Publications in 2009

"Phase Separation and Morphology of Polymer Mixtures", in "Polymers, Liquids and Colloids in Electric Fields - Interfacial Instabilities, Orientation and Phase Transitions", Q. Tran-Cong-Miyata and H. Nakanishi (Y. Tsori and U. Steiner Eds.), World Scientific, Chapter 6, pp. 171-196, 2009

"Effects of Light-Induced Regularity on the Physical Properties of Multiphase Polymers", Kosuke Murata, Tasuku Murata, Hideyuki Nakanishi, Tomohisa Norisuye, Qui Tran-Cong-Miyata, Macromolecular Materials and Engineering, 294, 3, pp. 163-168, 2009

"Physical Aging of Photo-Crosslinked Poly(ethyl acrylate) Observed in the Nanometer Scales by Mach-Zehnder Interferometry”, Dan-Thuy Van-Pham, Kazuhiro Sorioka, Tomohisa Norisuye and Qui Tran-Cong-Miyata, Polymer Journal 41, 4, 260-265, 2009, 2009

"Simultaneous Observation and Analysis of Sedimentation and Floating Motions of Microspheres Investigated by Phase Mode-Dynamic Ultrasound Scattering", A. Nagao, M. Kohyama, T. Norisuye, and Q. Tran-Cong-Miyata, Journal of Applied Physics, 105, 023526, 2009

"Dynamics of Microsphere Suspensions Probed by High Frequency Dynamic Ultrasound Scattering", M. Kohyama, T. Norisuye, and Q. Tran-Cong-Miyata, Macromolecules, 42, 3, pp. 752 - 759 (2009)

"The Roles Of Reaction Inhomogeneity In Phase Separation Kinetics And Morphology Of Reactive Polymer Blends", Q. Tran-Cong-Miyata, D.-T Van-Pham, K. Noma, T. Norisuye, H. Nakanishi, Chinese Journal of Polymer Science 27, 1, pp. 23−36, 2009

Research

In our laboratory, we have designed and controlled microscopic structure of polymeric materials by means of chemical or physicochemical approach. Among wide variety of studies on polymeric materials, manipulation of structure on the order of micron, which is compatible with the wavelength of the visible light, was challenging subject for producing new class of materials, such as photonics materials, optical devices and so on. To achieve this requirement, we have studied structure and its formation process for photochemically or chemically controlled polymeric materials by using spectroscopies and scattering techniques, such as light or X-ray scattering, confocal laser scanning microscopy, atomic force microscopy and so on. Our current interests cover polymer alloys, glasses and networks, which belong to a large group of polymeric multiple phase system.

Exploring physics by chemical approach

It is well known that polymer-polymer demixing occurs when two types of polymers are exposed under unfavorable condition by changing temperature or pressure. For polymer blends and block copolymers, there is a wide variety of patterns depending on the composition, interaction and conditions. Although controlling of morphology is one of the most important task to control thermal and/or mechanical properties of these materials, unfortunately, the resultant structure is not as uniform as one expects due to evolution of the shorter- or longer- unintersting wave contributions of the concentration fluctuations. Thus, we have applied introduction of chemical and/or cross-linking reaction using visible light to manipulate the structural evolution for these systems.

Learning a concept from nature

When ink sinks to water, it diffuses immediately, resulting in homogenous solutions. Howver, there are many exceptional patterns as found on animals, e.g., cow, leopard, zebra and etc. It is well known that it emerges as a consequence of "short range activator vs long range inhibitor" principle, which is often observed in living systems. With an aid of this concept, we have tried to construct a new class of structural materials, which has never been created by conventional techniques.

Order structure in MICRON

In the presenet, micro phase separation of block copolymers is one of the most convenient route to construct nano-ordered structure. On the contrary, tailoring the order structure on the scale of micron is quite difficult subject for polymeric systems. In order to achieve this, we have applied forementioned technique, "short range activator vs long range inhibitor" principle onto polymeric systems. In our studies, we combine chemical reactions, such as the photodimerization or photoisomerization, onto the phase separation of polymer blends. By applying the competitive reaction between the chemical reaction and phase evolution, which respectively corespond to the long- and short- range interaction, a wide variety of periodic structure can be obtained. Here is an example of reaction induced phase separated structure (Left: Conventional thermally-induced phase separation, Right: Reaction-induced phase separation) In order to control the structure more precisely, we have further introduced temporal modulation and spatial modulation onto the competitive principle, which must lead to unique materials with single period structure like low-molecular-weight crystals.

