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T-shaped polyphilic triblock molecules, consisting of a rodlike p-terphenyl unit, a hydrophilic and flexible laterally attached oligo(oxyethylene) chain terminated by an 1-acylamino-1-deoxy-D-sorbitol unit, and two end-attached lipophilic alkyl chains, have been synthesized by palladium-catalyzed cross-coupling reactions as the key steps. The thermotropic liquid crystalline behavior of these compounds was investigated by polarized light microscopy, differential scanning calorimetry (DSC), and X-ray scattering. We investigated the mode of self-organization as a function of the length and position of the lateral polar chain and the length of the terminal alkyl chains. Depending on the size of the polar and lipophilic segments, a series of unusual liquid crystalline phases was detected. In three of these phases, the space is divided into three distinct periodic subspaces. In addition to a hexagonal channeled layer phase (ChL(hex)) consisting of layers that are penetrated by polar columns, there are also two honeycomb-like network structures formed by square (Col(squ)/p4mm) or pentagonal cylinders (Col(squ)/p4gm). The cylinder walls consist of the terphenyl units fused by columns of alkyl chains, and the interior contains the polar side chains. In addition, a hexagonal columnar phase was observed in which the polar columns are organized in a continuum of terphenyls and alkyl chains with an organization of the terphenyl cores tangentially around the columns with the long axis perpendicular to the columns. For one compound, a reversal of birefringence was observed, which is explained by a reorientation of the terphenyl cores. The addition of protic solvents induces lamellar phases.

Soft matter such as surfactant-water systems, block copolymers or liquid crystals can form periodic structures on nanometre to micrometre scales. This property can be used for templating nanoporous ceramics, surface patterning for electronic devices, or generation of photonic materials. Much attention has been paid to structures appearing between the layer and cylinder phases, the three so-called bicontinuous cubic phases. These are formed by two continuous interpenetrating networks of channels. In this article we describe a related phase, which has the first reported structure consisting of three interpenetrating infinite networks. It is a thermotropic (solvent-free) liquid crystal of cubic symmetry Im3m. The structure is one of the most complex in liquid crystals, and is determined by direct Fourier reconstruction of electron density. We discuss the possible rationale for the existence of such a phase, its structural relationship with the bicontinuous phases, and its position in the phase diagram.

T-shaped molecules are designed in such a way that they self-organize into nanoscale liquid crystalline honeycombs based on polygons with any chosen number of sides. One of the phases reported here is a periodic organization of identical pentagonal cylinders; the other one is a structure composed of square-shaped and triangular cylinders in the ratio 2:1. These two different packing motifs represent duals of the same topological class. The generalization of the concept applied here allows the prediction of a whole range of unusual complex liquid crystalline phases.

The amphiphilic polymers poly[2,5,8,11,14-pentaoxapentadecamethylene(5-hexadecyloxy-1,3-phenylene)] I (abbrev. C16O5), its homologues C16On, n = 1-4, and its copolymers with C16O1 have been synthesised by two Williamson procedures. Method X gives polyether-esters; method Y gives pure polyethers. DSC, optical microscopy, small-to-wide angle X-ray diffraction and complex impedance spectroscopy have been used to investigate organisation and ionic conductivities of the C16On and the C16O5-C16O1 copolymer series and their complexes with LiClO4 and LiBF4. Four-component mixtures of the latter systems (polymers I) with polyoxytetramethylene-decamethylene copolymer (II) and an octadecyl-terminated ABA block copolymer (III) (interfacial stabiliser) ('type D' systems) gave high ambient conductivities ( > or = 10(-4) S cm(-1)) with low temperature dependence. Highest conductivities (8 x 10(-4) S cm(-1) at 20 degrees C) were observed with a type D system based upon C12C18O5X.

A large number of synthetic and natural compounds self-organize into bulk phases exhibiting periodicities on the 10(-8)-10(-6) metre scale as a consequence of their molecular shape, degree of amphiphilic character and, often, the presence of additional non-covalent interactions. Such phases are found in lyotropic systems (for example, lipid-water, soap-water), in a range of block copolymers and in thermotropic (solvent-free) liquid crystals. The resulting periodicity can be one-dimensional (lamellar phases), two-dimensional (columnar phases) or three dimensional ('micellar' or 'bicontinuous' phases). All such two- and three-dimensional structures identified to date obey the rules of crystallography and their symmetry can be described, respectively, by one of the 17 plane groups or 230 space groups. The 'micellar' phases have crystallographic counterparts in transition-metal alloys, where just one metal atom is equivalent to a 10(3)-10(4)-atom micelle. However, some metal alloys are known to defy the rules of crystallography and form so-called quasicrystals, which have rotational symmetry other than the allowed two-, three-, four- or six-fold symmetry. Here we show that such quasiperiodic structures can also exist in the scaled-up micellar phases, representing a new mode of organization in soft matter.

Self-organized supramolecular organic nanostructures have potential applications that include molecular electronics, photonics, and precursors for nanoporous catalysts. Accordingly, understanding how self-assembly is controlled by molecular architecture will enable the design of increasingly complex structures. We report a liquid crystal (LC) phase with a tetragonal three-dimensional unit cell containing 30 globular supramolecular dendrimers, each of which is self-assembled from 12 dendron (tree-like) molecules, for the compounds described here. The present structure is one of the most complex LC phases yet discovered. A model explaining how spatial arrangement of self-assembled dendritic aggregates depends on molecular architecture and temperature is proposed.