To mimic the scaling of molecular mass with molecular size typical of OSCs, the particle mass m was scaled in proportion to the particle volume v f = πσ F σ 2 S /6 (calculated as the volume for an ellipsoid with principal diameters σ F , σ S , and σ S ) to give a constant mass density within the particle. Although approximate, this behaviour is reasonably representative of real systems, for which the mass density within the particle generally varies between 1.4 and 1.7 g/mol/Å 3 when the particle volume is calculated from published biaxial GB parameters (ESI Table ). To facilitate comparison between systems with different sized particles, we have analysed results in terms of the volume fraction, φ , rather than the number density, ρ b , in the bulk fluid. The two are related as