An electrodeposition was developed to prepare a hybrid film with a nano structure. An anionic nanosheet colloid solution can be prepared by the addition of quaternary ammonium with the nanosheets being electrodeposited on the anode. The redoxable electrodeposited films were grown from solutions of the manganese oxide nanosheet. On substituting from the manganese to nickel or copper with several atom% within the manganese oxide nanosheet, electric conductivity increased and the resultant electrochemical capacitance improved. Other redoxable films in which ordered phosphate nanosheets interleaved polyaniline with monolayers were grown from solutions. These included a metal phosphate nanosheet and aniline monomer. The electrochemical capacitance of this hybrid films was approx. 180–200 F/g. Using an organo-grafted zirconium phosphate nanosheet, the graft worked as pillars to form nanovoids near to the polyaniline within the hybrid film. The resultant capacitance increased by approx. 1.8 times due to the development of an ion diffusion path.

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The present paper describes novel microfabrication techniques which utilize an ion migration at the microcontact between ion conductor and target solid. Two different methods have been recently proposed by our group. One is a solid state electrochemical route for pinpoint doping using an ion conductor. In this approach, an electric field is applied to the solid–solid interface between the cation conductor and target solid, inducing the injection of cations into the target. A significant advantage of this technique is that it enables pinpoint doping into desired locations within a solid target using the ion conductor having an extremely small contact area. On the other hand, we have also investigated an electrochemical microstructuring (i.e., micromachining) of metal surface through an anodic reaction of metal substrate attached to the needle-like ion conductor. The metal substrate is electrochemically oxidized, and then dissolves as Mⁿ⁺ into the ion conductor placed at the cathodic side. As a result of the continuous application of electric field, the metal surface is drilled according to the apex form of the ion conductor employed. This paper reveals the characteristics (merits and demerits) of the present techniques vis-a-vis conventional techniques for doping or micromachining.

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Comb-shaped ZnO powder was synthesized through the direct melt oxidation of a source material mixed with Al, Zn, and graphite in air at atmospheric pressure. The comb-like structures were fabricated when the source material mixed with graphite, whereas only tetrapod-shaped ZnO powder was obtained for the source material without graphite. This result shows that graphite played a crucial role in the formation of comb-shaped ZnO powder. Room temperature photoluminescence spectrum of the comb-shaped ZnO powder revealed a green emission with a maximum peak at 520 nm.

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Hollow magnetite (Fe₃O₄) spheres have been synthesized successfully via a template-free hydrothermal reaction using Fe-naphthenate and LiOH as the starting materials. The average diameter of hollow magnetite spheres prepared at 120°C was about 10 µm, and the specific surface area of the product was 68.3 m²/g. The size and morphology of the products depended on the reaction temperature, concentration of LiOH solution and the volume ratio of the oil (Fe-naphthenate) and water phase (LiOH solution). The hollow magnetite spheres exhibit ferromagnetic behavior with saturation magnetization (Ms), remanent magnetization (Mr), and coercivity (Hc) values of ca. 22 emu/g, 5 emu/g, and 530 Oe, respectively, according to the magnetic hysteresis curve measured at 5 K. The possible formation mechanism of hollow magnetite spheres is also discussed.

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The glass forming region of TiO₂–ZnO–P₂O₅ glasses was investigated at 1400°C, which is lower than the melting temperature of general titanophosphete glasses. TiO₂ could be added up to 15 mol% in the TiO₂–ZnO–P₂O₅ glasses. The glass forming region of 15TiO₂–ZnO–P₂O₅ was quite smaller than that of ZnO–P₂O₅, and the glasses with TiO₂ were colorized by the formation of Ti³⁺. The refractive index of the glasses increased with increases in the TiO₂ concentrations, and the maximum was 1.656. The glass transition temperature, T_g, of the glasses increased with increased TiO₂ concentrations, although T_g decreased with increases in the ratio of ZnO to P₂O₅. Raman spectra of the glasses suggested that P–O–Ti bonds were formed by the addition of TiO₂. The increase in T_g and the narrow glass forming region were caused by the formation of strong chemical bonds, P–O–Ti.

