Fig. 1: Water flow through graphite vs. hBN capillaries.
From: Water friction in nanofluidic channels made from two-dimensional crystals
a Schematics of our capillary devices. b Optical image of a hBN capillary device on a silicon nitride membrane (seen in light green). The top hBN layer is contoured with the dotted curve for visibility. Five parallel rectangular holes (light purple color) open to the other side of the wafer. The direction of the channels underneath the top hBN layer is indicated by the red dotted lines with a defined length L. c Weight loss due to water evaporation through four-layer (h ≈ 1.4 nm) capillaries. The hBN device (green circles) has ~1250 (±40) parallel channels and the flow is normalized for channel length of L ∼ 1 µm. The graphite device (grey triangles) has ~15 times fewer channels (n ≈ 80 (±4), average L ≈ 6 µm). The bottom inset shows the weight loss from four different hBN devices normalized per µm channel length. Schematics of water flow measurement setup and the details of monitoring the weight loss of water through the microgravimetry setup are in Supplementary Fig. 2.
