Fig. 4: Wettability on supported and on suspended monolayer and multilayer graphene.

(circles) Contact angles, CA or θ (deg), of droplets on suspended: 1L^sus, 2 L^sus, 4 L^sus, and ML^sus, and (diamonds) contact angles of droplets on supported: 1L_sup, 2L_sup, 4L_sup, and ML_sup where N refers to the number of layers. For each case, 10 to 20 independent CA measurements are reported. Theoretical CA trend based on the minimum Lennard-Jones (L-J) potential for suspended graphene as in ref. ²⁴ is plotted as a green solid line, while blue dashed line includes theoretical CA calculation of supported graphene on copper (Cu) from ref. ²³, for comparison. ESEM snapshots of (top) droplets on 1L^sus, 2L^sus, 4L^sus and ML^sus samples, and (bottom) droplets on 1L_sup, 2L_sup, 4L_sup and ML_sup samples are also included for comparison. Non-wetting droplets on 1L^sus are represented as red circles. CA measurements of wetting droplets on suspended monolayer graphene supported over a TEM grid with closed holes from (open stars) our work Fig. S8(b) in the accompanying Supplementary Note 3 and (closed stars) the work of Zhang et al.³¹ are included for comparison. Advancing CA (closed triangles) and receding CA (open triangles) of large-area 1L graphene drape from ref. ³² are also included (note that the x-axis representation for suspended monolayer graphene with closed holes is slightly shifted so that the two conditions can be readily identified).