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This study presents dielectric and piezoelectric properties of piezoelectric thick film processed by electrophoresis deposition method. 1 µm–200 µm-thick film were fabricated by electrophoresis depostion method. The dielectric constant and piezoelectric property of the piezoelectric film increased as the film become thicker. When electric field <3 kV/mm was applied, their dielectric and piezoelectric properties were changed with respect to their thickness. At electric field = 5 kV/mm their properties are constant regardless of their thickness. These changes can be explained by existence of many void defects to be inevitabley introduced in thick film fabrication process, which can be one of crucial causes of controlling ferrroelectric properties of thick films.

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Free-standing TiO₂ nanotubes with both their ends open are required in many applications. This article reports the authors’ latest progress in meeting these requirements. Elevating the voltage at the end of an anodization process can break the adhesion of the TiO₂ nanotube layer to the underlying Ti substrate and simultaneously open their bottoms. Furthermore, by modulating the value and duration of the elevated voltage, the bottom morphology of the nanotubes can also be effectively tailored. Compared with most of the related work, in which obtaining free-standing TiO₂ nanotube layers and opening their bottom ends are often performed in two separate procedures, this newly-developed route features a simple one-step solution and also good controllability. Both the detachment of the nanotubes from the Ti substrate and the tailoring of their bottom ends are ascribable to the local acidification and gas evolution induced by the sudden voltage transition.

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Phase separation in an acidic aqueous solution with sodium silicate and sodium dodecyl sulfate (SDS) was investigated. The solution separated into silica-rich and SDS-rich phases during condensation of silica components. During the phase separation, the transition structure was fixed by gelation, resulting in mutually continuous morphology. The addition of a small amount of water-miscible organic solvents, such as methanol, ethanol, 1-propanol, and 1-butanol, into the reacting solution greatly decreases both viscosity and phase separation tendency of the solution. In the system with high concentration of strong acid, SDS molecules form wormlike micelles, which not only increase viscosity of the solution but also play an important role in the phase separation in the solution because the formation of wormlike micelles increases apparent molecular weight of SDS and decreases mixing entropy. The decrease in the viscosity by the addition of organic solvents suggests that wormlike micelles become small in the presence of organic solvent molecules. Consequently, the addition of appropriate amount of organic solvent is effective for controlling phase separation tendency and size of the resulted macropores in the system with SDS through the change in the structure of the micelles.

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Semiconductive dielectric SrTiO₃ thin films are promising candidates for the in situ monitoring of trace levels of oxygen in semiconductor manufacturing processes. Highly sensitive oxygen sensors were prepared by atomic-layer deposition (ALD) or pulsed-laser deposition (PLD) of SrTiO₃; however, there was a problem with ALD-SrTiO₃ that surface defects, such as SrO surface segregation with a minor contribution from SrO₂, affected the detection below an oxygen concentration [P_O2/(P_O2 + P_He)] of 1.1 × 10⁻¹², causing the reversion of ALD-SrTiO₃ to a slightly high-resistance state. The coverage of the segregated surface of SrO and SrO₂ on the ALD-SrTiO₃ was considerably higher than that observed on the PLD-SrTiO₃ surface, however, the reversion could be markedly suppressed by the additional thermal treatment, probably owing to gathering small SrO-based surface islands (building-up of bigger islands), resulting in the exposure of clean surfaces.

