POLYMERS Vol.68 No.8
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COVER STORY
Self-Assembly Creating Novel Functional Nanomaterials
COVER STORY: Highlight Reviews
Toroidal Supramolecular Polymers Keisuke ARATSU, Shiki YAGAI
<Abstract> The “toroid” is one of the most attractive topologies ubiquitously found from the universe to the biological system. However, the bottom-up creation of such toroidal topologies using nanoscale soft materials is a non-trivial challenge. This article describes the creation of toroidal nanostructures through molecular self-assembly, and highlight the functional aspect of such unique topologies.
Keywords: Supramolecular Polymer / Self-Assembly / Toroid / Ring / Topology / Hydrogen Bond
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Advanced Semiconductor Lithography using Directed Self-Assembly of Block Copolymers Tsukasa AZUMA
<Abstract> Novel half pitch (HP) 15 nm and HP 10 nm line pattern multiplication processes with simple process steps and low cost-of-ownership using directed self-assembly (DSA) of lamellar block copolymers (BCPs) were developed in order to carry out process verification of DSA lithography on a 300 mm wafer for practical semiconductor device manufacturing. Electrical yield verification of HP 15 nm and HP 10 nm metal wire circuits fabricated by the HP 15 nm and HP 10 nm line pattern multiplication processes using the DSA of BCPs was carried out on the 300 mm wafer. The electrical yield verification could reveal the viability of the HP 15 nm and HP 10 nm line pattern multiplication processes from a perspective of total practical performance including critical dimension control, defect control, local placement errors, line width roughness, and process windows in pattern transfer process.
Keywords: Semiconductor / Lithography / Directed Self-Assembly / Block Copolymer / Polystyrene-Block-Poly (Methyl Methacrylate) / Metal Wire Circuit / Electrical Yield Verification / Defect
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Development of Structural Color Materials by Colloidal Assembly Hiroshi FUDOUZI
<Abstract> Colloidal crystals with 3D ordered colloidal particles have been manufactured as artificial opals since half a century ago. Two decades ago, colloidal crystals got much attention in applications for photonic crystals. Recently colloidal crystal materials were studied for use in advanced applications as sensors and structural color materials focusing on functionalities in which structural color changes occurs due to external factors. In addition, several groups had been working on mass-product processes for high quality colloidal crystal films by colloidal self-assembly. In this review paper, I will show some cases of Lab to Market for colloidal crystal with structural color materials. In addition, I will explain our project for a strain mapping sheet made of a colloidal crystal film for applications to the civil engineering field.
Keywords: Colloidal Crystal / Photonic Crystal / Structural Color / Tunable Color / Strain Imaging / Self-Assembly / Film Coating / Lab to Market
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COVER STORY: Topics and Products
Molecular Monolayer Nanotubes Naohiro KAMETA
<Abstract> Self-organization of rationally-designed synthetic lipids in water produces nanotubes consisting of monolayer membranes of the lipids. Herein I describe our latest research topics about functionalized nanotubes. (I) Taylor-made nanotube channels are useful for formation of polymers with controlled conformation, size, and chirality. (II) Nanotube liquid crystals, based on side-by-side alignment of nanotubes in water, act as templates for growth of gold seeds to nanorods in the absence of surfactants. (III) Encapsulation of enzymes in photoresponsive transformable nanotube/nanocoil and continuous end capping with magnetic nanoparticles enabled us to construct bioreactors. The bioreactors allow control of enzymatic reactions by light irradiation and exhibit excellent kinetic parameters, reusability and recyclability, stabilization of encapsulated enzymes, and size selectivity for substrates. (IV) Photoresponsive shrinkable nanotubes are able to accelerate duplex formation of dinucleotides and release the duplexes into bulk solution. The squeezing out from the narrow nanotube channels is important for stabilization of the energetically unfavorable hydrogen-bonded base pair between the dinucleotides.
Keywords: Self-Organization / Lipids / Amphiphiles / Monolayer / Supramolecular Nanotubes / Nanochannels / Encapsulation / Release
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Designing with Light for Novel Functionalities of Molecularly Aligned Films Kyohei HISANO
<Abstract> Liquid crystal materials that intrinsically possess nano- to macro-scale ordered structures are the key for developing novel functionalities in the field of mechanics, electronics, and photonics. Furthermore, the arbitrary design of two or more dimensional molecular orientation patterns of liquid crystals enables one to enhance and/or manifest new functionalities. For inscribing and controlling the molecular orientation patterns, light stimulus is the most attractive choice due to its high spatiotemporal resolution and remote influence. Here, I introduce advanced techniques to optically control the molecular orientations: one is the common method of photoalignment, and the other is our newly developed method of scanning wave photopolymerization. In addition, I highlight the state-of-the-art trend in photonics applications of a few micrometer-thick polymeric films acting as lenses, prisms, holograms, and polarization converters, and provide some recent examples with two-dimensional molecular orientation patterns.
Keywords: Liquid Crystals / Molecular Orientation / Photoalignment / Photopolymerization / Photonics / Topological Lightwave / Diffractive Waveplate / Mechanics
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Soft Materials Construction Based on Self-assembly of Filamentous Viruses Toshiki SAWADA
<Abstract> Regularly assembled structures in a controlled manner provide notable excellent properties with great potentials in many fields, including nanotechnology and material science. Especially, biomolecular-based assemblies exhibit better control due to their monodispersity, and are utilized in diverse material fields. Recent studies have revealed that viruses such as filamentous M13 bacteriophages (M13 phages), with a specific affinity for artificial materials or biomolecules, can be utilized to produce various soft materials. Such materials composed of regularly assembled phages are described. It was found that functionalization through genetic engineering and liquid crystal formation-based regular orientation of M13 phages enabled their assemblies to be utilized as soft materials components.
Keywords: Filamentous Virus / M13 Bacteriophage / Phage Display / Liquid Crystal / Genetic Engineering
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Polymer Science and I: A Personal Account
My Starting Point and Experimenting with Synchrotron Radiation X-ray Scattering Mina SAKURAGI
<Abstract> In this article, I will describe the incident that occurred during my maternity leave that sparked my interest in, and lead to my research focus on microemulsions for transdermal drug delivery systems via X-ray scattering. Performing this important research while maintaining work/life balance has been a challenge yet fulfilling.
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Front-Line Polymer Science
Recent Trends on Synthesis of Functional Polymer Particles Taro OMURA, Hideto MINAMI
<Abstract> Polymer particles are prepared by mainly heterogenous polymerization systems such as emulsion polymerization and dispersion polymerization. Obtained polymer particles have been used as film in many indsturial fields as paints, coatings and adhesives. Nowadays, much attention has been focused on applying them directly as particulate materials for electronics, cosmetics, and biomedical fields. Therefore, the control of particle morphology is essenstial part of functional polymer particles. Generally, polymer particles have spherical shape, however, functional polymer particles such as hollow and non-spherical particles can be prepared by thermodynamic and kinetic methods. Moreover, polymer particles can be used as the building blocks of colloidal structure which generates unique optical, rheological and electrical properties that are expected to have applications in functional devices. In this review, we introduce recent development of synthesis of functinal polymer particles, colloidal strucrure and their applications.
Keywords: Polymer Particles / Morphology / Particle Shape / Colloidal Structure / Biopolymer
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