ABSTRACT
We find the structure of a model discotic liquid crystal (DLC) confined between symmetric walls of controllable penetrability. The model consists of oblate hard Gaussian overlap (HGO) particles. Particle-substrate interactions are modelled as follows: each substrate sees a particle as a disc of zero thickness and diameter less than or equal to that of the actual particle,
, embedded inside the particle and located halfway along, and perpendicular to, its minor axis. This allows us to control the anchoring properties of the substrates, from planar (edge-on) for
to homeotropic (face-on) for
. This system is investigated using both Monte Carlo simulation and density-functional theory, the latter implemented at the level of Onsager’s second-virial approximation with Parsons-Lee rescaling. We find that the agreement between theory and simulation is substantially less good than for prolate HGOs; in particular, the crossover from edge-on to face-on alignment is predicted by theory to occur at
, but simulation finds it for
. These discrepancies are likely a consequence of the fact that Onsager’s theory is less accurate for discs than for rods. We quantify this by computing the bulk isotropic-nematic phase diagram of oblate HGOs.
GRAPHICAL ABSTRACT
![](/cms/asset/ebb8ff36-c2ff-4872-835b-7299c88c5ea4/tlct_a_1765424_uf0001_oc.jpg)
Disclosure statement
No potential conflict of interest was reported by the author(s).