| POLYMERS Vol.71 No.2 |
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COVER STORY
Cross and Inter Disciplinary Research |
| COVER STORY: Highlight Reviews |
| Becoming a “Catalyst” for Art and Chemistry | Keishi OHASHI |
| <Abstract> With the aim of exploring new applications for electrochromic materials developed for ultra-low power consumption displays, multiple experts from different fields have attempted to take on the challenge of realizing pixels that are not bound by conventional values. This paper reports on the process of collaboration among the different fields of art and design, chemistry, and electronics in the challenge “Falling Leaves Project”. Keywords: Electrochromism / Chemistry / Art / Electronics / Interdisciplinary Field / Display / Pixel / Fallen Leaves |
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| COVER STORY: Topics and Products |
| Toughening and 3D Printing of Blood-Compatible Polymer | Fumio ASAI, Yukikazu TAKEOKA |
| <Abstract> Poly(2-methoxyethyl acrylate) (PMEA) has attracted attention as a biocompatible polymer that is used as an antithrombotic coating agent for medical devices. However, PMEA is a viscous liquid polymer with low Tg, and its physical strength is poor even if a cross-linker is used, so it is difficult to make tough and freestanding objects from it. Here, we design and fabricate a biocompatible elastomer made of tough, self-supporting PMEA-silica composites. The toughness of the composite elastomer increases as a function of silica particle filling, and the stress at break of it is significantly improved. In addition, the composite elastomer shows the potential to have an antithrombotic property, while the results of the platelet adhesion test of the composite elastomer show that the number of adhered platelets is not significantly affected by the silica addition. Since the composite elastomer can be rapidly 3D-printed into complex geometries, it is expected to contribute to the development of medical devices from readily available materials. Keywords: Composite Elastomer / Toughness / Nonlinear Elasticity / Blood Compatible / Stereography |
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| Novel Baking Technology Based on Polymer Processing Technique | Akihiro NISHIOKA |
| <Abstract> The process of bread baking in food science corresponds to the foam molding process of the polymer processing science. Strong correlation between the melt rheological properties and the processability is commonly recognized. When we obtain the proper viscoelastic property of rice batter, then rice bread is possible to make. Development of this bread making technology is based on the idea to use amorphous rice flour as thickening agent. In addition, we developed a novel production method of amorphous rice flour by using a mill. This method was realized by a newly invented mill system called Shear and Heat Milling Machine (SHMM). It was clarified that the rheological properties such as strain hardening of rice dough is controlled by adding the amorphous rice flour obtained from the SHMM. High quality rice bread is possible with rice batter even without gluten. Recently, investigations on the effect of starch molecular architecture influencing the processability of rice dough are conducted. In the future, these series of studies will finally reveal a correlation between the architecture of starch molecules and the bread-making property. Keywords: Polymer Processing / Rheology / Starch / Baking Technique / Amorphous Rice Flour |
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| Utilization of the Unused Resources Using Nanofibrillation Technology in Agriculture | Hironori KAMINAKA |
| <Abstract> For utilization of waste crab and prawn shells known as representative unused waste resources, the effective use of chitin, a major component of fungal cell walls and arthropod exoskeletons, is essential due to its various physiological functions in living organisms. The utilization of chitin in agriculture has been limited due to its insolubility although chitin can induce disease resistance and growth promotion in plants. Nanofibrillation technology can produce chitin nanofiber (CNF) with high dispersibility even in water. Nanofibrillation technology was also applied to crab and prawn shells and spent mushroom substrate (SMS), which produces a CNF complex with other components. CNF induced disease resistance and promote growth in plants like other derivatives. CNF complexes derived from both shells conferred stronger plant disease resistance than standard CNF. The function of CNF complex produced from SMS would be derived from cellulose but not chitin. Our findings proposed nanofibrillation is a promising technology to produce functional and valuable new materials from unused resources in agriculture. Keywords: Chitin Nanofiber / Crab Shells / Disease Resistance / Growth Promotion / Nanofibrillation / Plant / Prawn Shells / Spent Mushroom Substrate |
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| New Mechanical Strengthening Concept of Polymer Millefeuille Structure with Kink Control | Akira ISHIGAMI, Hiroshi ITO |
