• One of our major research focuses is to design the novel drug nanoparticles, so called “Nano-prodrugs”, and to apply them as anticancer drugs or eye drops with excellent delivery efficiency. Nano-prodrugs are constructed by synthetic prodrugs molecules which contains poorly water-soluble substituent. They could be fabricated to nanoparticles with 100 nm or less in size by our reprecipitation technique, which has been used to create organic nanomaterials. We are aiming at practical application of our Nano-prodrugs in the near future.

Our reprecipitation technique for fabricating organic nanomaterials is a versatile technique that can be applied to various organic molecules as well as drug compounds. We hope to conduct collaborative research with a willing company on controlling and evaluating properties of the organic nanoparticles.

• One of our major research focuses is to design the novel drug nanoparticles, so called “Nano-prodrugs”, and to apply them as anticancer drugs or eye drops with excellent delivery efficiency. Nano-prodrugs are constructed by synthetic prodrugs molecules which contains poorly water-soluble substituent. They could be fabricated to nanoparticles with 100 nm or less in size by our reprecipitation technique, which has been used to create organic nanomaterials. We are aiming at practical application of our Nano-prodrugs in the near future.

Our reprecipitation technique for fabricating organic nanomaterials is a versatile technique that can be applied to various organic molecules as well as drug compounds. We hope to conduct collaborative research with a willing company on controlling and evaluating properties of the organic nanoparticles.

• Our research aims at developing methods, including instrumentation, for characterizing surface (or interface) at the nano-meter level. Most of our research subjects are related to the surface forces measurement, which can directly monitor the interaction between two surfaces. We study phenomena occurring at the solid-liquid interface such as adsorption and structuring of liquids. We have developed the resonance shear measurement which is a sensitive method for evaluating properties of confined liquid for nano-rheology and tribology. Twin-path surface forces apparatus we developed enabled us to study wide variety of samples such as metals, ceramics and plastics.

These methods are applicable for characterizing lubricants, nano-materials, paints, sealants, and cosmetics. We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.

• It is well known that nano-scale impurity/solute clusters, defects, defect clusters and their complexes affect the mechanical and electrical properties in materials. However, it is very difficult to observe these objects even by state-of-the-art electron microscopes. We overcome the difficulty by employing noble two techniques: laser three-dimensional atom probe (3D-AP) technique and positron annihilation spectroscopy (PAS). Laser 3D-AP can map out each atom in various materials (metals, semiconductors, insulators) in three-dimensional real space with nearly atomic scale resolution. PAS can detect vacancy-type defects and defect-impurity complexes very sensitively.

By combining these methods, we are going to reveal the functions of the fine impurity clusters and defects to the materials: developments of new nano-structured materials, the mechanism of degradation of aged structural materials, the fall in the yield of semiconductor device production, and developments of quantum devices etc.

• Our research aims at developing methods, including instrumentation, for characterizing surface (or interface) at the nano-meter level. Most of our research subjects are related to the surface forces measurement, which can directly monitor the interaction between two surfaces. We study phenomena occurring at the solid-liquid interface such as adsorption and structuring of liquids. We have developed the resonance shear measurement which is a sensitive method for evaluating properties of confined liquid for nano-rheology and tribology. Twin-path surface forces apparatus we developed enabled us to study wide variety of samples such as metals, ceramics and plastics.

These methods are applicable for characterizing lubricants, nano-materials, paints, sealants, and cosmetics. We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.

• The objectives of my researches are the development of high performance magnets and improvement of their magnetic properties. I have already developed following high performance magnets, such as Nd-Fe-B magnets using didymium, Sm-Fe-N high coercive powders prepared by HDDR and Fe-Cr-Co magnets. Recently, I have studied about the reduction of Dy content in Nd-Fe-B magnets for the use of HEV and have succeeded to develop high coercive Dy-free Nd-Fe-B sintered magnets by decreasing the grain size. I have also developed new kinds of microwave absorbers for the use in the frequencies of GHz range using permanent magnetic materials or nanoparticles.

High performance magnetic materials can be used in many applications in automobile, home electronics, IT and medical industries. We hope to conduct collaborative researches with companies producing magnetic materials for the use in these applications, which aims to improve magnetic properties or to develop new magnetic materials.

• For further social development, it is required the miniaturization, weight saving, high performance of various devices. We study on fiber, particle reinforced polymer, metal, ceramic matrices composite materials using our knowledge about materials mechanics and numerical simulation such as finite element method. We recently address to develop multi-functionalized composite materials, which have high strength, super lightweight, energy harvesting function, damage monitoring function, biodegradable at the same time.

• 1) We investigate interesting properties of nanostructures and develop materials and devices utilizing nanostructures.
• 2) We have techniques and skills on low-noise electric measurements, cryogenics, nanofabrication, and data informatics. We are open to new collaborations.

• In our laboratory, miniature and highly-functional photonic devices based on new optical phenomena caused by the interaction of ultrafine microstructures with light have been studied. In addition, development of new production technology to overcome the problems that have been obvious from the practical application viewpoint of nanophotonic devices has been performed.
• • -Main research topics--
  MEMS tunable metamaterials for optical control.
• Structural color filters using subwavelength gratings for the applications of display and spectroscopic analyzers.
• Surface-smoothing technology using surface self-diffusion.
• Study of low loss silicon nanophotonic devices.

