Takuzo Aida

Supramolecular polymers can be random and entangled coils with the mechanical properties of plastics and elastomers, but with great capacity for processability, recycling, and self-healing due to their reversible monomer-to-polymer transitions. At the other extreme, supramolecular polymers can be formed by self-assembly among designed subunits to yield shape-persistent and highly ordered filaments. The use of strong and directional interactions among molecular subunits can achieve not only rich

Expanding the range of healable materials is an important challenge for sustainable societies. Noncrystalline, high-molecular-weight polymers generally form mechanically robust materials, which, however, are difficult to repair once they are fractured. This is because their polymer chains are heavily entangled and diffuse too sluggishly to unite fractured surfaces within reasonable time scales. Here we report that low-molecular-weight polymers, when cross-linked by dense hydrogen bonds, yield me

Over the past decade, major progress in supramolecular polymerization has had a substantial effect on the design of functional soft materials. However, despite recent advances, most studies are still based on a preconceived notion that supramolecular polymerization follows a step-growth mechanism, which precludes control over chain length, sequence, and stereochemical structure. Here we report the realization of chain-growth polymerization by designing metastable monomers with a shape-promoted i

Crystalline nanofibers of linear polyethylene with an ultrahigh molecular weight (6,200,000) and a diameter of 30 to 50 nanometers were formed by the polymerization of ethylene with mesoporous silica fiber-supported titanocene, with methylalumoxane as a cocatalyst. Small-angle x-ray scattering analysis indicated that the polyethylene fibers consist predominantly of extended-chain crystals. This observation indicates a potential utility of the honeycomb-like porous framework as an extruder for na

Owing to their water-rich structures, which are similar to those of biological tissues, hydrogels have long been regarded as promising scaffolds for artificial tissues and organs. However, in terms of the structural anisotropy, most synthetic hydrogels are substantially different from biological systems. Synthetic hydrogels are usually composed of randomly oriented three-dimensional polymer networks whereas biological systems adopt anisotropic structures with hierarchically integrated building u

ADVERTISEMENT RETURN TO ISSUEPREVArticleMetalloporphyrins as Initiators for Living and Immortal PolymerizationsTakuzo AidaTakuzo AidaDepartment of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, JapanMore by Takuzo Aida and Shohei Inoue*Shohei InoueDepartment of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan In papers with more than one author, the asterisk

This paper is a tutorial review of the host-guest chemistry of fullerenes and metalloporphyrin. Among various host molecules for fullerenes, cyclic hosts composed of metalloporphyrin moieties possess one of the highest affinities toward fullerenes, which can be widely tuned simply by changing the central metal ions of the porphyrin moieties. Inclusion of fullerenes occurs not only by van der Waals interactions but also, in some cases, via pi-electronic charge-transfer from the host metalloporphy

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTActivation of carbon dioxide with aluminum porphyrin and reaction with epoxide. Studies on (tetraphenylporphinato)aluminum alkoxide having a long oxyalkylene chain as the alkoxide groupTakuzo Aida and Shohei InoueCite this: J. Am. Chem. Soc. 1983, 105, 5, 1304–1309Publication Date (Print):March 1, 1983Publication History Published online1 May 2002Published inissue 1 March 1983https://pubs.acs.org/doi/10.1021/ja00343a038https://doi.org/10.1021/ja00343a0

Ionic liquids allow millimeter-long single-walled carbon nanotubes to associate tightly, forming a free-standing sheet with superb mechanical and electrical properties. An actuator strip, fabricated by sandwiching an ionic-liquid-gel electrolyte layer with the nanotubes sheets obtained exhibits a large deformation in quick response (4 mm per 0.05 s) to low applied voltages, and a high durability upon 10 000 times continuous operations. Detailed facts of importance to specialist readers are publi

Ferroelectric liquid crystals are materials that have a remnant and electrically invertible polar order. Columnar liquid crystals with a ferroelectric nature have potential use in ultrahigh-density memory devices, if electrical polarization occurs along the columnar axis. However, columnar liquid crystals having an axial nonzero polarization at zero electric field and its electrical invertibility have not been demonstrated. Here, we report a ferroelectric response for a columnar liquid crystal a

Abstract Since the first polymers were discovered, scientists have debated their structures. Before Hermann Staudinger published the brilliant concept of macromolecules, polymer properties were generally believed to be based on the colloidal aggregation of small particles or molecules. From 1920 onwards, polymers and macromolecules are synonymous with each other; i. e. materials made by many covalent bonds connecting monomers in 2 or 3 dimensions. Although supramolecular interactions between mac