  The effect of short chain grafting on the liquid crystalline (LC) ordering of
nano-crystals is investigated using molecular dynamics simulations of a
coarse-grained grafted nano-rod model. Monodisperse nano-rods, with aspect
ratios typical of cellulose nano-crystals (CNCs) are grafted randomly with
oligomers at different grafting densities. LC ordering depends non-trivially on
grafting density as the effective nano-rod shape and softness is modified.
Ungrafted rods exhibit Nematic and tilted Smectic-C phases. At 25\% grafting,
the addition of a few side chains entirely suppresses Smectic order and instead
a persistent Nematic phase is favoured. Intermediary grafting, around 50\%,
results in a Nematic and the reappearance of tilted Smectic-F phases. Heavier
grafting facilitates direct transitions to either Smectic-I with extreme tilt
(75\%) or an un-tilted Smectic-B (100\%). Such behaviour falls outside of
current hard or soft-rod descriptions of phase-transitions in rod-like LC
systems and points to undiscovered LC behaviour in both shape-purified
grafted/un-grafted CNCs.
