Mechanical Properties

Prediction of Mechanical Properties of Graphene surfaces on Self-Assembled Monolayers

• 5. 2015 - 2. 2017, Supported by Research Triangle Material Research Science Engineering Center

• This work collaborated with Dr. Stefan Zauscher and his group at Duke University (Durham, NC)

As a researcher majoring in materials science and engineering, I also conducted research on the mechanical properties of graphene surfaces, which are crucial factors for designing the applications in the industry. Self-assembled monolayers (SAMs) have been extensively used to engineer the electronic properties of the substrate supported graphene devices. However, little is known about how the surface chemistry of SAMs affect the interfacial mechanical properties of graphene supported SAMs, which are often overlooked but very important aspects of the fabrication of substrate-supported electronics.

I was involved in this combined computational and experimental work and focused on the computation part to find out the effect of SAM surface chemistry on the mechanical properties. The results from my computational simulations and analyses were the first discovery to provide the important phenomena occurring at the interfacial region between graphene and SAMs: (1) head group chemistry of SAMs can have a significant effect on the out-of-plane elastic modulus of graphene – SAM structure; (2) if SAMs with hydrophilic head groups are used, water molecules gradually migrate into the interfacial region, thus leading to decrease in the mechanical strength. Moreover, by using computation approach, I could precisely predict Young’s modulus (directly related to mechanical strength), which is difficult to measure experimentally due to the nature of the samples. These observations provided the guidance for a better choice of SAMs head group to make substrate-supported electronic more stable and stronger. For this work, I collaborated with Dr. Stefan Zauscher and his group (Dr. Qing Tu and Zehra Parlak) at Duke University (Durham, NC) for the experimental verification of my predictions and to ascertain the mechanisms of important interactions. Recently, we published one high-quality journal paper (see [1] in Journal Paper below).

Journal Paper

[1] Qing Tu, Ho Shin Kim,† Thomas J. Oweida, Zehra Parlak, Yaroslava G. Yingling, and Stefan Zauscher. “Interfacial mechanical properties of graphene on self-assembled monolayers: experiments and simulations”, ACS Applied Materials & Interfaces 9, 11, (2017): 10203-10213, †Co-first author, #Mechanical property estimation of SAM-graphene# (IF: 7.504, Time Cited: 1)

[1] Ho Shin Kim,† Thomas J. Oweida,† and Yaroslava G. Yingling “Interfacial stability of graphene-based surfaces in water and organic solvents”, Journal of Materials Science, Accepted, †Co-first author, #Mechanical property of graphene-based surfaces under various solvents# (IF: 2.599, Time Cited: 0)