Mono- and di-(trimethylammonium)-terminated polystyrenes with similar molar masses were synthesized. Bromopolystyrenes were first prepared by atom transfer radical polymerization (ATRP) using (N-Boc-propylamino)-2-bromoisobutyrate as initiator and Cu(I)Br/2,2-bipyridine as catalytic system in bulk at 110 °C. ,-Telechelic polymer with double molecular weight with respect to the starting polystyrene was then obtained under atom transfer radical coupling process using 2,2-bipyridine and copper(0) mediated reductive conditions in anisole. Final (trimethylammonium)-terminated polystyrenes were eventually obtained after removal of the tert-butyloxycarbonyl group and permethylation reactions. Intermediate and final polymers were characterized by 1H NMR. The aligning properties of the obtained polymers for liquid crystals have been investigated. Pretilt and zenithal anchorings on ITO/glass substrates were measured. Finally, the possibility for the telechelic polystyrene to form a network in an inverted microemulsion was also considered.

We studied the Brownian motion of isolated ellipsoidal particles in water confined to two dimensions and elucidated the effects of coupling between rotational and translational motion. By using digital video microscopy, we quantified the crossover from short-time anisotropic to longtime isotropic diffusion and directly measured probability distributions functions for displacements. We confirmed and interpreted our measurements by using Langevin theory and numerical simulations. Our theory and observations provide insights into fundamental diffusive processes, which are potentially useful for understanding transport in membranes and for understanding the motions of anisotropic macromolecules.

We describe the experiments on a magnetically-induced drift of the easy axis on a soft surface of photoaligning material fluoro-polyvinyl-cinnamate. We found unexpected partial relaxation of the drift of the easy axis after switching the magnetic field off. This relaxation cannot be explained in a framework of the existing models and requires additional assumptions about the drift process. We propose a model that explains the experimental data suggesting elastic-like behaviour of the polymer fragments during the drift of the easy axis.

Abstract— The photoaligning properties of the popular photoaligning material polyvinyl-4(fluorocinnamate) (PVCN-F) are presented. The aligning quality and azimuthal and zenithal anchoring energy were measured and the drift of the easy orientation axis (gliding effect) on the PVCN-F surface, depending on UV exposure, was studied. Special attention is paid to unraveling the contribution of the adsorption liquid-crystal molecules onto the aligning surface to the anchoring properties of PVCNF and measuring the drift of the easy orientation axis over the PVCN-F surface. It is shown that a relatively weak azimuthal anchoring energy (Waz ∼ 10−7 − 10−5 J/m2) leads to strong drift of the easy axis in the azimuthal plane that was observed in a moderate (∼0.1–0.3 T) magnetic field. A much stronger polar anchoring (Wzen ∼ 10−4 J/m2) allowed us to observe the essential gliding of the easy axis in the zenithal plane in a rather strong electric field (∼5 V/μm).