高分子 Vol.70 No.11
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特集 伝わる、伝える高分子
展望 COVER STORY: Highlight Reviews
Metallic Plastic Mediated by Ion Exchange Doping
山下 侑・渡邉 峻一郎
<要旨> 半導体材料を電子デバイスとして利用する際には、化学ドーピングを行い電子の数を制御する必要がある。本研究では、高分子の結晶構造に存在する周期的な空隙に着目し、「イオン交換」現象を用いて、化学ドーピングを精密に制御することに成功した。これによって高分子中の電子が金属中の自由な電子のように振る舞うことが明らかとなった。
Keywords: π-Conjugated Polymers / Chemical Doping / Ion Exchange / Metallic Conduction
MOF Glass and Liquid for Electric/Ionic Conductivity
堀毛 悟史
Satoshi HORIKE
<要旨> 近年、金属伝導や高速イオン伝導を示す金属-有機構造体(Metal-organic framework,MOF)の結晶構造が次々と設計、合成されている。また最近では結晶の一部が融解し、その融液を冷却することによるMOFガラスも報告され、エレクトロ/イオニクスデバイスに実装しうるアモルファス材料として注目を集めている。ガラスや融液に内在する高次構造と伝導機能について紹介する。
Keywords: Ion Conductivity / Electric Conductivity / Metal-Organic Frameworks / Coordination Polymers / Glass / Functional Liquid / Mechanical Property / Fuel Cell
Transmitting Heat by Controlling Higher Order Structures of Polymers
竹澤 由高
Yoshitaka TAKEZAWA
<要旨> 高分子は優れた絶縁材料であるが基本的に断熱性であり、熱を伝えにくい。近年、高次構造を制御することで熱可塑性高分子の熱伝導率を金属並みに向上させた報告や、電子機器に使われる熱硬化性高分子の異材間の熱伝達に効果的な接着界面における分子配列制御も見いだされつつある。これらの新たな熱を伝える高次構造制御技術を取り上げて紹介する。
Keywords: Higher Order Structure / Phonon / Thermal Conductivity / Molecular Orientation / Mesogen / Epoxy / Polyethylene
トピックス COVER STORY: Topics and Products
Hydrogen-Bonding Conductive Polymer Electrocatalysts for Conversion and Storage of Renewable Electricity
原田 祐弥・吉田 司
<要旨> Metal-free hydrogen-bonding conductive polymer electrocatalysts (HCPCs) are promising and sustainable candidates for conversion of renewable electricity into storable chemical energies to be used on demand. This article gives a short review on our recent explorations for the HCPCs. While the π-conjugated system of the polymer main chain affords electrical conductivity, the presence of hydrogen-bonding substituents are also essential for stabilization of reaction intermediates to exhibit electrocatalytic activities for the hydrogen evolution reaction (HER) and the CO2 reduction reaction (CO2RR). Such HCPCs are obtained either by oxidative chemical vapor deposition or electropolymerization deposition. Taking poly-dopamine (PDA) as an example, the reasons for selectivities of HER and CO2RR are discussed to project possible future challenges to obtain useful hydrocarbons as products.
Keywords: Hydrogen Bonding Conductive Polymer Catalysts (HCPC) / Electrocatalysis / Energy Conversion / Hydrogen Evolution Reaction/ CO2 Reduction Reaction
Development of 3D Gyroid-Nanostructured Proton Conduction Pathway
一川 尚広・小林 翼
<要旨> In situ polymerization of liquid-crystalline monomers in the self-assembled states is a unique strategy for creating highly-ordered-nanostructured polymer membranes. We have focused on the use of this strategy for developing gyroid nanostructured polymer films having a 3D continuous proton conduction pathway. A gemini-type amphiphile zwitterion monomer has been designed and synthesized. It forms bicontinuous cubic phases in the presence of appropriate amounts of bis(trifluoromethanesulfonyl)imide and water. By carrying out polymerization for the mixture in the liquid-crystalline state, a gyroid nanostructured polymer film with self-standing properties has been obtained. It shows a high ionic conductivity on the order of 10-1 S cm-1 when it is placed under high relataive humidity of 90%. The high ionic conductivity can be attributed to the formation of a proton hopping conduction pathway that is composed of hydrogen-bonding networks of water molecules along a gyroid minmal surface.
