The report elucidates for the first time a significant effect of a strong magnetic field combined with thermal treatment on the texture of thin liquid-crystalline films in a smectic state. The metastable texture generated in the magnetic field was arrested via the crystallization of mesogens while they cooled to room temperature. The effect was demonstrated on a series of wedge-shaped amphiphilic mesogens based on 1,2,3-tris-(dodecyloxy)benzene (TDOB): asymmetric 2,3,4-tris-(dodecyloxy)benzenesulfonic acid (TDOBSH) and its sodium (TDOBSNa) and pyridine (TDOBSPyr) salts. The thermotropic properties and the structure of the liquid crystal phases of the synthesized compounds were studied using differential scanning calorimetry, polarized optical microscopy and X-ray diffraction. It was shown that, depending on the type of counterion, the synthesized mesogens formed different supramolecular structures. The largest effect of the intense magnetic field was observed for the pyridine salt for which an ordered primitive cubic phase texture was generated upon the normal application of the magnetic field with respect to the film. In contrast, for the corresponding acid, an improvement of the gyroid cubic phase orientation was detected with the magnetic field oriented along the film. A highly ordered columnar phase of the sodium salt was affected only minimally by the magnetic field.

We report on formation of a bicontinuous double gyroid phase by a wedge-shaped amphiphilic mesogen, pyridinium 4′-[3″,4″,5″-tris-(octyloxy)benzoyloxy]azobenzene-4-sulfonate. It is found that this compound can self-organize in zeolite-like structures adaptive to environmental conditions (e.g., temperature, humidity, solvent vapors). Depending on the type of the phase, the structure contains 1D, 2D, or 3D networks of nanometer-sized ion channels. Of particular interest are bicontinuous phases, such as the double gyroid phase, as they hold promise for applications in separation and energy. Specially designed environmental cells compatible with grazing-incidence X-ray scattering and atomic force microscopy enable simultaneous measurements of structural parameters/morphology during vapor-annealing treatment at different temperatures. Such in-situ approach allows finding the environmental conditions at which the double gyroid phase can be formed and provide insights on the supramolecular structure of thin films at different spatial levels.

Annotation The X-ray analysis of a virgin particle taken directly from the synthesis products of an ultra-high molecular weight polyethylene (UHMWPE) and not subjected to any external stresses was carried out using nanofocus beamline ID13 European Synchrotron Radiation Facility (ESRF, Grenoble,France). In the X-ray diffraction curves obtained by scanning an arbitrarily selected portion of a particle with a size of (100 x 20) μm2 by a microbeam (0.3 x 0.3) μm2 with a step of 2 μm horizontally and 0.5 μm vertically, along with reflections from the orthorhombic phase, reflexes from the metastable monoclinic phase were observed. It is believed that the cause of its occurrence may be stresses that develop during specific structure formation in slurry synthesis and persist when cooled to room temperature and the solvent evaporates. The possibility of localization of the monoclinic phase in various morphological formations is discussed.

Phase behavior and supramolecular structure stability of wedge-shaped mesogens at negative temperature have been studied for the first time. The effect of geometrical confinement on water crystallization in different channels was examined. The role of local ordering of linear alkyl groups on stability of the nanochannels during water freezing was enlighten.

The chain conformation of poly(2-vinylpyridine) (P2VP) complexed by 4-((4-4((3,4,5-tris(dodecyloxy)benzoyl) oxy)phenyl)diazenyl)benzenesulfonic acid at different degrees of neutralization (DN) was addressed by small-and wide-angle neutron scattering technique. To get information on the conformation of P2VP chains spatially confined within lamellar and columnar mesophases at different DNs, the complexes were prepared from a blend of protonated and deuterated P2VP. The 2D scattering patterns of extruded fibers show that at low DN the complex self-organizes in a lamellar phase. The inertial mean distances in the direction parallel and perpendicular to the fiber axis reveal the formation of compact disc-like globules of individual P2VP chains at DN = 25 and 33%. With the increase of DN the interaction between the neighboring side groups along the backbone increases. This results in formation of hexagonal columnar phase at DN = 50%, in which the P2VP macromolecules are confined within cylindrical channels forming most probably a disordered helical conformation. At DN = 1.0, the enhanced rigidity of the complex hinders the accommodation of the ligands at the interface with polymer chain. This results in appearance of non-bonded side groups in the columns giving rise to a poorly-ordered structure. In contrast to more rigid chains of poly(4-vinylpyridine), the transition from lamellar to columnar mesophase in P2VP occurs at lower DNs, indicating a significant role of the chain flexibility in the formation of ordered structures.

