Novel method for mechanical characterization of polymeric nanofibers
Novel method for mechanical characterization of polymeric nanofibers
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DOI：
10.1063/1.2771092
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发表时间：
2007-08-01
影响因子：
1.6
通讯作者：
Dzenis, Yuris
中科院分区：
文献类型：
--
作者：
Naraghi, Mohammad;Chasiotis, Ioannis;Dzenis, Yuris
提出了一种对高变形纳米纤维进行纳米尺度力学表征的新方法。采用外接压电传感器驱动的片上片簧式称重传感器，构建了用于光纤夹持和力测量的微机电系统（MEMS）测试平台。在光学显微镜下进行亚微米尺度的拉伸试验。通过数字图像相关提取器件部件的相对刚体位移，直接从MEMS平台图像中获取工程应力和应变。用这种光学方法测定位移的精度优于50 nm。在该方法的应用中，研究了直径为300 ~ 600 nm的静电纺聚丙烯腈纳米纤维的力学行为。应力-应变曲线表现出明显的弹-完美塑性特性，弹性模量为7.6 +/- 1.5 GPa，不可逆应变大于220%。大的纤维拉伸比是在纳米纤维冷拉伸过程中形成的周期性颈级联的结果。
A novel method to perform nanoscale mechanical characterization of highly deformable nanofibers has been developed. A microelectromechanical system (MEMS) test platform with an on-chip leaf-spring load cell that was tuned with the aid of a focused ion beam was built for fiber gripping and force measurement and it was actuated with an external piezoelectric transducer. Submicron scale tensile tests were performed in ambient conditions under an optical microscope. Engineering stresses and strains were obtained directly from images of the MEMS platform, by extracting the relative rigid body displacements of the device components by digital image correlation. The accuracy in determining displacements by this optical method was shown to be better than 50 nm. In the application of this method, the mechanical behavior of electrospun polyacrylonitrite nanofibers with diameters ranging from 300 to 600 nm was investigated. The stress-strain curves demonstrated an apparent elastic-perfectly plastic behavior with elastic modulus of 7.6 +/- 1.5 GPa and large irreversible strains that exceeded 220%. The large fiber stretch ratios were the result of a cascade of periodic necks that formed during cold drawing of the nanofibers.