title: Surface stress of graphene layers supported on soft substrate.
abstract: We obtain the surface stress of a single layer and multilayers of graphene supported on silicone substrates by measuring the deformation of the graphene-covered substrates induced by the surface tension of liquid droplets together with the Neumann's triangle concept. We find that the surface stress of the graphene-covered substrate is significant larger than that of the bare substrate, and it increases with increasing graphene layers, and finally reaches a constant value of about 120 mN/m on three and more layers of graphene. This work demonstrates that the apparent surface stress of graphene-substrate systems can be tuned by the substrate and the graphene layers. The surface stress and the tuning effect of the substrate on it may have applications in design and characterization of graphene-based ultra-sensitive sensors and other devices. Moreover, the method may also be used to measure the surface stress of other ultrathin films supported on soft substrates.
authors.affiliation: State Key Laboratory for Turbulence and Complex System, and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Du
authors.affiliation: State Key Laboratory for Turbulence and Complex System, and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China.|Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
authors.forename: Jianyong
authors.initials: J
authors.lastname: Huang
authors.affiliation: State Key Laboratory for Turbulence and Complex System, and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China.|CAPT-HEDPS, and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, China.
authors.forename: Huiling
authors.initials: H
authors.lastname: Duan
authors.affiliation: State Key Laboratory for Turbulence and Complex System, and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China.|Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
authors.forename: Chunyang
authors.initials: C
authors.lastname: Xiong
authors.affiliation: State Key Laboratory for Turbulence and Complex System, and Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China.|CAPT-HEDPS, and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, China.
authors.forename: Jianxiang
authors.initials: J
authors.lastname: Wang