• 文献标题:   Origin of friction hysteresis on monolayer graphene
  • 文献类型:   Article
  • 作  者:   ZHANG DL, ZHANG YG, LI Q, DONG MD
  • 作者关键词:   friction hysteresi, friction force microscopy, graphene, environmental adsorbate, adhesion force
  • 出版物名称:   FRICTION
  • ISSN:   2223-7690 EI 2223-7704
  • 通讯作者地址:  
  • 被引频次:   16
  • DOI:   10.1007/s40544-021-0517-1 EA AUG 2021
  • 出版年:   2022

▎ 摘  要

Load-dependent friction hysteresis is an intriguing phenomenon that occurs in many materials, where the friction measured during unloading is larger than that measured during loading for a given normal load. However, the mechanism underlying this behavior is still not well understood. In this work, temperature-controlled friction force microscopy was utilized to explore the origin of friction hysteresis on exfoliated monolayer graphene. The experimental observations show that environmental adsorbates from ambient air play an important role in the load dependence of friction. Specifically, the existence of environmental adsorbates between the tip and graphene surface gives rise to an enhanced tip-graphene adhesion force, which leads to a positive friction hysteresis where the friction force is larger during unloading than during loading. In contrast to positive friction hysteresis, a negative friction hysteresis where the friction force is smaller during unloading than during loading is observed through the removal of the environmental adsorbates upon in situ annealing. It is proposed that the measured friction hysteresis originates from the hysteresis in the contact area caused by environmental adsorbates between the tip and graphene. These findings provide a revised understanding of the friction hysteresis in monolayer graphene in terms of environmental adsorbates.