A chiral perylene diimide building block has been prepared based on an amine derivative of the amino acid L-phenylalanine. Detailed studies were carried out into the self-assembly behaviour of the material in solution and the solid state using UV/Vis, circular dichroism (CD) and fluorescence spectroscopy. For the charged building block BTPPP, the molecular chirality of the side chains is translated into the chiral supramolecular structure in the form of right-handed helical aggregates in aqueous solution. Temperature-dependent UV/Vis studies of BTPPP in aqueous solution showed that the self-assembly behaviour of this dye can be well described by an isodesmic model in which aggregation occurs to generate short stacks in a reversible manner. Wide-angle X-ray diffraction studies (WXRD) revealed that this material self-organises into aggregates with π–π stacking distances typical for π-conjugated materials. TEM investigations revealed the formation of self-assembled structures of low order and with no expression of chirality evident. Differential scanning calorimetry (DSC) and polarised optical microscopy (POM) were used to investigate the mesophase properties. Optical textures representative of columnar liquid–crystalline phases were observed for solvent-annealed samples of BTPPP. The high solubility, tunable self-assembly and chiral ordering of these materials demonstrate their potential as new molecular building blocks for use in the construction of chiro-optical structures and devices.

A variety of functional nanostructured organic/inorganic hybrid materials from the europium-exchanged derivative of a Preyssler-type polyoxometalate (POM), [EuP₅W₃₀O₁₁₀]¹²⁻, and functional organic surfactants were prepared by the ionic self-assembly (ISA) route. The effect of organic surfactants on the structure, photoluminescent, electrochemical and electrochromic properties of the POM anions was investigated in detail. All obtained hybrid materials are amphotropic, i.e., exhibit both thermotropic and lyotropic liquid-crystalline phase behaviour. Investigations of their photophysical properties have shown that the interactions of the various surfactants with the polyanions influence the coordination environments and site symmetry of Eu³⁺ in different ways. The functional groups in the organic surfactants significantly influence the electrochromic properties and photoluminescence of POMs. Different from normal and pyridine-containing complexes, no photoluminescence and no electrochromism were observed from the ferrocene-containing complexes. This may be explained in view of charge transfer between the POM anion and the ferrocenyl group.

Ionic self-assembled (ISA) surfactant complexes present a facile concept for self-assembly of various functional materials. However, no general scheme has been shown to allow their overall alignment beyond local polydomain-like order. Here we demonstrate that ionic complexes forming a columnar liquid-crystalline phase in bulk can be aligned within polymer blends upon shearing, taken that the matrix polymers have sufficiently high molecular weight. We use an ISA complex of N,N′-bis(ethylenetrimethylammonium)perylenediimide/bis(2-ethylhexyl) phosphate (Pery-BEHP) blended with different molecular weight polystyrenes (PS). Based on X-ray scattering studies and transmission electron microscopy the pure Pery-BEHP complex was found to form a two-dimensional oblique columnar phase where the perylene units stack within the columns. Blending the complex with PS lead to high aspect ratio Pery-BEHP aggregates with lateral dimension in the mesoscale, having internal columnar liquid-crystalline order similar to the pure Pery-BEHP complex. When the Pery-BEHP/PS blend was subjected to a shear flow field, the alignment of perylenes can be achieved but requires sufficiently high molecular weight of the polystyrene matrix. The concept also suggests a simple route for macroscopically aligned nanocomposites with conjugated columnar liquid-crystalline functional additives.

We here report on polymeric solid-state self-assembly leading to organization over six length scales, ranging from the molecular scale up to the macroscopic length scale. We combine several concepts, i.e., rod-like helical and disc-like liquid crystallinity, block copolymer self-assembly, DNA-like interactions to form an ionic polypeptide–nucleotide complex and packing frustration to construct mesoscale fibrils. Ionic complexation of anionic deoxyguanosine monophosphate (dGMP) and triblock coil–rod–coil copolypeptides is used with cationic end blocks and a helical rod-like midblock. The guanines undergo Hoogsteen pairing to form supramolecular discs, they π-stack into columns that self-assemble into hexagonal arrays that are controlled by the end blocks. Packing frustration between the helical rods from the block copolymer midblock and the discotic motif limits the lateral growth of the assembly thus affording mesoscale fibrils, which in turn, form an open fibrillar network. The concepts suggest new rational methodologies to construct structures on multiple length scales in order to tune polymer properties.