Wetting behaviors and applications of metal-catalyzed CVD grown graphene

Metal-catalyzed chemical vapor deposition (CVD) growth of graphene is one of the most important techniques to produce high quality and large area graphene films. Apart from the outstanding electronic and optoelectronic properties of the metal-catalyzed CVD grown graphene, its wetting behavior also possesses great potential that can be exploited for various applications such as water harvesting, micro–nano fluidics, triboelectricity generation, electrowetting, oil–water separation, biomimetics, etc. In this review article, we discuss the most recent advancements in the wetting behavior based applications of the metal-catalyzed CVD grown graphene. The focus is mainly on the metal-catalyzed CVD grown graphene as it offers better control over the growth of graphene films as compared to other techniques. Moreover, only those wetting behavior based applications are discussed where liquid droplet motion and actuation, and its stable hydrophobic/superhydrophobic state on graphene's surface are exploited. The article starts with a brief introduction of graphene, its metal-catalyzed CVD growth, and surface energy. Thereafter, it is mainly divided into two sections, viz., (1) important concepts and results related to liquid wetting behavior on the surface of metal-catalyzed CVD grown graphene and (2) liquid droplet wetting behavior based applications such as omniphobic/hydrophobic/superhydrophobic 3D graphene foam based filters for oil–water–gas separation, biomimetic surfaces for anti-corrosion and droplet transfer applications, water harvesting and defogging, triboelectric nanogenerators, electrowetting-based liquid lenses, and electro-active flow control devices. Finally, conclusions and outlook of this emerging research field are presented. This article aims to provide up-to-date information about the rapidly emerging research area of wetting behavior based applications of metal-catalyzed CVD grown graphene.