where θ is the angle between the short (unique) particle axis and the z axis, and the average • • • z is over all fluid particles whose centres were in the histogram bin centred at position z. A value of 1 indicates fully face-on alignment, and -1 2 indicates fully sideon. For isotropic orientations, s(z) = 0. Throughout this work, the terms face-on and side-on will be used to describe any orientation that is either predominantly face-on (s(z) > 0) or side-on (s(z) < 0), not just the fully aligned extremes. Representative density and orientation profiles are shown in Fig. , and selected additional profiles are given in the ESI, section S5.