层结构。我们在准静态和动态加载下测试了部分嵌入 PDMS 聚合物中的不同数量 CNT 层组成的结构的机械响应。所得到的材料具有分层的纤维状结构，具有独特的机械性能：它们可以承受高达约 0.8 的大压缩变形，几乎完全恢复，并在材料的选定部分出现应变局部化。通过在应力-应变曲线上观察到的滞后现象确定的能量吸收至少比具有可比密度的天然和合成多孔材料大 3 个数量级。导电巴基纸包含在聚合物层间。这允许测量电阻变化作为施加应力的函数，显示与压缩下观察到的应变局部化的强烈相关性。
