Grafting heteroelement-rich groups on graphene oxide: Tuning polarity and molecular interaction with bio-ionic liquid for enhanced lubrication.
Two different heteroelement-rich molecules have been successfully grafted on graphene oxide (GO) sheets which were then used as lubricant additives in bio-ionic liquid. The grafting was processed with reactions between GO sheets and synthesized heteroelement-rich molecules (Imidazol-1-yl phosphonic dichloride and 1H-1,2,4-triazol-1-yl phosphonic dichloride, respectively). The modified GO (m-GO) was added into [Choline][Proline] ([CH][P]) bio-ionic liquid, and has been demonstrated effective additive in promoting lubrication. Different characterization techniques have been utilized to study the reaction between GO and the two modifiers. The effect of molecular structure of the modifiers on the rheological and tribological properties of m-GO/[CH][P] lubricants was systematically investigated. Both theoretical calculation and experimental results demonstrated that the introduced heteroelement-rich groups are beneficial to increase the robustness of lubrication film by intensified hydrogen bonding and enhance the lubricant/friction surface adhesion by increased polarity of the m-GO. As a result, the interfacial lubrication could be significantly improved by these newly developed m-GO/[CH][P] lubricants.
Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States; Division of Machine Elements, Luleå University of Technology, Luleå 97187, Sweden.
Liwen
L
Mu
Division of Machine Elements, Luleå University of Technology, Luleå 97187, Sweden. Electronic address: yijun.shi@ltu.se.
Yijun
Y
Shi
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, PR China.
Xiaojing
X
Guo
College of Biotechnology and Pharmaceutical Engineering, National Engineering Technique Research Center for Biotechnology, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing 211816, PR China.
Wei
W
Zhuang
Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States.
Long
L
Chen
Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States.
Tuo
T
Ji
Division of Machine Elements, Luleå University of Technology, Luleå 97187, Sweden.
Jing
J
Hua
College of Chemistry and Chemical Engineering, Northeast Petroleum University, Daqing 163318, PR China.
Huaiyuan
H
Wang
Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States. Electronic address: jzhu1@uakron.edu.
Jiahua
J
Zhu
Graphene oxide; Hetero-element; Hydrogen bonding; Ionic liquids; Lubrication