“…For hard rectangles of aspect ratio 7, the isotropic-anisotropic transition is predicted to occur at reduced surface densities ρ = σL 2 ≈ 3-5, where σ is the particle surface density, and L is the rod length. [29,34,35] In agreement with the expectations, at relatively high densities (ρ ≈ 2.4), although a certain degree of orientational anisotropy is attained as a result of crowding in the dense ensemble of mica-adsorbed DNA rods, the system still did not undergo a transition into a smectic phase (Figure 2c). Nonetheless, at a reduced surface density of ρ ≈ 2.9, the particles form a quasi-smectic phase, as additionally confirmed by the spatial frequency spectrum (Figure 2d).…”