| <Abstract> A new type of high strength magnesium (Mg) alloy having a long-period stacking ordered (LPSO) structure has been discovered in the field of metals. The LPSO structure was formed by a combination of hard and soft layers generating a mille-feuille multilayer-like structure. A kink structure was formed by hot forging the mille-feuille materials, resulting in improvement of mechanical strength of the materials. However, the kink formation and strengthening mechanism have not clearly been understood yet. In this study, the fabrication of polymer multilayer films having mille-feuille-like structures has been investigated. The effect of injection molding and heat treatment conditions on formation of the SBS microphase-separated structure as mille-feuille has also been analyzed. We have investigated various kink forming methods to clarify the relationship between the kink structure and mechanical properties of these polymer mille-feuille structures. Keywords: Mille-Feuille Structure / Polymer Multilayered Film / Triblock Copolymer / Kink Formation / Mechanical Strengthening |
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| Gel Actuator | Yusuke HARA |
| <Abstract> Soft actuators made of soft materials such as polymer gels and conductive polymers are lightweight and flexible, can be driven silently and have excellent molding processability. Such properties are not found in conventional actuators (electromagnetic motors, hydraulic pumps, etc.) used in the fields of mechanical engineering and robotics. In the field of robotics, soft actuators are adopted as a power source for small robots. In addition, soft actuators are also being used for pumps and valves that are driven in microfluidic systems. The soft actuator can operate by various external stimulations such as light, electric field, pH, and chemical reaction. This topic is introducing the outline of the results obtained by collaborating with researchers in robotics, mechanical engineering, and analytical chemistry regarding the self-oscillating gel actuators driven by the Belousov-Zhabotinsky (BZ) reaction. Keywords: Soft-Actuator / Gel / BZ Reaction / Robotics / Mechanical Engineering / Microfluidic Systems |
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| Living Hydrogels Generated by Click Cross-Linking Reactions of Azide-Modified Cells with Alkyne-Modified Polymers and Its Biomedical Applications | Koji NAGAHAMA |
| <Abstract> To date, many scientists have investigated both cells and cellular functions, resulting in the identification of molecular mechanisms underlying the cellular functions. Based on these findings, medical scientists and pharmacologists have developed many technological applications for cells and cellular functions in medicine. How can polymer scientists utilize cells and cellular functions? Here, we show a new concept for utilizing cells and their functions from the viewpoint of polymer science. In particular, we for the first time develop cell cross-linked living bulk hydrogels by bioorthogonal click cross-linking reactions of azide-modified mammalian cells with alkyne-modified biocompatible polymers. Importantly, we demonstrate the novel and unique functionalities of the living hydrogels, originating from the basic functions of the cells incorporated in the living hydrogels as active cross-linking points. The findings of this study provide a promising new route to generating living cell-based next-generation innovative materials, technologies, and medicines. In this report, we describe the unique functions of the gels and its biomedical applications. Keywords: Hydrogels / Cells / Alginate / Click Reaction / Self-Healing Capability / Tissue Engineering / Mechanobiology |
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| Polymer Science and I: A Personal Account |
| Entropy Follows Me | Manabu INUTSUKA |
| <Abstract> This is a story when I was a university student. I loved entropy, but entropy did not love me. The more I learned, the less I knew. So we decided to go our separate ways. But later, entropy came to see me again... with polymer ! |
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| Front-Line Polymer Science |
| Polymer Modulator for Ultra-High Speed Optical Fiber Communications | Shiyoshi YOKOYAMA |
| <Abstract> Recent progress of highly efficient and high-speed electro-optic (EO) modulator technology has received intensive research attentions in microwave photonics and fiber-optic networks. Among the different types of materials used in the modulator, the EO polymer offers intrinsic advantages such as a large EO coefficient, low dielectric constant and loss, and excellent compatibility with other materials and silicon substrates. Therefore, the EO polymer modulators open up a variety of opportunities for realizing unique wideband applications. In particular, achieving higher baud rates is an important objective toward optical interconnection at short-reach applications, so that the polymer modulator might be a cost-effective >100 G serial solution. To date, EO polymer modulators have shown outstanding performance such as high data rate transmission, low-power consumption, and easy integration to other substrates in a form of thin film polymer modulator, organic-silicon hybrid, or traveling-wave polymer on silicon waveguide. The progress makes the polymer device one of the few possible solutions to realize over 100 Gbaud high-speed signalization. Keywords: Electro-Optic / Polymer / Modulator / On-Off-Keying / Pulse-Amplitude-Modulation / Waveguide / Mach-Zehnder Interferometer |
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