Meso-scale Order Structure Prepared From Immiscible Polymer Blend Solutions
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Meso-scale Order Structure Prepared From Immiscible Polymer Blend Solutions Junhyeok Jang1, Tsuyoshi Inoue1, Masayuki Kawazoe2 and Hirohisa Yoshida1 1 Department of Applied Chemistry, Graduate School of Urban Environmental Science, Tokyo Metropolitan University, 1-1 Minami-Osawa Hachioji Tokyo 192-0397, Japan 2 Research Center, Yokohama Rubber Co. Ltd. Oiwake, Hiratsuka, Kanagawa, Japan ABSTRACT The meso-scale hexagonally packed order structures were obtained by solvent casting from the immiscible polymer blend solutions. The order structures were the result of phase separation occurred at the evaporation front during the solvent casting, the so-called dissipative system. The order domains were flat spheres or ellipses on the matrix surface depending on the combination of polymer blends and solvent, the diameter of spheres were tunable from 0.5 to 3 μm by the casting condition, such as the solvent used for mixing and the evaporation rate. Three blend systems, NBR/SBR, NBR/BR and PMMA/BR, formed two dimensional order structures with the domain size in μm-scale by solvent casting from those homogeneous solutions. The conditions to obtain the two dimensional meso-scale order structure were evaluated. INTRODUCTION Meso-scale (100 nm to 10 μm) is the border range obtained by the bottom-up and top-down methods. A representative of top-down method is optical lithography used to create patterns of semi-conductor. The minimum size is determined by the wavelength of light used for lithography, the realized size reaches 40 nm1, 2). Also, the nano-imprint and the micro contact print are classified in the top-down method. The bottom-up method, which designs a material by stacking or self-assembling atoms or molecules by controlling the intermolecular interaction, includes self-assemble surfactant solutions and block copolymers. The prior research of bottom-up methods has been reported to design regular array structure by the micro phase separated structure of block copolymer3, 4). Two types of order structure are known for the polymer based functional materials, such as a thermodynamic equilibrium nm-scale structure and a dissipative μm-scale structure. The dissipative structure forms under chemical and physical dynamic conditions far from the equilibrium. Several regular patterns, such as the spirals in the Belousv-Zhabotinsky reaction, the stripes in the Rayleigh-Benard convections, nano-particles alignment by solvent casting from polymer solution and the fingering patterns at the liquid interface, are reported5). The meso-scale range is demonstrated by the aggregation of molecules which includes liquid crystals, polymers, amphiphilic molecular assembly and colloid. The honeycomb structure, which fabricates twodimensional direction regular array of condensation water droplets of uniform diameter occurring in the process of solution casting of polymer film, has also been noted6-8). Further, the meso-scale regular structure of polymer blend has been reported, such as the honeycomb film forming method9). In this study, we investi
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