Fluorination of Graphene Enhances Friction Due to Increased Corrugation
详细信息 查看全文
- 作者：Qunyang Li ; Xin-Z. Liu ; Sang-Pil Kim ; Vivek B. Shenoy ; Paul E. Sheehan ; Jeremy T. Robinson ; Robert W. Carpick
- 刊名：Nano Letters
- 出版年：2014
- 出版时间：September 10, 2014
- 年：2014
- 卷：14
- 期：9
- 页码：5212-5217
- 全文大小：278K
- ISSN：1530-6992
文摘
The addition of a single sheet of carbon atoms in the form of graphene can drastically alter friction between a nanoscale probe tip and a surface. Here, for the first time we show that friction can be altered over a wide range by fluorination. Specifically, the friction force between silicon atomic force microscopy tips and monolayer fluorinated graphene can range from 5鈭? times higher than for graphene. While consistent with previous reports, the combined interpretation from our experiments and molecular dynamics simulations allows us to propose a novel mechanism: that the dramatic friction enhancement results from increased corrugation of the interfacial potential due to the strong local charge concentrated at fluorine sites, consistent with the Prandtl-Tomlinson model. The monotonic increase of friction with fluorination in experiments also demonstrates that friction force measurements provide a sensitive local probe of the degree of fluorination. Additionally, we found a transition from ordered to disordered atomic stick鈥搒lip upon fluorination, suggesting that fluorination proceeds in a spatially random manner.