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Superionic Li⁺ ion conducting Li₇P₃S₁₁ crystal was prepared by crystallization of the 70Li₂S·30P₂S₅ (mol %) glass and melt. In the case of crystallization of the 70Li₂S·30P₂S₅ glass, the crystallized electrolyte heated at 360°C for 1 h showed a conductivity of 4.1 × 10⁻³ S cm⁻¹ at room temperature. In the case of crystallization from the 70Li₂S·30P₂S₅ melt, a single phase of the Li₇P₃S₁₁ crystal was obtained by crystallization of the melt at 700°C for 48 h and then quenching in ice water. The crystallized electrolyte showed the conductivity of 2.9 × 10⁻³ S cm⁻¹ at room temperature. The precipitated crystal depended on the heat treatment temperature, holding time, and cooling rate. In both crystallization processes from the glass and melt, the Li₇P₃S₁₁ crystal was precipitated as a primary phase from supercooled liquids and thus the superionic conducting Li₇P₃S₁₁ crystal is a high temperature phase at the composition 70Li₂S·30P₂S₅.

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The electrophoretic movement of colloidal silica particles with hollow interior and nanoporous shell structure was examined under a homogeneous direct current (DC) electric field as a function of field strengths (50–150 V) and solution pHs (4–10). The electrophoretic behavior was compared with that of solid silica particles of similar size. In an acidic solution (pH ∼4) at which the solution pH near the PZC (pH ∼2), mobility of the hollow particles appeared to be insensitive to the change of applied voltage in a dilute solids concentration. As pH moved away from the PZC to a basic solution (pH ∼10), velocity of the charged particles increased pronouncedly and the velocity was in a linear proportion with the DC field strength, suggesting that the particles were moved by electrophoresis. The hollow silica particles yet showed a much slower electrophoretic velocity, less than one half, than that of the solid counterparts at the alkaline situation (pH ∼10). This lagged motion was due presumably to the rough outer surface and the permeable shell structure (pore radius ∼20 nm), both contributing to the hydrodynamic friction that retards the electrophoretic movement.

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Forces between α-alumina surfaces in NH₄⁺ salt of poly(acrylic acid) (NH₄-PAA) and methyl cellulose polymer solutions at pH 9 were measured by colloid probe technique. The effect of water soluble methyl cellulose, with and without the presence of surfactant (NH₄-PAA), on the surface forces was probed to understand the binding action of methyl cellulose between particles. Two types of cantilevers were used to probe the surface forces in the presence of adsorbed polymers at various concentrations. Strong polymer concentration dependence of surface forces was found. At high polymer concentrations due to the high coverage of surfaces, repulsive forces dominated the interaction. Methyl cellulose bridges have been measured up to ∼300 nm. The pre-treatment of surfaces with NH₄-PAA resulted in much lower number of bridging events on retraction.

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Crystallization of silica glasses of various types by contact with a NaCl crystal grain was investigated. The depth of the center of the crystallized region was proportional to the square root of the heating time. The temperature-dependence of the depth at the fixed time is linear in the Arrhenius plot at temperatures higher than approximately 1000°C, and for slopes bent at approximately 1000°C.

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A soft lithography technique was used to create patterned green ceramic films including micrometric voids of well-defined geometry. A PDMS mold was filled by high solid content aqueous suspension (40–52% vol.) and the process quality as well as the film green density were evaluated through SEM and non-contact profilometry. Drying is a critical step, as limited shrinkage was observed due to wetting of the elastomer by water. The drying conditions were optimized in order to increase the homogeneity and green packing of the structured films. Controlled geometry features of high aspect ratio were produced down to the micrometer scale. There are many technological uses of patterned films. In this study, we have used this approach to introduce controlled flaws and investigate constrained sintering and crack growth.

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Needle-like α-Fe₂O₃ particles with the length of 2 µm and the width of 250 nm were prepared by thermal decomposition of β-FeOOH and the electrochemical performances in the all-solid-state cells were examined. The cell using needle-like particles with acetylene black as a conductive additive showed the first discharge capacity of about 700 mAh g⁻¹ at the current density of 0.064 mA cm⁻². The lithium ion and electron conduction path of the electrode was improved by using vapor grown carbon fiber as a conductive additive. The needle-like α-Fe₂O₃ particles were compared with α-Fe₂O₃ spherical particles; the suitability for the active material of all-solid-state batteries was investigated.

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