DNA Origami Nano-Sheets and Nano-Rods Alter the Orientational Order in a Lyotropic Chromonic Liquid Crystal

Rod-like and sheet-like nano-particles made of desoxyribonucleic acid (DNA) fabricated by the DNA origami method (base sequence-controlled self-organized folding of DNA) are dispersed in a lyotropic chromonic liquid crystal made of an aqueous solution of disodium cromoglycate. The respective liquid crystalline nanodispersions are doped with a dichroic fluorescent dye and their orientational order parameter is studied by means of polarized fluorescence spectroscopy. The presence of the nano-particles is found to slightly reduce the orientational order parameter of the nematic mesophase. Nano-rods with a large length/width ratio tend to preserve the orientational order, while more compact stiff nano-rods and especially nano-sheets reduce the order parameter to a larger extent. In spite of the difference between the sizes of the DNA nano-particles and the rod-like columnar aggregates forming the liquid crystal, a similarity between the shapes of the former and the latter seems to be better compatible with the orientational order of the liquid crystal.

On the separation of time scales close to a glass transition: results from quench studies of the next-nearest-neighbour Ising model

Simulated quench studies of the next-nearest-neighbour (nnn) Ising model demonstrate the separation of time scales corresponding to the order parameter of the ground states and to the orientational order parameter as the value of the nnn interaction parameter approaches the critical value at which the glass transition occurs. Simply defined characteristic times, corresponding to both short-time processes (fast dynamics) and long-time processes (slow dynamics), are used to illustrate this separation and to elucidate the nature of the glass transition for this model. In particular, it is shown that the orientational order parameter remains nonzero at low temperature even at the critical value of the nnn interaction parameter (i.e., for K = Kc). Implications for the study of nonequilibrium effects in systems with striped ground states are discussed.

Deuteron NMR investigation on orientational order parameter in polymer dispersed liquid crystal elastomers

Orientational order parameter of magnetically aligned liquid crystal elastomer particles suspended in a cured silicone matrix is assessed using 2H-NMR spectroscopy. Obtained results correspond well with the composite's thermomechanical response.

Enhanced sampling of cylindrical microphase separation via a shell-averaged bond-orientational order parameter

The underlying free energy surfaces for the order–disorder transition of hexagonal mesophase were identified along with the metstable state.