Water-Holey-Graphene Interactions: Route to Highly Enhanced Water-Accessible Graphene Surface Area

Holey-graphene (HG) is a particular form of nanoporous graphene consisting of a vertically separated arrangement of multilayers of nanoporous graphene. In this paper, we employ molecular dynamics (MD) simulations to study the force-driven wetting interactions between a water nanodrop and an HG architecture (HGA). We demonstrate that through a controlled interplay of factors such as the dimensions of HGA, the magnitude of the force (F) applied to the liquid drop, the time (t) for which the force is applied, and the nature of the functionalization of graphene holes one can trigger hitherto unknown capillarity-driven imbibition of the water drop inside the HG architecture generating a plethora of novel transient and equilibrium wetting states. The strong physical significance of these novel wetting states get amplified by the fact that several of these states signify an enhancement of the water-accessible graphene surface area r(w,HG). This enhancement is established by noting that the ratio r(w,HG)/r(wG) (where r(w,G) is the graphene-water wetting area for nonporous graphene) may become more than 2. Several sophisticated techniques have been devised to fabricate graphene systems that allow large specific surface area of graphene with respect to its contact with water for a plethora of applications ranging from fabrication of graphene-based ultracapacitors to development of graphite-based heat exchangers. On the contrary, this current article sheds light on an alternative facile route of triggering such enhanced graphene-water contact areas through simple controlled water-HG interactions.