Recombinant Spider Silk Fiber with High Dimensional Stability in Water and Its NMR Characterization.

Spider dragline silk has unique characteristics of strength and extensibility, including supercontraction. When we use it as a biomaterial or material for textiles, it is important to suppress the effect of water on the fiber by as much as possible in order to maintain dimensional stability. In order to produce spider silk with a highly hydrophobic character, based on the sequence of ADF-3 silk, we produced recombinant silk (RSSP(VLI)) where all QQ sequences were replaced by VL, while single Q was replaced by I.

Top-down preparation of self-supporting supramolecular polymeric membranes using highly selective photocyclic aromatization of cis-cisoid helical poly(phenylacetylene)s in the membrane state.

A novel, highly selective photocyclic aromatization (SCAT) of π-conjugated polymers from phenylacetylene having two hydroxyl groups to exclusively yield a 1,3,5-trisubstituted benzene derivative was developed, and its success was confirmed by (1)H NMR, GPC, and TOF-MS. The SCAT reaction has many unique characteristics. (1) It is a quantitative reaction: it gave only the corresponding cyclic trimer, i.

Pseudo helix-sense-selective polymerisation of achiral substituted acetylenes.

Pseudo helix-sense-selective polymerisation of a wide range of achiral substituted acetylenes having dynamic covalent bonds has been realised to yield static one-handed helical polymers without any other chiral moieties.

Synthesis of stable and soluble one-handed helical homopoly(substituted acetylene)s without the coexistence of any other chiral moieties via two-step polymer reactions in membrane state: molecular design of the starting monomer.

A soluble and stable one-handed helical poly(substituted phenylacetylene) without the coexistence of any other chiral moieties was successfully synthesized by asymmetric-induced polymerization of a chiral monomer followed by two-step polymer reactions in membrane state: (1) removing the chiral groups (desubstitution); and (2) introduction of achiral long alkyl groups at the same position as the desubstitution to enhance the solubility of the resulting one-handed helical polymer (resubstitution). The starting chiral monomer should have four characteristic substituents: (i) a chiral group bonded to an easily hydrolyzed spacer group; (ii) two hydroxyl groups; (iii) a long rigid hydrophobic spacer between the chiral group and the polymerizing group; (iv) a long achiral group near the chiral group. As spacer group a carbonate ester was selected.