Kazuyoshi Kanamori

Monolithic Electrode for Electric Double-Layer Capacitors Based on Macro/Meso/Microporous S-Containing Activated Carbon with High Surface Area

Macro/meso/microporous carbon monoliths doped with sulfur have been prepared from sulfonated poly(divinylbenzene) networks followed by the activation with CO2 resulted in the activated carbon monoliths with high surface area of 2400 m2 g−1. The monolithic electrode of the activated carbon shows remarkably high specific capacitance (175 F g−1 at 5 mV s−1 and 206 F g−1 at 0.5 A g−1).

Organic–inorganic hybrid poly(silsesquioxane) monoliths with controlled macro- and mesopores

Siloxane-based organic–inorganic hybrid monoliths with well-defined macropores and/or mesopores have been synthesized by a sol–gel process, accompanied by polymerization-induced phase separation. Using aklyltrialkoxysilanes and alkylene-bridged alkoxysilanes, two different categories of organosiloxane networks have been characterized in view of macroporosity (based on phase separation) and mesoporosity (supramolecularly templated by surfactants). While the alkyl-terminated poly(siloxane) networks exhibit substantial surface hydrophobicity accompanied by mechanical flexibility, the alkylene-bridged networks behave much more similarly to those prepared from tetraalkoxysilanes with regard to surface hydrophilicity, mechanical rigidness and mesopore-forming ability. The supramolecular templating of mesopores embedded in the gel skeletons (which comprise well-defined macroporous networks) has proven to give a wide variety of hierarchically-designed macro–mesoporous hybrid materials.

A Superamphiphobic Macroporous Silicone Monolith with Marshmallow‐like Flexibility

A number of research groups have been studying the preparation of hydrophobic and oleophobic surfaces, both for pure scientific interest and industrial applications. These studies are drawing increasing attention because of the growing demands for applications such as anti-fingerprint touch panels on electronic devices and solar panels that can prevent output fall from dust and smears on the surface by the self-cleaning effect. In nature, many examples of superhydrophobic surface exist with a water contact angle of more than 1508, such as eyes of mosquitos and lotus leaves, 2] and these are important for their survival. Their non-wetting surfaces possess a combination of nanoor microscaled roughness and low surface energy, which are known for the key of creating artificial superhydrophobic surfaces. However, most of the superhydrophobic materials can easily be wetted by organic liquids because of the lower surface tension of the liquids. In recent years, techniques for creating oleophobic surfaces have been vigorously investigated. A promising way to obtain a surface with a contact angle of more than 1508 for organic liquids is to make rough microstructures covered with perfluoroalkyl groups, which are bound on some kinds of polyhedral oligomeric silsesquioxanes (POSS), monomeric silanes, and polymers. However, the reported technologies to achieve superamphiphobicity are limited in the forms of films and fibers. As far as we know, there have been no reports on monolithic superamphiphobic materials that can be prepared in a wide range of thickness and in any shapes. We have been recently investigating marshmallow-like gels derived from triand difunctional alkoxysilanes as coprecursors through a facile one-pot sol–gel reaction. These silicone-based macroporous materials have high porosity (> 90%), flexibility both for compression and bending, and built-in superhydrophobicity. The marshmallow-like gels can be used like a sponge for quick removal of organic liquids/oils from oil–water mixtures for environmental purposes and for new solid-phase extraction media in analytical chemistry. By changing the combination of the alkoxysilanes, various kinds of marshmallow-like gels with different functional groups can be obtained. For example, in the case of methyltrimethoxysilane-dimethyldimethoxysilane copolymer system, the obtained gels are composed of the cross-linked polydimethylsiloxane (PDMS)-like molecular structure. They retain the flexible mechanical properties over a wide temperature range from 130 8C to 320 8C, as evidenced from thermal and mechanical analyses. Moreover, owing to their elasticity and bendability even at temperature of under 196 8C, we can successfully absorb and squeeze-out liquid nitrogen. In the case of (3-mercaptopropyl)trimethoxysilane-(3-mercaptopropyl)methyldimethoxysilane copolymer system, gold ions can be adsorbed on the pore surface by the mercapto groups. We employed a vinyltrimethoxysilane (VTMS)-vinylmethyldimethoxysilane (VMDMS) co-precursor system to prepare the first superamphiphobic monolith. The VTMSVMDMS marshmallow-like gel can be obtained by four simple, routine steps within half a day: 1) mixing VTMS, VMDMS, urea, and surfactant n-hexadecyltrimethylammonium chloride (CTAC) in a dilute aqueous acetic acid solution, and stirring for 60 min at room temperature for acid-catalyzed hydrolysis of alkoxysilanes; 2) transferring the resulting transparent sol to an oven for gelation and aging at 80 8C over several hours to promote the siloxane network formation under basic conditions, which is brought up by the hydrolysis of urea into ammonia; 3) washing with alcohol by hand; and 4) evaporative drying under ambient conditions (Figure 1a). The obtained gel (MG1) shows enough marshmallow-like flexibility to recover their original shape from 80% uniaxial compression and 3-point bending (Figure 2; Supporting Information, Figure S1). This material has a superhydrophobic surface with a water contact angle of 1538, which is due to the negligible amount of residual hydrophilic silanol groups, as characterized by Si solid-state cross polarization/ magic angle spinning (CP/MAS) NMR spectroscopy (Supporting Information, Figure S2). However, MG1 does not show oleophobicity, but absorbs organic liquids quickly like a sponge (Figure 3a) as mentioned before. [*] G. Hayase, Dr. K. Kanamori, Prof. K. Nakanishi Department of Chemistry, Graduate School of Science, Kyoto University Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan) E-mail: kanamori@kuchem.kyoto-u.ac.jp

