ME Seminar Series: Low-Dimensional Nanomaterials: from Mechanics to Stretchable Electronics
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Wednesday, November 6, 2013 - 11:30am to 1:00pm
Yong Zhu, NCSU
Recent advance in nanotechnology has brought about a host of nanomaterials, such as nanoparticles, nanowires, nanotubes and graphene that exhibit ultrahigh strength (e.g., sample-wide stress > 1/10 of their ideal strengths). Such nanomaterials are not only an ideal platform to study fundamental mechanics, but also important building blocks for a broad spectrum of nanotechnology applications. Here I present three related examples. The first example is on in-situ scanning and transmission electron microscopy (SEM/TEM) mechanical testing of crystalline nanowires. I will highlight metallic nanowires with Ag as an example. Ag nanowires exhibit strong size dependent elastic modulus and yield strength. Its unique five-fold twinned structure gives rise to the strain hardening behavior. The second example is on the interface mechanics between graphene and polymer substrates. Two interfacial failure mechanisms, shear sliding under tension and buckling under compression, are identified for monolayer graphene on plastic substrate using in-situ Raman and atomic force microscopy measurements. A nonlinear shear-lag model is used to relate the measurements to the interfacial properties including the shear strength and efficiency for stress transfer. I will conclude my talk with the third example, which is stretchable electronics based on 1D nanomaterials. I will discuss a particular type of device, highly conductive and stretchable electrodes based on Ag nanowires.