• Title/Summary/Keyword: mesoscopic ordering

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Synthesis and Characterization of Co-Surfactant Templated Mesoporous Materials with Enhanced Hydrothermal Stability

  • Kim Geon-Joong;Kim Hyun-Seok;Ko Yoon Soo;Kwon Yong Ku
    • Macromolecular Research
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    • v.13 no.6
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    • pp.499-505
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    • 2005
  • Ordered mesoporous materials with a hydrothermally-stable, protozeolitic framework were prepared by exploring the direct conversion of inorganic species based on co-surfactant templating systems. To confer hydrothermal stability on the mesoporous aterials, the organic-inorganic hybrids were heat-treated in strongly basic media. Co-surfactant templating systems of cetyltrimethylammonium bromide [$C_{16}H_{13}(CH_{3})_{3}$NBr, CTAB] with 1,3,5-trim­ethylbenzene (TMB) or a nonionic block copolymer of poly(ethylene oxide )-b-poly(propylene oxide )-b-poly(ethyl­ene oxide) ($EO_{20}PO_{70}EO_{20}$) were employed to improve the hydrothermal stability of the organic-inorganic self-assembly during the solid rearrangement process of the inorganic species. The mesoscopic ordering of the pore structure and geometry was identified by X-ray diffraction, small angle neutron scattering and electron microscopy.

Simulations of Self-Assembled Structures in Macromolecular Systems: from Atomistic Model to Mesoscopic Model (고분자 자기조립 구조의 전산 모사: 원자 모델로부터 메조 스케일 모델까지)

  • Huh, June;Jo, Won-Ho
    • Polymer(Korea)
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    • v.30 no.6
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    • pp.453-463
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    • 2006
  • Molecular simulation is an exceptionally useful method for predicting self-assembled structures in various macromolecular systems, enlightening the origins of many interesting molecular events such as protein folding, polymer micellization, and ordering of molten block copolymer. The length scales of those events ranges widely from sub-nanometer scale to micron-scale or to even larger, which is the main obstacle to simulate all the events in an ab initio principle. In order to detour this major obstacle in the molecular simulation approach, a molecular model can be rebuilt by sacrificing some unimportant molecular details, based on two different perspectives with respect to the resolution of model. These two perspectives are generally referred to as 'atomistic' and 'mesoscopit'. This paper reviews various simulation methods for macromolecular self-assembly in both atomistic and mesoscopic perspectives.

Thermally Induced Mesophase Development in Ethanesilica Films via Macromolecular Templating Approach

  • Cho, Whirang;Char, Kook-Heon;Kwon, Su-Yong
    • Macromolecular Research
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    • v.17 no.9
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    • pp.697-702
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    • 2009
  • Mesoporous ethanesilica thin film was prepared using PEO-PLGA-PEO triblock copolymers as structure-directing agents and (1,2-bis(triethoxysilyl) ethane BTESE; bridged organosilicates) as inorganic precursors via one-step sol-gel condensation of ethanesilica precursors. The mesostructure of ethanesilica films is critically dependent on the processing experimental parameters after the hydrolyzed silica sol mixture was spin-cast. This study examined the effects of the block copolymer template/organosilica precursor ratio in the casting solution and aging period before calcination of the mesostructure. It was further demonstrated that mesoscopic ordering of organosilicate thin films is induced by the rearrangement of block copolymer template/organosilica hybrid during thermal decomposition of the PEO-PLGA-PEO triblock copolymer. The mesoporous structure and morphology were characterized by SAXS, TEM and solid-state NMR measurement.