POLYMERS Vol.59　No.7 July 2010

 

POLYMERS　Vol.59　No.7
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COVER STORY
New Trend in Soft Matter
Growing Polymers: A Personal Account
Growing Oligomer Takehiro KAWAUCHI
<Abstract> This personal account is reporting about the author's research life. He would like to express his sincere thanks to former teachers and advisors, who have been demanding and sometimes stubborn, but always cared deeply about science.
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The Core of Technology and Customer Aspects Shinsuke MIYAUCHI
<Abstract> The most important points of achieving good results as an engineer are acquiring a wide range of technological expertise and grasping customer needs appropriately.
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COVER STORY: Highlight Reviews
Liquid Crystals and Polymers Hirotsugu KIKUCHI, Kosuke KANEKO, and Hiroki HIGUCHI
<Abstract> The combination of liquid crystals and polymers yields various novel functions which cannot be obtained by each individual material. Here, we introduce recent work on various kinds of interesting properties resulting from composition of liquid crystals and polymers in a range from the molecular level to macroscopic scale.
Keywords: Polymer / Liquid-Crystal Composite Film / Polymer-Dispersed Liquid Crystal / Liquid Crystal Elastomer / Liquid Crystal Gel / Blue Phase
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Geometrical Models of Amphiphilic Membrane - Polymer Complex Systems Masayuki IMAI
<Abstract> In this review I show geometrical models for amphiphilic membranes - polymer complex systems, polymer confining membranes and polymer grafting membranes. By confining polymer chains between lamellar membrane slits or inside of membrane capsules, the membranes show morphology transitions to optimize the free volume of the polymer chains. On the other hand, amphiphilic copolymer is incorporated into the membrane by anchoring the hydrophobic block of the chain. The hydrophilic tails modify the elastic properties of the membrane and the interactions between membranes. For both cases, the geometrical models describe the observed phenomena well.
Keywords: Polymer / Amphiphilic Membrane / Geometrical Model / Polymer Confining Membranes / Polymer Grafting Membranes / Entropic Interaction / Morphology Transition
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Protein Crystallization Induced by Polyethylene Glycol Shinpei TANAKA
<Abstract> Polyethylene glycol (PEG) is commonly used to crystallize proteins. In this short paper, we review recent understanding about PEG-protein mixtures in terms of protein crystallization. PEG induces an attraction between protein molecules via so-called depletion interaction. The Asakura-Oosawa depletion model gives qualitative descriptions about the interaction between proteins, though quantitatively, it overestimates the attraction. These features are shown using a model system, apoferritin-PEG mixtures. The interactions and the phase diagrams, measured and calculated, are compared. A recent alternative model is briefly reviewed as well. The advantage of PEG as a crystallization reagent is discussed in terms of the protein-protein interaction induced by PEG.
Keywords: Protein Crystallization / Polyethylene Glycol / Depletion Interaction
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Unique Characteristics and Self-Assembling Behavior of Ionic Amphiphilic Block Copolymers Hideki MATSUOKA
<Abstract> Ionic amphiphilic block copolymers show very unique properties and self-assembling behavior, which are largely different from non-ionic polymers and low molecular weight surfactants. Especially, “Non-Surface Activity” is a special characteristic for ionic block copolymers. In addition to this unique molecular property, recent advances in stimuli-responsive nanostructure transition such as micelle/reverse micelle and micelle/vesicle transitions, nanostructure and its transition of polyelectrolyte brushes, novel self-assemblies by polyion complex formation are briefly reviewed.
Keywords: Ionic Amphiphilic Block Copolymer / Non-Surface Activity / Polyelectrolyte Brush / Polymer Micelle / Polyion Complex
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COVER STORY:Topics and Products
Die-Bonding Film Teiichi INADA
<Abstract> Low-modulus die-bonding film is useful for stacked multi-chip packages which are suitable for compact electronic devices. In particular, to cope with the widespread application of very thin semiconductor wafers and Pb-free solders, the films are expected to have both low viscosity in the attaching process and high reliability of bonding in the high temperature reflow process. We studied the phase structure and the property of a new reaction-induced polymer alloy consisting of a low-modulus acrylic polymer and a highly heat-resistant epoxy resin. As a result, this alloy film was clarified to have both high resin flow and good reflow-crack resistance.
Keywords: Polymer Alloy / Epoxy / Acryl / Adhesive
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Polarizer-Free Reflective LCD Using Ultra Low-Power Driving Technology Akio MIYATA
<Abstract> Through refinement of PNLC materials and fabrication conditions, the authors produced a reflective display with reduced flicker and image sticking at low frame rates. The display consumes very little power and works in a wide range of temperatures, making it a potential platform for future mobile devices.
Keywords: Polymer Network Liquid Crystal (PNLC) / Ultra Low-Power Driving Technology / Polarizer-Free Reflective Display
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Phase Separations in Mixtures of a Polymer and a Liquid Crystal Akihiko MATSUYAMA
<Abstract> We introduce our recent theoretical results on phase separations in mixtures of a polymer and a liquid crystal. We here focus on flexible polymer and liquid crystal mixtures and rigid-rod like polymer and liquid crystal mixtures. Phase diagrams of the temperature-concentration plane for these systems are discussed.
Keywords: Phase Separation / Liquid Crystal / Polymer / Liquid Crystal Composite / Polymer Dispersed Liquid Crystal
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Shear-Induced Onion Formation of Surfactant / Triblock Copolymer Mixed Bilayer Lamellar Phase Shuji FUJII
<Abstract> Shear-induced instability of bilayer membrane systems has attracted much attention. One of the most interesting shear effects is a shear-induced lamellar to onion transition. Shear-induced onion formation behavior is quite sensitive to the interaction between grafted polymer chains and surfactant bilayer membranes. Entropy based contribution to the modulus of bilayer controls the onion formation behavior.
Keywords: Surfactant / Lamellae / Onion / Bilayer / Vesicle / Shear-Induced Structure
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Nonequilibrium Depletion Effect by Polymers Masaki SANO
<Abstract> A non-equilibrium depletion effect of colloids was discovered. A local increase of temperature drives the colloids in a polymer solution towards the hot region resulting in trapping of the colloids irrespective of their own thermophoretic properties. We report measurement of this trapping effect with increasing polymer concentration and explain the observation by hydrodynamics.
Keywords: Depletion Force / Nonequilibrium / Soret effect / Micromanipulation / Hydrodynamics
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Front-Line Polymer Science
Elongational Crystallization of Polymers Realizes Ultra-High Performances Kiyoka OKADA and Masamichi HIKOSAKA
<Abstract> We succeeded in bulky elongational crystallization of isotactic polypropylene (iPP) by compressing the supercooled melt. When the elongational strain rate (ε(・)) becomes larger than a critical one (ε(・)* = 2×102 s-1), the crystallization behavior, structure and physical properties changed discontinuously. Morphology changed from well-known spherulites to a novel morphology of “nano-oriented crystals (NOCs)”, the crystallization rate increased by a factor of 106 and the lateral size of crystals decreased by a factor of 10-3 to 20-30 nm. NOC showed a high crystallinity (nearly equal to unity). The above results indicate that the polymer melt changed from isotropic to an oriented melt which accelerated nucleation and growth rates and induced NOC formation. NOC showed ultra-high performances such as high tensile strength, comparable to that of metals, high thermal resistance and so on. NOC will be useful in a wide variety of applications and will contribute to construct a sustainable society.
Keywords: Crystallization / Elongation / Nucleation / Isotactic Polypropylene / Nano / Crystallinity
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