Spatio-temporal behavior under opened sytems

So far, most of the structural control has been carried out under the framework of thermodynamically equilibrium state (constant pressure, temperature and volume). On the contrary, this condition is not fulfilled under general manufacturing process, resulting in the large gap between them. In order to overcome this problem, systematic analyses for the polymer structure under the opened system is strongly demanded. We have carried out phase separation studies with temperature gradient and/or light intensity gradient. It must lead to elucidation of gradient structures for polymeric materials.

Structural analysis for networks

As mentioned above, our techniques combining the phase separation and chemical reaction have potential applications for polymeric materials. On the other hand, the analysis becomes difficult due to presence of cross-links or complicated reactions. Therefore we need more deep consideration about quantitative analysis for these new class of materials.

Confocal laser scanning microscopy or atomic force microscopy is one of the most powerful tools to observe the structure in three dimension. However, due to lack of sampling point on finite pixels, it is not always sufficient to achieve the complete analysis. Therefore, we have performed structural analysis by scattering techniques such as light, neutron and X-ray scattering. By comparing the Fourier transformation of image data observed in real space, we can compare the results mutually, leading to successful evaluation of the fine structure in three dimensional space.

Recent research themes

- REACTIVE POLYMER BLENDS -
(1) Controlling of phase separation of polymer blends by external periodic force
(2) Phase separation behavior for polymer blends induced by antagonistic interactions
(3) Controlling of phase separation by reversible chemical reactions
(4) Mach-Zehnder interferometric studies on microscopic deformation of reactive polymer blends
(5)Characteristic critical behavior of polymer blends induced by microscopic stimulation

- NANO COMPOSITES and GELS -
(6) Studies on two types of frozen inhomogeneities for polymer gels
(7) Dynamics inhomogeneities of polymer gels
(8) DLS and AFM studies on cluster evolution during gelation process
(9) Studies on microscopic structure for organically modified nano-hybrids
(10) Generation and fixation of multiple percolation structure in proton conductive membranes

Apparatus and Equipment

- Phase Contrast Microscope Equiped with IEEE1394 image data transfer system (Nikon)
- Reflecting Microscope
- Confocal Laser Scanning Microscopy (PASCAL, Carl Zeiss)
- Mach-Zehnder Interferometer (Homemade)
- Two Dimensional Light Scattering System (DYNA, Otsuka Co. Ltd)
- Static Light Scattering (Homemade, photographic method)
- Static Light Scattering (Homemade, for cloud point measurements)
- UV-VIS Spectrophotometer (Shimazu Co. Ltd)
- UV-VIS Spectrophotometer
- Fluorescence Spectrophotometer (Shimazu Co. Ltd)
- Inductance, Capacitance, or Impedance meter (HIOKI)

- UV irradiation system
- Vaccum line (Homemade)
- Environmental chambers (LHL-113, Espec)
- Electric Heating Furnace

In addition, we also employed the following apparatus:
Atomic Force Microscopy(AFM), Dynamic Light Scattering(DLS), Small-Angle X-ray Scattering(SAXS), Thermogravimetric analysis(TGA), Fourier Transform Infrared Spectroscopy(FTIR) and Gel Permeation Chromatography(GPC) equipped at our department.

Computer and Internet

- Desktop and Laptop Macintosh as well as Windows available
- Common file server accessible from both Mac and Win
- Internet connection at 100Mbps
- Local network connection at 1Gbps

- Sharing IP address by router
- Easy data transfer from the common PC to private PC
- High speed color and grey scale laser printers
- Sharing them via LAN is enabled
- Protecting from unauthorized access

- Equipped wireless access point at all the rooms
- Automatic detection of the most sensitive port
- Authorized for the member of PME

Polymer Molecular Engineering Laboratory
Department of Macromolecular Science and Engineering, Graduate School of Science & Technology,
Kyoto Institute of Technology,
Matsugasaki, Sakyo-ku, Kyoto 606-8585, JAPAN