Swollen elastomer liquid crystals undergo significant deformations by application of an electric field perpendicular to their alignment axis, as shown in experiments by Urayama et al. [Urayama K, Honda S, Takigawa T (2006) Macromolecules 39:1943-1949]. Here we clarify this surprising effect at the molecular level using large scale Monte Carlo simulations of an off-lattice model based on a soft Gay-Berne potential. We provide the internal change of molecular organization, as well as the key observables during the actuation cycle.
COBISS.SI-ID: 2439012
We investigated the energetic efficiency of low Reynolds number swimmers driven by self-propulsion along their surface. An example of such swimmers are ciliated protozoa, but also artificial chemiphoretic swimmers. It turns out that the cost of propulsion is proportional to the square of the fluid velocity above the surface, integrated over the surface of the swimmer. We thus determined the swimmer shapes and their velocity distribution in a way that they achieve a given swimming velocity with minimum dissipation while keeping the volume constant. The result is surprising as the optimal shape can, depending on the allowed curvature, contain protrusions along the symmetry axis. The calculated optimal swimmer shapes also show a high degree of similarity with various microorganisms found in nature.
COBISS.SI-ID: 26105639
We addressed systems of cholesteric liquid crystal droplets, where the relation between the confinement via the spherical surface of the droplet and the chiral twisting of the liquid crystalline orientational order is specifically expressed. Multiple anisotropic optical profiles are demonstrated, emerging as a result of geometrical confinement. Also, the authors show that changing the intrinsic twisting of the molecular optical axes induces remarkable changes in the droplet structure, modifying optical and photonic properties of the droplets. The demonstrated approach could be used as a possible mechanism to envisage soft matter optic and photonic elements in all-photonics circuits.
COBISS.SI-ID: 2508388
We report the realization of FETs made with chemically synthesized layered 2D crystal semiconductor WS2. The 2D Schottky-barrier FETs demonstrated ambipolar behavior and a high (~105x) on/off ratio at room temperature with current saturation. The behavior was attributed to the presence of an energy bandgap in the 2D crystal material. The FETs show clear photoresponse to visible light. The promising electronic and optical characteristics of the devices combined with the layered 2D crystal flexibility make WS2 attractive for future electronic and optical devices.
COBISS.SI-ID: 26026535
We studied chiral colloidal dimers on theoretical and experimental level. The influence of the chirality on the tangles in the formalism of tetrahedral rotations is of vital importance if the formalism is to be used to predict the possible structures. Systems with sufficiently complex boundary conditions can assume a large number of metastable configurations. Accurate prediction and guided simulation of complex structures can accompany the experimental results for chiral defect systems induced optically, by colloidal inclusions, or by confinement.
COBISS.SI-ID: 2452068