Nucleation in suspensions of colloidal hard rods

The interest in positional and orientational ordered assemblies of anisotropic particles is driven by their great technological potential as they exhibit anisotropic optical properties, but arises also from a more fundamental point of view. A wide variety of techniques has been employed for the self-organization of rod-like particles, such as applied electric fields, substrates that preferentially orient the rods , and by fluid flow direction. Most of the rod particles self-assembly techniques are thus based on the alignment of the rods, which facilitates the formation of self-assembled structures with orientational and/or positional order. Another promising route is to tune the interaction potentials between the rods, e.g. by adding depletants [1], such that one can control the phase behaviour and nucleation of the self-assembled structures. However, both simulations and experiments show that crystal nucleation of attractive rods proceeds via the formation of single membranes of hexagonally ordered rods [1,2]. It was reported that in the suspensions of short hard rods, the crystal nucleation is hampered by particles aligned parallel to the bottom and top surface of the crystallite, i.e., self-poisoning of crystal nuclei[3]. We use molecular dynamics and Monte Carlo simulations to study the kinetic pathways for crystal/smectic nucleation in solutions of short hard rods. Our results show that nucleation is strongly influenced by glassy dynamics.