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Nanotechnology / Materials: 26
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- Information and Communication
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Soft Viscosity Ferroelectric Crystal
Development of organic ferroelectrics with freely controllable polarization direction
We have developed a ferroelectric material using deformable flexible crystals. This material can easily be processed in solution and can be stretched under pressure. Unlike conventional organic ferroelectrics, the material can be polarized in three dimensions, so that even discs and thin films of microcrystalline powder exhibit large polarization like single crystals.
Research
Ferroelectrics are important electronic materials with a variety of applications, such as non-volatile memories, piezoelectric devices and sensors that take advantage of their diverse functions. Most of the ferroelectrics that have been commercialized so far are inorganic oxides, such as barium titanate, which are known as chitabari in Japan. However, they are difficult to process using the solution method, and many of the useful materials contain toxic lead. Organic ferroelectric crystals, which have been actively developed in recent years, cannot be used in polycrystalline materials because polarization processing that changes the polarization direction in three dimensions is impossible. The flexible ferroelectric crystals we have recently developed can change the polarization direction almost freely, so that the polarization direction of polycrystals in disks and thin films can be aligned to create a polarization state close to that of a single crystal. They can also be stretched and expanded under pressure at high temperatures. In other words, this flexible ferroelectric crystal is a ferroelectric material that combines the advantages of conventional materials such as inorganic oxides, organic crystals and polymers.
Jun Harada Associate Professor -
Sonoplasma Generator
A method to generate acoustic cavitation in a fixed location with high efficiency
Upon the collapse of acoustic cavitation driven by ultrasonic waves in water, the bubble becomes hot and pressure inside increases, turning to plasma (sonoplasma). We have found a way to generate acoustic cavitation in a fixed location with high efficiency, and are working to develop it as a plasma application technology.
Research
Plasmas generated in liquid are of great interest in the fields of nanotechnology, environmental engineering and medical engineering, but the need for high voltage to generate the plasma can be an obstacle. Meanwhile, in the field of ultrasonic engineering, it is known that the interior of a bubble becomes plasma at the same time as the collapse of acoustic cavitation. Using a very simple method of inserting a perforated metal plate into a liquid where ultrasonic waves are applied, we have succeeded in localizing and efficiently generating acoustic cavitation, which is difficult to fix in position. This has been valued as a unique method of generating plasma in liquid without using high voltage. Currently, we are working to clarify the mechanism of this method and to prepare guidelines for the design of a large-scale device. In the future, we hope to develop various new plasma application technologies.
Koichi Sasaki Professor -
Stabilization of Nanoparticles Using Cyclic Poly(ethylene Glycol)
A novel stabilization method relying on the “topology” of polymers
In this research, we developed a novel dispersion stabilization method for metal nanoparticles using cyclic poly(ethylene glycol). The research group has found that molecular aggregates consisting of cyclic polymers have excellent stability. By applying this phenomenon, the dispersion stability of nanoparticles can be enhanced.
Research
A large number of nanoparticle-based drugs are currently investigated, including drug delivery system (DDS) carriers, many of their surface is covered with biocompatible poly(ethylene glycol) (PEG). In this regard, we have found that gold nanoparticles (AuNPs) modified with cyclic PEG exhibit high dispersion stability at high salt concentrations. In other words, AuNPs treated with cyclic PEG with a molecular weight of 4000 retained their dispersion stability for one week or longer in a 180 mM NaCl solution, which is a higher concentration than physiological conditions, whereas AuNPs treated with linear PEG of the same molecular weight started aggregating and precipitating within 3 hours in a solution of only 45 mM NaCl. This novel method using cyclic PEG can be applied to a variety of nanoparticle-based drugs including contrast agents and magnetic nanoparticles.
Takuya Yamamoto Associate Professor -
Superomniphobic Aluminum
Simple production of antifouling surfaces through a wet process
We have successfully fabricated a micro/nano-hierarchical surface morphology through chemical etching/anodization of aluminum sheets and meshes. By coating the surface with a fluoroalkyl monolayer, we have also succeeded in obtaining a surface that is not wetted by almost any liquids, including oil.
Research
It is expected that superomniphobic surfaces, which do not get wet with water or oil, will possess antifouling and self-cleaning properties. In this study, we have realized a superomniphobic surface that does not only repel water but also octane and other liquids with a surface tension as low as 20 mN m-1, by using a simple wet process for aluminum, which is a practical metal material. This process can also be applied to aluminum foil, which can be used as an antifouling surface in various places. It can also be used as a filter to separate oil and water by controlling its wettability using aluminum mesh.
Hiroki Habazaki Professor -
Synthesis of Fluorinated Aromatic Carboxylic Acids
Using electricity to make useful carboxylic acids from carbon dioxide
We have succeeded in regioselectively synthesizing a variety of fluorine-containing aromatic carboxylic acids, which are promising as new fluorine-containing building blocks, from readily available aromatic compounds containing several fluorine atoms and carbon dioxide, and achieved good yields by organic electrolysis.
Research
The introduction of fluorine atoms into organic compounds is very important in the fields of medicine, agrochemicals, and functional materials. There is a method of synthesizing fluorine-containing organic compounds by using fluorine-containing building blocks, but such compounds are still expensive and limited in quantity, and there is a high need for research and development. In this study, we succeeded in synthesizing fluorine-containing aromatic carboxylic acids with various functional groups from readily available fluorine-containing aromatic compounds and carbon dioxide, and achieved good yields using the organic electrolysis method. The fluorine-containing aromatic carboxylic acids synthesized in this study include a variety of new compounds that are difficult to synthesize by conventional methods, and are expected to be used as promising new fluorine-containing building blocks for the synthesis of pharmaceuticals, agrochemicals, and highly functional materials.
Hisanori Senboku Associate Professor -
Ultra-rapid Deposition of Photocatalytic Crystalline Titanium Dioxide Thin Films
Ultra-rapid electrochemical deposition technology that does not require high temperature heat treatment
Crystalline titanium dioxide is a practically important oxide as a photocatalyst. We have developed a technology to form crystalline titanium dioxide thin films, which generally require heat treatment at high temperatures, on various metal substrates within only a few seconds using an electrochemical deposition method in aqueous solution.
Research
We have succeeded in obtaining titanium dioxide thin film on a practical metal substrate such as Cu, Al, Zn and Fe by electrolysis from an aqueous solution containing TiF62- within only a few seconds. The obtained titanium dioxide thin film is anatase crystalline and shows photocatalytic activity without heat treatment. The obtained titanium dioxide thin film is anatase crystalline and shows photocatalytic activity without heat treatment. We have confirmed that it has excellent properties such as decomposition of organic contaminants on the surface by UV irradiation and superhydrophilicity. Since the titanium dioxide film is doped with substrate elements, the development of new functions such as visible light responsiveness can be expected. It can also be deposited on a transparent conductive substrate.
Hiroki Habazaki Professor