Keywords: Gyroid / Bicontinuous Cubic Phase / Liquid Crystal / Self-Organization / Proton Conduction
二・三次元 電子・イオン伝導性材料
2D, 3D Electron and Ionic Conductive Materials
池田 太一
Taichi IKEDA
<要旨> This article introduces two-dimensional electron conductive materials so-called “thiophene nanosheets” and ion conductive materials based on cationic glycidyl triazolyl polymers (cationic GTPs) with three-dimensional branched side chains. Thiophene nanosheets are made from foldable polymers consisting of phenyl-capped bithiophene, oligo(ethylene glycol) and turning units via intra- and inter-molecular self-assemblies. Thiophene units form two-dimensional crystals sandwiched by ethylene glycol layers, which can exhibit comparable carrier mobility as that observed in thiophene film prepared by vacuum vapor deposition. Cationic GTPs are synthesized using copper-catalyzed azide-alkyne cycloaddition (Cu-AAC) between glycidyl azide polymer and alkyne derivatives of ionic liquids. Thanks to the high reactivity of Cu-AAC, poly(ionic liquid)s with branched side chains were successfully prepared. It was confirmed that the glass transition temperature decreases and the ionic conductivity increases with increasing the degree of the side chain branching. In case of cationic GTP with tri-branched side chains, the highest ionic conductivity of 3.6×10-5 S/cm was recorded (at 298 K, anhydrous condition).
Keywords: 2D Materials / Functional Polymers / Self-Assembly / Foldamer / Poly(Ionic Liquid)s / Ion Conductive Materials / Polyelectrolytes / Glycidyl Polymer
Phase-Change Materials Using Plastic Crystals
中 建介
Kensuke NAKA
<要旨> Phase-change materials (PCMs) have drawn great interest in the past few decades due to their capability of absorbing and releasing latent heat within a narrow temperature interval during phase change. The design of molecular alloys using n-alkanes are often used for this purpose. Encapsulation of this system constitutes an efficient way to prevent the leakage of melted PCMs. We found that mono-functionalized heptaisobutyl-substituted polyhedral octasilsesquioxane (POSS) derivatives (R-POSSs) exhibited orientationally disordered (OD) phase transition depending on their substitutions. The tested POSS derivatives showed variable sharp endothermic peaks between -29 to 60℃. The composite films were prepared by drop-casting of a chloroform solution of PMMA with R-POSS. No appearance change of films was observed despite the heating and cooling of the films on the hotplate due to no drastic density difference below and above the OD phase transition. This result suggests that the isobutyl-substituted POSS derivatives are expected to be good candidates for PCMs.
Keywords: POSS / Orientationally Disordered Phase / Plastic Crystals / Silsesquioxane / Phase-Change Materials
グローイングポリマー Polymer Science and I: A Personal Account
Try Something New to Build Strengths
西村 智貴
<要旨> The author has worked in different research fields at three different universities. He feels that challenging himself in new research fields has built up the author’s strengths as a researcher. In this column, he will introduce his past research experience and show the importance of taking on new challenges.
高分子科学最近の進歩 Front-Line Polymer Science
Polymers and Supramolecules with Helical or Twisted Conformation
中野 環
<要旨> Polymers and supramolecules with helical or twisted conformation are reviewed focusing on construction of novel chemical structure and conformational control over existing chain structure as well as novel applications and analytical methodologies.
Keywords: Circular Dichroism / Catalysis / π-Stack / Cyclopolymerization / Circularly Polarized Light / Covalent Organic Framework / Aggregation / Polymer Reaction