Various conventional reactions in polymer chemistry have been translated to the supramolecular domain, yet it has remained challenging to devise living supramolecular polymerization. To achieve this, self-organization occurring far from thermodynamic equilibrium--ubiquitously observed in nature--must take place. Prion infection is one example that can be observed in biological systems. Here, we present an 'artificial infection' process in which porphyrin-based monomers assemble into nanoparticles, and are then converted into nanofibres in the presence of an aliquot of the nanofibre, which acts as a 'pathogen'. We have investigated the assembly phenomenon using isodesmic and cooperative models and found that it occurs through a delicate interplay of these two aggregation pathways. Using this understanding of the mechanism taking place, we have designed a living supramolecular polymerization of the porphyrin-based monomers. Despite the fact that the polymerization is non-covalent, the reaction kinetics are analogous to that of conventional chain growth polymerization, and the supramolecular polymers were synthesized with controlled length and narrow polydispersity.

The whisker method using anisole solvent was developed for effective production of high-aspectratio poly (3-alkylthiophene) (P3AT) nanofibers, and alkyl chain length dependence on nanofiber formation and their properties were fully investigated. The nanofibers have an anisotropic cross section of 3-4 nm height and 24-27 nm width, which slightly increase with the alkyl chain length, and the aspect ratio reaches 100-1000. The nanofibers consist of more than 10 4 parallel stacks of the extended polymer backbones along the nanofiber long axis and of 2-3 laminated layers of the polymer backbones separated by alkyl side chains. The nanofiber formation originates from quasi-one-dimensional crystallization of P3ATs induced by both an attractive π-π* interaction between polymer backbones and the crystallization of alkyl side chains. Carrier transport properties of a AuCl 3 -doped nanofiber network and single nanofibers, both of which are explained by a quasi-one-dimensional variable-range hopping (VRH) model irrespective of alkyl chain length, indicate that the origin of the random potential that localizes the carriers should be attributed not to the bridges between nanofibers but to some factor involved in a single nanofiber.

Chemical, petrochemical, energy, and environment-related industries strongly require high-performance nanofiltration membranes applicable to organic solvents. To achieve high solvent permeability, filtration membranes must be as thin as possible, while retaining mechanical strength and solvent resistance. Here, we report on the preparation of ultrathin free-standing amorphous carbon membranes with Young's moduli of 90 to 170 gigapascals. The membranes can separate organic dyes at a rate three orders of magnitude greater than that of commercially available membranes. Permeation experiments revealed that the hard carbon layer has hydrophobic pores of ~1 nanometer, which allow the ultrafast viscous permeation of organic solvents through the membrane.