Selective Preparation of Macroporous Monoliths of Conductive Titanium Oxides TinO2n–1 (n = 2, 3, 4, 6)

Monolithic conductive titanium oxides Ti(n)O(2n-1) (n = 2, 3, 4, 6) with well-defined macropores have been successfully prepared as a single phase, via reduction of a macroporous TiO(2) precursor monolith using zirconium getter. Despite substantial removal of oxide ions, all the reduced monoliths retain the macropore properties of the precursor, i.e., uniform pore size distribution and pore volume. Furthermore, compared to commercial porous Ebonex (shaped conductive Ti(n)O(2n-1)), the bulk densities (1.8 g cm(-3)) are half, and the porosities (60%) are about 3 times higher. The obtained Ti(n)O(2n-1) (n = 2, 3, 4, 6) macroporous monoliths could find applications as electrodes for many electrochemical reactions.

Spin‐Ladder Iron Oxide: Sr3Fe2O5

14 SPIN-LADDER IRON OXIDE: Sr3Fe2O5 H. Kageyama, T. Watanabe, Y. Tsujimoto, A. Kitada, Y. Sumida, K. Kanamori, K. Yoshimura, N. Hayashi, S. Muranaka, M. Takano , M. Ceretti, W. Paulus, C. Ritter, G. Andre Department of Chemistry, Graduate School of Science, Kyoto University, Japan Graduate School of Human and Environmental Studies, Kyoto University, Japan 3 Institute for Chemical Research, Kyoto University, Uji, Japan 4 Institute for Integrated Cell-Materials Sciences and Research Institute for Production Development, Japan 5 University of Rennes1, Sciences Chimiques de Rennes UMR CNRS 6226, Campus de Beaulieu, Rennes 6 Institute Laue Langevin, BP 156, 38042, Grenoble, France 7 Laboratoire Leon Brillouin, CEA-CNRS Saclay, 91191, Gif-sur-Yvette, France

Polymethylsilsesquioxane-cellulose nanofiber biocomposite aerogels with high thermal insulation, bendability, and superhydrophobicity.

Polymethylsilsesquioxane-cellulose nanofiber (PMSQ-CNF) composite aerogels have been prepared through sol-gel in a solvent containing a small amount of CNFs as suspension. Since these composite aerogels do not show excessive aggregation of PMSQ and CNF, the original PMSQ networks are not disturbed. Composite aerogels with low density (0.020 g cm(-3) at lowest), low thermal conductivity (15 mW m(-1) K(-1)), visible light translucency, bending flexibility, and superhydrophobicity thus have been successfully obtained. In particular, the lowest density and bending flexibility have been achieved with the aid of the physical supporting effect of CNFs, and the lowest thermal conductivity is comparable with the original PMSQ aerogels and standard silica aerogels. The PMSQ-CNF composite aerogels would be a candidate to practical high-performance thermal insulating materials.

