fig5

Figure 5. Factors that can impact the apparent contact angle measured on the supported 2D material systems. (A) WCAs as a function of exposure time for HOPG and graphene on Cu and Ni substrates^[9]; (B) WCA of a 20-nm-thick InSe on SiO₂ before and after 350 °C thermal annealing^[90]; (C) Schematic of three possible contact modes between a 2D material and a substrate, including non-conformal, partially conformal, and fully conformal; (D) WCA on polydimethylsiloxane-supported graphene as a function of biaxial compressive strain applied to the substrate^[104]; (E) Schematic illustration of the graphene wettability being modulated by doping induced Fermi level shifts^[105]; (F) WCA and surface potential of graphene as functions of the distance from the gold pad in a metal - graphene heterojunction^[105]. Figures are adapted from references^{[9,90,104,105]} with permission. HOPG: Highly oriented pyrolytic graphite; WCA: water contact angle; 2D: two-dimensional.