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

详细信息    查看全文

• 作者：Yudan Su ; Hui-Ling Han ; Qun Cai ; Qiong Wu ; Mingxiu Xie ; Daoyong Chen ; Baisong Geng ; Yuanbo Zhang ; Feng Wang ; Y. R. Shen ; Chuanshan Tian
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：October 14, 2015
• 年：2015
• 卷：15
• 期：10
• 页码：6501-6505
• 全文大小：418K
• ISSN：1530-6992

文摘

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鈥揅 skeleton plane perpendicular to the surface and an adsorption free energy of 鈭?2 kJ/mol for PE(H(CH₂CH₂)_nH) with n 鈮?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.