Structural characterization of hierarchically porous alumina aerogel and xerogel monoliths

Detailed nanostructures have been investigated for hierarchically porous alumina aerogels and xerogels prepared from ionic precursors via sol-gel reaction. Starting from AlCl3.-6H2O and poly(ethylene oxide) (PEO) dissolved in a H2O/EtOH mixed solvent, monolithic wet gels were synthesized using propylene oxide (PO) as a gelation initiator. Hierarchically porous alumina xerogels and aerogels were obtained after evaporative drying and supercritical drying, respectively. Macroporous structures are formed as a result of phase separation, while interstices between the secondary particles in the micrometer-sized gel skeletons work as mesoporous structures. Alumina xerogels exhibit considerable shrinkage during the evaporative drying process, resulting in relatively small mesopores (from 5.4 to 6.2 nm) regardless of the starting composition. For shrinkage-free alumina aerogels, on the other hand, the median mesopore size changes from 13.9 to 33.1 nm depending on the starting composition; the increases in PEO content and H2O/EtOH volume ratio both contribute to producing smaller mesopores. Small-angle X-ray scattering (SAXS) analysis reveals that variation of median mesopore size can be ascribed to the change in agglomeration state of primary particles. As PEO content and H2O/EtOH ratio increase, secondary particles become small, which results in relatively small mesopores. The results indicate that the agglomeration state of alumina primary particles is influenced by the presence of weakly interacting phase separation inducers such as PEO.

New flexible aerogels and xerogels derived from methyltrimethoxysilane/dimethyldimethoxysilane co-precursors

We report new flexible “marshmallow-like” aerogels and xerogels with a bendable feature from the methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane (DMDMS) co-precursor systems. A 2-step acid/base sol–gel process and surfactant are employed to control the phase separation of the hydrophobic networks, which give porous monolithic gels. The obtained gels become softer and more flexible with increasing DMDMS fractions.

The thermal conductivity of polymethylsilsesquioxane aerogels and xerogels with varied pore sizes for practical application as thermal superinsulators

High-performance thermal insulating materials are desired especially from the viewpoint of saving energy for a sustainable society. Aerogel is the long-awaited material for extended applications due to its excellent thermal insulating ability. These materials are, however, seriously fragile against even small mechanical stress due to their low density, and their poor mechanical properties inhibit their practical use as superinsulators. In this paper, we report relationships between the thermal conductivity, pore size and mechanical properties of organic–inorganic hybrid polymethylsilsesquioxane (PMSQ) aerogels with improved mechanical properties and controllable pore sizes from ∼50 nm to 3 μm. The dependency of thermal conductivity on gas pressure and pore properties can be well explained by the thermal conduction theory of porous materials. These PMSQ aerogels show improved mechanical properties due to their elastic networks, which enable easier handling compared to conventional aerogels and facile production by simple ambient pressure drying. An aerogel-like “xerogel” monolithic panel has been successfully prepared via ambient pressure drying, which shows a low thermal conductivity (0.015 W m−1 K−1) comparable with those of the corresponding PMSQ aerogel and conventional silica aerogels. These results would open the gate for practical applications of these porous materials.

Rigid Crosslinked Polyacrylamide Monoliths with Well‐Defined Macropores Synthesized by Living Polymerization

Rigid crosslinked polyacrylamide monoliths with well-defined macropores have been successfully fabricated by organotellurium-mediated living radical polymerization (TERP) accompanied by spinodal decomposition. The TERP forms homogeneous networks derived from N,N-methylenebis(acrylamide) (BIS), in which spinodal decomposition is induced to form macropores. Macropore diameter can be controlled from submicrons to a few microns, and also the obtained networks contain mesopores in the macroporous skeletons, which are collapsed by evaporative drying. They are promising materials with hydrophilic polyacrylamide surfaces and have enough strength to preserve the macropores from the surface tension arising in the repetitive swelling and drying that may occur in many applications.