Janus helices: From fully attractive to hard helices.

The phase diagram of hard helices differs from its hard rods counterpart by the presence of chiral "screw" phases stemming from the characteristic helical shape, in addition to the conventional liquid crystal phases also found for rod-like particles. Using extensive Monte Carlo and Molecular Dynamics simulations, we study the effect of the addition of a short-range attractive tail representing solvent-induced interactions to a fraction of the sites forming the hard helices, ranging from a single-site attraction to fully attractive helices for a specific helical shape. Different temperature regimes exist for different fractions of the attractive sites, as assessed in terms of the relative Boyle temperatures, that are found to be rather insensitive to the specific shape of the helical particle.

The thermodynamic origins of chiral twist in monolayer assemblies of rod-like colloids.

The propagation of chirality across scales is a common but poorly understood phenomenon in soft matter. Here, using computer simulations, we study twisted monolayer assemblies formed by both chiral and achiral rod-like particles in the presence of non-adsorbing polymer and characterise the thermodynamic driving forces responsible for the twisting. We observe assemblies with both like and inverted chirality relative to the rods and show that the preferred twist is already determined during the initial stage of the self-assembly.

Crystal nucleation in colloidal rod suspensions: The effect of depletant size.

In order to better control the assembly of nanorods, knowledge of the pathways by which they form ordered structures is desirable. In this paper, we characterize crystal nucleation in suspensions of spherocylindrical rods with aspect ratio L/D = 2.3 in the presence of both small and large polymer depletants.

Interfacial and bulk nanostructure of liquid polymer nanocomposites.

Liquid polymer nanocomposites (l-PNCs) have been prepared using silica nanoparticles with diameters of 15 nm (l-PNC-15) and 24 nm (l-PNC-24), and Jeffamine M-2070, an amine-terminated ethylene oxide/propylene oxide (PEO/PPO, ratio 31/10) copolymer. Jeffamine M-2070 was used as the host liquid in which the particles were suspended and was also grafted onto the particle surface to prevent aggregation. The grafting density of Jeffamine M-2070 on the particle surfaces was ∼0.