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International audience; Polysaccharide nanorods (chitin, cellulose) can be used as colloidal templates to form silica-based mesoporous materials by combining self-assembly and sol-gel chemistry. Chitin nanorods are chosen here for their self-assembly properties, facile preparation from natural resources, and because of the complexing properties of the free amino groups at their surface in view of further functionalization. Electrospinning of ethanolic co-suspensions, containing the chitin nanorods as pore templates, siloxane oligomers as silica precursors and polyvinylpyrrolidone (PVP) as spinning polymer, allows for forming mats of hybrid organic-inorganic fibers with diameters in the 200-300 nm range. The relative proportions of each component can be adjusted to meet specific characteristics (e.g. micro-/mesoporosity ratio). After calcination, the fibers present an open porosity studied by TEM and N2 volumetry. Elongated mesopores (100-200 nm long, 2-4 nm wide) are created by individual chitin monocrystals forming the nanorods. They are highly oriented along the fibers' axes with orientational order parameters P2 > 0.95 for volume chitin contents chitin* ≥ 0.2. Additional microporosity is provided by the removal of the spinning polymer, PVP. Complementary viscosity measurements on the initial cosuspensions allow discussing the interactions between colloids and their possible impact on the materials' textures observed. The introduction of a monomeric Ti 4+ precursor in the co-suspensions leads to isolated and tetrahedral Ti units, distributed in the calcined porous silica fibers and possibly close to the pores surface. In addition, preliminary investigations on processing the fibers with a Zn xanthate as ZnS precursor leads to carbonized fibers with nanoparticles and a Zn/S molar ratio close to 1.

メチルセルロース水溶液は, ゼラチンなどで見られるゾルーゲル転移とは逆に, 温度の上昇によってゲル化する物理ゲルとして大変興味深い物質である。また, モノマー中に親水基と疎水基を持つため, 両親媒性分子の性質を有すると考えられ, 凝集過程においてもその特徴が反映されると予想される。そこで, ゾル, ゲル, 相分離の各相を保つ温度において, 親水性ガラス基板上で溶媒を蒸発させた時の各乾燥膜の形成過程と結晶形状の比較検討を, 透過型偏光顕微鏡, AFM, MDG広角X線散乱などを用いて行った。その結果, 自己組織化により高分子鎖を折りたたみながら乾燥膜を形成するが, 膜周辺と膜中心部とでは繊維軸の配向が異なることが示唆された。, Methyl cellulose aqueous solution is an interesting material, which shows the reverse sol-gel transition temperature dependence with the gelatin. We have derived phase diagrams for aqueous solution methyl cellulose. Then, based on this phase diagram, we examined how physical gel like the methyl cellulose aqueous solution shows the selfassembly in drying process at the temperature which keeps each condition, such as the sol, gel and phase separtaion state. Comparison examination of crystalline morphology of each drying film formed under the abovementioned condition was tried using polarizing microscope (OM), WAXS, AFM. For around the spreading droplet, there is a thin film made by solvent evaporation. The any thin films obtained regardless of drying conditions of sol and/or gel, showed the Maltese cross and the birefringent pattern like negative spherulites at the OM observation. Furthermore, it was indicated by WAXS using MDG that the crystalline morphology of the droplet, which was formed under the condition of gel, is fold chain crystal.