x y z y ) hematite-PAO4 interactions. Snapshots rendered using VMD. Iron atoms are represented in orange, oxygen are red, carbon is cyan, and hydrogen is white. (g) Through-film temperature profiles of the α-Fe 2 O 3 surface (orange markers), water films (red markers) and PAO4 fluid (cyan markers). The red and blue shaded regions represent the positions of the hot and cold thermostats, respectively.