Apparent Softening of Wet Graphene Membranes on a Microfluidic Platform

Autor: 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.
Zdroj: ACS Nano; May 2018, Vol. 12 Issue: 5 p4312-4320, 9p
Abstrakt: 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.
Databáze: Supplemental Index