Contact-electrification between two identical materials: Curvature effect

Cheng Xu, Binbin Zhang, Aurelia Chi Wang, Haiyang Zou, Guanlin Liu, Wenbo Ding, Changsheng Wu, Ming Ma, Peizhong Feng, Zhiqun Lin, Zhong Lin Wang

Research output: Contribution to journalArticlepeer-review

123 Scopus citations


It is known that contact-electrification (or triboelectrification) usually occurs between two different materials, which could be explained by several models for different materials systems (Adv. Mater. 2018, 30, 1706790; Adv. Mater. 2018, 30, 1803968). But contact between two pieces of the chemically same material could also result in electrostatic charges, although the charge density is rather low, which is hard to understand from a physics point of view. In this paper, by preparing a contact-separation mode triboelectric nanogenerator using two pieces of an identical material, the direction of charge transfer during contact-electrification is studied regarding its dependence on curvatures of the sample surfaces. For materials such as polytetrafluoroethylene, fluorinated ethylene propylene, Kapton, polyester, and nylon, the positive curvature surfaces are net negatively charged, while the negative curvature surfaces tend to be net positively charged. Further verification of the above-mentioned trends was obtained under vacuum (â1 Pa) and higher temperature (≤358 K) conditions. Based on the received data acquired for gentle contacting cases, we propose a curvature-dependent charge transfer model by introducing curvature-induced energy shifts of the surface states. However, this model is subject to be revised if the mutual contact mode turns into a sliding mode or more complicated hard-pressed contact mode, in which a rigorous contact between the two pieces of the same material could result in nanoscale damage/fracture and possible species transfer. Our study provides a primitive step toward understanding the basics of contact-electrification.

Original languageEnglish
Pages (from-to)2034-2041
Number of pages8
JournalACS Nano
Issue number2
StatePublished - 26 Feb 2019

Bibliographical note

Funding Information:
The authors are grateful for the support received from Hightower Chair Foundation. C.X. thanks the Outstanding Teacher Overseas Research Project of China University of Mining and Technology.

Publisher Copyright:
© 2019 American Chemical Society.


  • Contact-electrification
  • Curvature
  • Identical material
  • Surface states
  • Triboelectric nanogenerator
  • Triboelectrification


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