"Mechanics of two-dimensional materials in the three-dimensional space"
Prof. Jaehyung Yu
Dept. of Mechanical Engineering,
Chung Ang University
Host: Prof. Arend van der Zande (arendv@illinois.edu) - Contact if you are interested in meeting with the speaker.
The use of two-dimensional(2D) materials in nanoscale electro-mechanical applications, such as sensors, actuators, and resonators, has led to a growing need to understand their mechanics and mechanical behaviors. In particular, understanding their intrinsic mechanical properties and behaviors as a free-standing membrane becomes crucial when considering 2D materials as a mechanical membrane. However, applying conventional continuum-based mechanics to 2D materials is limited due to their extremely anisotropic dimension (104~106) and atomic-scale thicknesses. In this talk, I will discuss the intrinsic mechanics of 2D materials in the three-dimensional space. Firstly, we measure the out-of-plane bending stiffness 2D materials through the combination of computational and electron microscopy experiments. This study reveals that the van der Waals interfaces are the origin why the continuum bending theory breaks down in 2D materials. Furthermore, the study of wafer-scale, 3-atom-thick 2D material on water surface demonstrates spontaneous strain-driven self-wrinkling, which is controlled by polycrystalline domain size and results in a drastic reduction of in-plane stiffness. Additionally, the friction-free interface between 2D materials and water surface enables the 2D mechanics platform. Overall, these understandings of the mechanics of 2D materials will help the utilization of these materials for next-generation electromechanical applications.
Dr. Jaehyung Yu earned his M.S. and PhD in Mechanical Science and Engineering from UIUC, under the guidance of Professor Arend M. van der Zande and professor Elif Ertekin. He holds a B.S. in Mechanical Engineering from KAIST, Korea. After completing his PhD, he worked as a postdoctoral scholar with Professor Jiwoong Park at the University of Chicago. Dr. Jaehyung will be joining the Mechanical Engineering department of Chung-Ang University (Korea) as an assistant professor in September 2023.