In this work, a series of aliphatic biodegradable poly(ester amide amide) polymers was synthesized by melt polycondensation of a tailor-made amide-containing monomer based on 1,4-diaminobutane and ε-caprolactone and different dicarboxylic acid methyl esters with even number of methylene groups. The synthesized polymers were characterized by 1H NMR, FT-IR spectroscopy, GPC, SAXS and WAXS. DSC results show that the melting point is located at about 150 °C for all polymers. X-ray scattering experiments in small and wide angles reveal formation of crystals with extended-chain conformation resulting in strict periodicity of electron density along the main chain. TGA data indicate the high thermal stability of polymers to temperatures above 350 °C, which are much above the melting point. The obtained characteristics of the newly synthesized PEAAs can open new perspectives for melt processing to fabricate films, highly oriented fibers and injection-molded parts with good thermal stability and mechanical performance.

We report on the phase behaviour of a wedge-shaped mesogen, which can exist in two different states at room temperature, a stable columnar and a metastable cubic gyroid phase. The latter reveals exceptional stability and remarkable water sorption capacity accounted for by the locally-ordered peripheral alkyl chains.

In supramolecular assemblies, absorption of water can assist the channel formation, similarly to biological systems and Nafion-like commercial ion-selective membranes. In this work, we investigate humidity-induced formation of water channels in wedge-shaped amphiphilic molecules, namely sodium 4'-[3'',4'',5''-tris(alkyloxy)benzoyloxy]azobenzene-4-sulfonates. The studied molecules contain a polar sulfonate group at the tip and a hydrophobic periphery composed of alkyl chains of two different lengths. Upon increasing the relative humidity (RH) the amount of absorbed water significantly increases for the mesogen with dodecyl chains as compared to the one with octyl groups. In the former case, water sorption is accompanied by a considerable enhancement of ionic conductivity and a phase transition. In particular, an increase of RH induces a transition from a lamellar to a columnar phase resulting in the formation of 1D water channels running along the axis of the supramolecular columns. For the compound with shorter alkyl chains the lamellar phase exists in the entire RH-range exhibiting pronounced swelling at high RH-values and thereby forming a 2D water channel structure. NMR diffusometry was used to address the different molecular motions in the lyotropic mesophases of the studied amphiphiles.

Supramolecular self-assembly is a convenient tool for fine-tuning of thin-film structure and properties through adjustment of intermolecular interactions. Designing an appropriate chemical structure together with selecting an optimal sample preparation protocol allows organizing wedge-shaped supramolecular building blocks in various mesophases with 1D-, 2D- or 3D-ordered systems of ion-conducting channels. The control of the topology of ion channels is crucial for the development of next-generation ion conductors. Here we study an amphiphilic wedge-shaped molecule bearing a sulfonate group at the extremity of a bulky aromatic moiety and having a pyridinium counter-ion. This compound exhibits complex structural transitions as a function of temperature and under the action of solvent vapors. The evolution of the thin-film structure was explored in situ by combination of polarizing optical microscopy and grazing-incidence small-angle X-ray scattering. In vapors of alcohols at room temperature, the thin films reveal reversible monoclinic columnar-to-lamellar phase transition. During heating in the swollen state, the films transform to a gyroid phase with 3D bicontinuous networks of ion channels. In the presence of solvent vapors, the opposite transition to lamellar phase takes place at room temperature. Upon this treatment, the gyroid phase is stable over a wide temperature range, which opens a way to fabricate efficient ion conducting materials.

The wedge-shaped amphiphiles bearing sulfonate groups at the tip of the wedge are prone to form ion nano-channels upon exposure to a humid atmosphere. During swelling, water molecules preferentially accumulate in polar regions of the system resulting in the formation of a lyotropic phase. In this work, the details of the structure formation processes occurring upon swelling in water vapour, including determination of the size and topology of the ion nano-channels, are explored. The electron density profiles across the channel are obtained from the fits of the X-ray scattering data with two- and three-phase structural models the applicability of which is critically analysed. The results show that the ion channel size correlates not only with water uptake but also with the molecular architecture such as the structure of the rigid molecular fragment bearing a polar group. These findings can help optimising the ion transport for development of ion-selective membranes.

In present work a new setup for in situ studies of molecular self-assembling process for fabrication of ion-conducting membranes for “green” fuel cells was developed. Due to compactness, this unique setup can be used on the synchrotron beamlines. The GISAXS and optical microscopy data have shown the effectiveness of the control of molecular architecture by impact of high temperature, UV-irradiation and solvent vapors.