Ferrari Gustavo A, de Oliveira Alan B, Silvestre Ive, Matos Matheus J S, Batista Ronaldo J C, Fernandes Thales F D, Meireles Leonel M, Eliel Gomes S N, Chacham Helio, Neves Bernardo R A, Lacerda Rodrigo G
Departamento de Física , Universidade Federal de Minas Gerais , Belo Horizonte , Minas Gerais 30123-970 , Brazil.
Campus Ouro Preto , Instituto Federal de Minas Gerais , Ouro Preto , MG 35400-000 , Brazil.
ACS Nano. 2018 May 22;12(5):4312-4320. doi: 10.1021/acsnano.7b08841. Epub 2018 Apr 27.
Graphene is regarded as the toughest two-dimensional material (highest in-plane elastic properties) and, as a consequence, it has been employed/proposed as an ultrathin membrane in a myriad of microfluidic devices. Yet, an experimental investigation of eventual variations on the apparent elastic properties of a suspended graphene membrane in contact with air or water is still missing. In this work, the mechanical response of suspended monolayer graphene membranes on a microfluidic platform is investigated via scanning probe microscopy experiments. A high elastic modulus is measured for the membrane when the platform is filled with air, as expected. However, a significant apparent softening of graphene is observed when water fills the microfluidic system. Through molecular dynamics simulations and a phenomenological model, we associate such softening to a water-induced uncrumpling process of the suspended graphene membrane. This result may bring substantial modifications on the design and operation of microfluidic devices which exploit pressure application on graphene membranes.
石墨烯被视为最坚韧的二维材料（具有最高的面内弹性性能），因此，它已被用作/提议用作众多微流体装置中的超薄膜。然而，对于与空气或水接触的悬浮石墨烯膜的表观弹性性能的最终变化，仍缺乏实验研究。在这项工作中，通过扫描探针显微镜实验研究了微流体平台上悬浮单层石墨烯膜的力学响应。正如预期的那样，当平台充满空气时，测得膜具有高弹性模量。然而，当水充满微流体系统时，观察到石墨烯明显软化。通过分子动力学模拟和唯象模型，我们将这种软化与悬浮石墨烯膜的水诱导展皱过程联系起来。这一结果可能会对利用对石墨烯膜施加压力的微流体装置的设计和操作带来重大改变。
