Research

About Our Laboratory

The Polymer Molecular Engineering (PME) Laboratory is one of the laboratories in the Department of Macromolecular Science and Engineering at Kyoto Institute of Technology, which consists of one staff member (Prof. Tomohisa Norisuye) and more than 10 undergraduate, master, and doctoral students who study the physical properties of polymeric materials. This laboratory was established in 2005 by Prof. Qui Tran-Cong-Miyata. Originally, when Prof. Miyata became a professor in 2001, Prof. Norisuye (assistant professor at the time.) was assigned to the lab, and the lab was maintained by two staff members. Prof. Miyata was working on photo-induced phase separation (using confocal microscopy, etc.), and Prof. Norisuye was working on polymer gels and organic-inorganic hybrids (using light scattering methods). Prof. Miyata retired in March 2018. After 17 years as an assistant professor and associate professor in the Miyata Lab, Prof. Norisuye became a full professor in 2018 and took over the lab. During this period, Professor Hideyuki Nakanishi, currently in the Nanomaterials Chemistry Laboratory, joined our laboratory activities as a staff member. Professor Nakanishi, a graduate of our laboratory, was appointed as an assistant professor in our laboratory in 2012, and continued his activities related to metal nanoparticles in our laboratory for about 10 years, working as an associate professor before being promoted to a full professor as of March 1, 2021. The current research in the PME Laboratory is characterized by the fact that, in addition to conducting research on the physical properties of microparticles, we are the first in the world to “develop a method for dynamic ultrasound analysis of nano/microparticles”. We have many original technologies as published in papers and patents. The ultrasound research began in 2004 when Prof. Norisuye studied abroad in the laboratory of Prof. John Page in Canada (Professor Emeritus, University of Manitoba). In addition to the research he learned in Canada, Prof. Norisuye is engaged in academic research and industry-academia collaboration using a number of new technologies developed at Kyoto Institute of Technology.

Recent Publications

What we have achieved so far: Dynamic analysis of nanoparticles

Dynamic light scattering (DLS) is a well-known method for measuring microparticles moving in liquids. Compared to light, dynamic light scattering (DLS) is often considered unsuitable for nanoparticle analysis because of its long wavelength. Ultrasound echo diagnosis is used to monitor the condition of the fetus. It’s a centimeter or millimeter technology. However, we have successfully overturned such conventional wisdom that nanoparticle analysis is not feasible because ultrasound has a long wavelength, and detected the motion of nanoparticles with ultrasound. Because of this, we were able to study the concentrated microparticles.

What we have achieved so far: correlation function method and phase imaging method

The so-called time correlation function method, which correlates the scattering signals, yields a time-averaged mean value by taking auto correlations. We have devised a new method that focuses on the phase of ultrasonic waves, and have constructed a completely new methodology for determining the motion of particles and the size of particles at an instant. Such a method utilizing the phase is not available in conventional light scattering, X-ray scattering, or neutron scattering methods. Not only is this a world first, but it leads to subsequent applications in sedimentation field imaging, direct analysis methods for particle size distribution (without inverse Laplace transform), and zeta potential measurement. Using the phase method, data compatible with the correlation function method can be obtained, and furthermore, motion information (velocity data) can be obtained in real time with a sign (information on the direction of particle motion). This allows for imaging of the sedimentation field with “one sensor” (usually an “array” of many sensors). We have also created a technique for analyzing particle size distribution separately for each particle size by taking advantage of the attractiveness of ultrasonic phase detection. Conventional light scattering and X-ray scattering methods obtain particle size distributions by assuming the existence and distribution of particles of various sizes. With our sedimentation dynamics analysis, individual particles are analyzed directly, so the particle size distribution can be calculated directly without assumptions. In addition, this phase technique allows monitoring of instantaneous velocities and thus real-time analysis of position-dependent electrophoretic velocities in the sample (for zeta potential measurements).

What we have achieved so far: viscoelastic ultrasonic scattering analysis

In the discipline of ultrasonic scattering, the so-called ECAH theory by Epstein-Carhart-Allegra and Hawley is very well known. Although it is a single scattering theory, it is one of the most accurate theories for ultrasonic scattering of spherical particles. However, in the long history of ultrasonic scattering studies (ultrasonic spectroscopy), only the viscosity of droplets has been considered for emulsions and the elasticity of solid particles for suspensions in the framework of the ECAH analysis. Therefore, due to the complexity of complex number analysis, it has not been possible to simultaneously consider the elasticity and viscous loss of particles. We have developed a new viscoelastic ECAH analysis method, which enables the analysis of rubber and elastomer particles as well as impact-resistant particles. In particular, in monitoring the drying of droplets and suspension polymerization, the droplets are initially liquid, passing through the viscoelastic region along the way, and finally becoming solid. In our laboratory, we analyze any material, whether gaseous, liquid, or solid, organic polymer, inorganic, or metallic particles.

ページトップ Page Top