A mesoporous membrane composed of nanochannels with a uniform diameter has a potential use for precise size-exclusive separation of molecules. Here, we report a novel method to form a hybrid membrane composed of silica-surfactant nanocomposite and a porous alumina membrane, by which size-selective transport of molecules across the membrane becomes possible. The nanocomposite formed inside each columnar alumina pore was an assembly of surfactant-templated silica-nanochannels with a channel diameter of 3.4 nm; the channel direction being predominantly oriented along the wall of the columnar alumina pore. Molecules could be transported across the membrane including the silica-surfactant nanocomposite with a capability of nanometre-order size-exclusive separation. Our proposed membrane system has a potential use not only for separation science, but also catalysis and chip technologies.

From the viewpoint of developing photoresponsive supramolecular systems in microenvironments to exhibit more sophisticated photo-functions even at the macroscopic level, inorganic/organic hybrid compounds based on clay or niobate nanosheets as the microenvironments were prepared, characterized, and examined for their photoreactions. We show here a novel type of artificial muscle model unit having much similarity with that in natural muscle fibrils. Upon photoirradiation, the organic/inorganic hybrid nanosheets reversibly slide horizontally on a giant scale, and the interlayer spaces in the layered hybrid structure shrink and expand vertically. In particular, our layered hybrid molecular system exhibits a macroscopic morphological change on a giant scale (~1500 nm) compared with the molecular size of ~1 nm, based on a reversible sliding mechanism.

We report the enhancement of molecular two-photon absorption (2PA) of a dicationic 2PA chromophore (MPPBT) by confining it in a two-dimensional (2D) nanospace formed in nanolayered silicate clay by the cation exchange method in a water-dimethyl sulfoxide mixture. The 2PA property of the MPPBT/silicate nanocomposite prepared from the mixture by casting is characterized by the femtosecond open-aperture Z-scan method. We found that the 2PA cross-section of the chromophore in the nanocomposite is enhanced by a few times that of the dimethylsulfoxide solution at all wavelengths employed. This enhancement is accompanied by a bathochromic shift of the 2PA peak. The origin of this enhancement is discussed in terms of low dimensionality, suppressed internal twisting motion of the chromophore in the 2D confined space, and ionic interactions with the silicate surfaces.