Two-step mechanism of rotational relaxation in lamellar phases of rods: accelerating effect of the addition of spheres.
By using computer simulation on a model colloidal rod-sphere mixture in its lamellar phase, the mechanism responsible for the rod rotational relaxation has been definitely identified and characterized. It consists of two steps: first, a rod, parallel to the director, has to escape from the layer in which it is located and go into the interlayer region mostly populated by spheres, perpendicular to the director; then, it has to insinuate again into one of the adjacent layers, with 50% of probability of resulting antiparallel to the director. While this mechanism is also operating in a pure smectic phase of rods, the presence of spheres increases notably its efficacy, thus promoting the rotational relaxation and facilitating its observation.
Cinacchi
Giorgio
G
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, England, United Kingdom. giorgio.cinacchi@bristol.ac.uk
De Gaetani
Luca
L