Polymer Adsorption on Graphite and CVD Graphene Surfaces Studied by Surface-Specific Vibrational Spectroscopy

Yudan Su; Hui-Ling Han; Qun Cai; Qiong Wu; Mingxiu Xie; Daoyong Chen; Baisong Geng; Yuanbo Zhang; Feng Wang; Y R Shen; Chuanshan Tian

doi:10.1021/acs.nanolett.5b02025

Polymer Adsorption on Graphite and CVD Graphene Surfaces Studied by Surface-Specific Vibrational Spectroscopy

Nano Lett. 2015 Oct 14;15(10):6501-5. doi: 10.1021/acs.nanolett.5b02025. Epub 2015 Sep 21.

Authors

Yudan Su^{1

2}, Hui-Ling Han³, Qun Cai¹, Qiong Wu^{1

2}, Mingxiu Xie⁴, Daoyong Chen⁴, Baisong Geng^{3

5}, Yuanbo Zhang^{1

2}, Feng Wang³, Y R Shen^{1

3}, Chuanshan Tian^{1

2}

Affiliations

¹ State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China.
² Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China.
³ Department of Physics, University of California , Berkeley, California 94720, United States.
⁴ State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University , Shanghai 200433, China.
⁵ School of Physical Science and Technology, Lanzhou University , Lanzhou 730000, China.

PMID: 26367247
DOI: 10.1021/acs.nanolett.5b02025

Abstract

Sum-frequency vibrational spectroscopy was employed to probe polymer contaminants on chemical vapor deposition (CVD) graphene and to study alkane and polyethylene (PE) adsorption on graphite. In comparing the spectra from the two surfaces, it was found that the contaminants on CVD graphene must be long-chain alkane or PE-like molecules. PE adsorption from solution on the honeycomb surface results in a self-assembled ordered monolayer with the C-C skeleton plane perpendicular to the surface and an adsorption free energy of ∼42 kJ/mol for PE(H(CH2CH2)nH) with n ≈ 60. Such large adsorption energy is responsible for the easy contamination of CVD graphene by impurity in the polymer during standard transfer processes. Contamination can be minimized with the use of purified polymers free of PE-like impurities.

Keywords: CVD graphene; graphite; self-assembled alkane; sum frequency vibrational spectroscopy; surface residue; surface structure.

Publication types

Research Support, Non-U.S. Gov't