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Self-assembly provides an attractive route to functional organic materials, with properties and hence performance depending sensitively on the organization of the molecular building blocks (1-5). Molecular organization is a direct consequence of the pathways involved in the supramolecular assembly process, which is more amenable to detailed study when using one-dimensional systems. In the case of protein fibrils, formation and growth have been attributed to complex aggregation pathways (6-8) that go beyond traditional concepts of homogeneous (9-11) and secondary (12-14) nucleation events. The self-assembly of synthetic supramolecular polymers has also been studied and even modulated (15-18), but our quantitative understanding of the processes involved remains limited. Here we report time-resolved observations of the formation of supramolecular polymers from π-conjugated oligomers. Our kinetic experiments show the presence of a kinetically favoured metastable assembly that forms quickly but then transforms into the thermodynamically favoured form. Quantitative insight into the kinetic experiments was obtained from kinetic model calculations, which revealed two parallel and competing pathways leading to assemblies with opposite helicity. These insights prompt us to use a chiral tartaric acid as an auxiliary to change the thermodynamic preference of the assembly process (19). We find that we can force aggregation completely down the kinetically favoured pathway so that, on removal of the auxiliary, we obtain only metastable assemblies., The π-conjugated oligomer S-chiral oligo(p-phenylenevinylene) (SOPV, Fig 1a) serves as a functional material in a variety of organic electronic devices, with performance critically dependent on the material's morphology (20). This [...]

The interaction of as-prepared single-walled carbon nanotubes (SWNTs), containing a mixture of metallic and semiconducting species with the potassium salt of coronene tetracarboxylic acid, in an aqueous medium has given a simple method of separating semiconducting and metallic species. The method avoids centrifugation and is amenable for large-scale separation and interaction with strong electron acceptor molecules brings about metal-semiconductor transitions in SWNTs.

Solid- and liquid-phase strategies are used for synthesizing two oligo(p-phenylenevinylene)-peptide hydride amphiphiles. The studies have shown that the [pi]-conjugated oligo(p-phenylenevinylene) trimer (OPV)-peptide conjugates can be self-assembled in organic and aqueous media as well as at the solid-liquid interface.

The synthesis and characterization of oligo(p-phenylenevinylene) (OPV)-substituted hexaarylbenzene are described. The liquid-solid interface has shown that the star-shaped OPV molecule has formed an organized monolayer having a chiral hexagonal lattice.

The synthesis of chiral (2S)-ethylhexanol for functionalizing and solubilizing conjugated polymers is described. The properties of the two new chiral polymers have differed significantly from those of its methylbutyl analog as examined by chiral aggregation, which has provided insight into the role of interchain interactions in the subsecond switching electrochromic polymers.

The fluorescence resonance energy transfer (FRET) to a suitable acceptor was studied by using supramolecular donor scaffold, which was prepared from self-assembled nanotapes of a few tailor-made oligo(p-phenylenevinylene)s (OPVs). The results indicate that energy transfer occurs exclusively from the self-assembled donor and not directly from the individual donor molecules.

Phenylenevinylen based organogels are described with self-assembled nanostructures achieved from cooperative hydrogen bonding and pi-stacking.