Although increasing the strength of the substrate-fluid interactions will increase both the side-substrate and face-substrate interaction strength, which make equal and opposite contributions to the energetic component of the interface free energy different in eqn (7), the face-substrate interactions are expected to dominate for most cases studied in this work due to two factors. First, the stronger face-face interaction compared with sideside interaction (κ < 1) typical of OSCs leads to the strength of face-substrate interactions increasing more rapidly than that of side-substrate interactions when the substrate-substrate interaction strength is increased isotropically, given the mixing rules for fluid-substrate interactions. Second, for oblate (κ < 1) particle shapes typical of OSCs (all the systems studied in this work), a face-on particle interacts with more substrate particles than a side-on particle, and so the strength of the interaction of a fluid particle with the whole substrate increases more rapidly for face-on particles than for side-on particles when the substratesubstrate interaction strength is increased isotropically, even if the fluid particles have no interaction anisotropy (κ = 1). Overall, while changing the fluid-fluid or fluid-substrate interactions are both plausible ways of influencing the energy, large structural changes would likely be required chemically to significantly change the fluid-fluid interaction anisotropy, which will likely also change the shape anisotropy and bulk phase behaviour of the fluid. It should generally be much simpler to change the nature of the solid substrate.