We aim to realize optical filters, optical resonators, and color filters, by using above technologies. Also, development of nano-photonic elements fabricated by a nanoimprint technology has been progressed.
We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.

Light curing high strength resin mold
https://www.t-technoarch.co.jp/data/anken_en/T11-053.pdf

• Nakagawa group has dedicated to pursue scientific principles for molecular control of interface function occurring at polymer/other material interfaces and to put them into practice in nanoimprint lithography promising as a next generation nanofabrication tool. We are developing advanced photo-functional materials such as sticking molecular layers for "fix by light", UV-curable resins and antisticking molecular layers for "preparation by light", fluorescent resist materials for "inspection by light", and hybrid optical materials "available to light" and new research tools such as mechanical measurement systems to evaluate release property of UV-curable resins.

Our research aims at creating new devices to control photon, electron, and magnetism.

• Monoatomic layered materials of Graphene, Transition metal sulfide nanosheet, nanocrystalline active materials, nanoparticles and nanoporous materials are investigated for realizing high capacity, high power, high safety and low cost energy storage devices as a post- Lithium ion battery. Advanced chemistry of functional materials and device processes for All solid state battery, Magnesium battery, fuel cells, supercapacitor and wearable batteries are investigated.

Academia – Industry collaboration with manufacturing companies of functional materials, batteries, and also smart grid, renewable energy, electrical power companies are encouraged for developments of advanced energy materials and post-Lithium ion battery.

• The objectives of my researches are the development of high performance magnets and improvement of their magnetic properties. I have already developed following high performance magnets, such as Nd-Fe-B magnets using didymium, Sm-Fe-N high coercive powders prepared by HDDR and Fe-Cr-Co magnets. Recently, I have studied about the reduction of Dy content in Nd-Fe-B magnets for the use of HEV and have succeeded to develop high coercive Dy-free Nd-Fe-B sintered magnets by decreasing the grain size. I have also developed new kinds of microwave absorbers for the use in the frequencies of GHz range using permanent magnetic materials or nanoparticles.

High performance magnetic materials can be used in many applications in automobile, home electronics, IT and medical industries. We hope to conduct collaborative researches with companies producing magnetic materials for the use in these applications, which aims to improve magnetic properties or to develop new magnetic materials.

• Hybrid materials that show multi-functions of polymer and nanoparticles are expected to be used in future industries, and thus many research and development have been actively conducted. However, since the affinity of polymer and inorganic nanoparticles is very low, in most of the cases, properties of different materials are incompatible in the hybrid materials. To create the hybrid materials with incompatible multi-functions has been considered a difficult task.
• However, by using supercritical fluid technology, we have succeeded in making hybrid materials with incompatible multi-functions.

Now, variety of hybrid materials are being developed, including
・Transparent, flexible, high reflective index, and high fabricability,
・Flexible, high heat conductivity, low electric resistivity, and high fabricability.

• We invented supercritical hydrothermal synthesis method for the synthesis of organic modified nanoparticles (NPs). Under the supercritical state, the organic molecules and metal salt aqueous solutions are miscible and water molecule works as an acid/base catalyst for the reactions. Organic-inorganic conjugate NPs can be synthesized under this condition. This hybrid NPs show high affinity with the organic solvent or the polymer matrix, which leads to fabricate the organic inorganic hybrid nanomaterials with the trade-off function (super hybird nanomaterials). These hybrid materials of polymer and ceramics fabricated with NPs achieve both high thermal conductivity and easy thin film flexible fabrication, namely trade-off function.

For example, by the surface modification of BN particles by supercritical method, affinity of BN and polymers could be improved, so that high BN content of hybrid materials, thus high thermal conductivity materials, could be synthesized. Also by dispersing high refractive index NPs like TiO2 or ZrO2 into polymers transparently, we can tune the refractive index of the polymers. CeO2 nanoparticles are expected to be used for high performance catalysts. To transfer those supercritical fluid nano technologies, a consortium was launched with more than 70 companies.

• Organicl compounds, such as liquid-crsytals, polymers, etc., can be hybridized with inorganic materials in atomic level, in particuar, with nanoparticles. Both of high effeciency of processing ease for the former and high possibilities of physical properties for the latter can be attained through the complete solution of trade-off characteristics. For example, this atomic-level hybridization technique makes inorganic nanoparticles active for the response like a liquid crystal. By using this method, we expect we can conduct effective collaborative research in medical fields.

• Nanoparticles and/or fine particles to be used for functional materials, such as semiconductor, photocatalysts, dielectric and/or piezoelectric materials, cosmetics, catalysts, etc., has been synthesized in liquid-phase. Their size, shape, composition, and structure have been <strong>precisely controlled</strong> along an expected usage. <strong>Tailor-made synthesis method</strong> has been provided for nanoparticles and/or fine particles the companies wish to use.

Until now, we have been supplying nanoparticles and/or fine particles of ITO (Indium Tin Oxides) as TCO, Bi based or Nb based particles for lead-free piezoelectric ceramics, perovskite-based oxides for dielectric materials etc. The gel-sol method as the main synthesis method for uniform particles makes the production cost reduced.