• Title/Summary/Keyword: Engineering polymer

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Study on Electro-opt ic Characteristics in the Optically Compensated Splay Cell with UV-curable Reactive Mesogen

  • Kim, Seong-Su;Jeon, Eun-Jeong;Lee, Myong-Hoon;Lee, Seung-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.327-329
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    • 2008
  • We have studied the optically compensated splay (OCS) mode using reactive mesogen monomer to reduce critical voltage, setting voltage and phase transition time from initial bend to splay state. The high pretilt angle from vertical alignment was formed through the polymerization of UV curable RM monomer at the surfaces. In this way, orientation of the LC with OCS can be achieved without setting voltage.

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Numerical Analysis of Cyclic Deformation of Polymer Foam Film Using Stretched Truncated Octahedron Model (모서리가 제거된 팔면체 인장모델을 이용한 다공성 폴리머 박막의 반복변형거동 수치해석)

  • Yoo, Ui-Kyung;Lee, Young-Seog
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.3
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    • pp.104-110
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    • 2010
  • Cyclic deformations of polymer foam film are simulated using the finite element method. Material of polymer foam film is polypropylene (PP). The calculated polymer foam film is micro-scale thin film has cellular structure. The polymer foam film is used in ferro-electret applications. The polymer foam film is idealized to one cell structure as lens shaped stretched truncated octahedron model. Cyclic deformation is performed by uniaxial stretching. Stretching direction is perpendicular to plane of cellular film. Various cyclic strain amplitudes, pore wall thicknesses, pore shape are investigated to find deformation tendency of cellular structure. Consequently, cellular structure has various macroscopic stresses on cyclic deformation with various pore thickness and pore shape.

Versatile Strategies for Fabricating Polymer Nanomaterials with Controlled Size and Morphology

  • Yoon, Hyeon-Seok;Choi, Moon-Jung;Lee, Kyung-Jin;Jang, Jyong-Sik
    • Macromolecular Research
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    • v.16 no.2
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    • pp.85-102
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    • 2008
  • The development of reliable synthetic routes to polymer nanomaterials with well-defined size and morphology is a critical research topic in contemporary materials science. The ability to generate nanometer-sized polymer materials can offer unprecedented, interesting insights into the physical and chemical properties of the corresponding materials. In addition, control over shape and geometry of polymer nanoparticles affords versatile polymer nanostructures, encompassing nanospheres, core-shell nanoparticles, hollow nanoparticles, nanorods/fibers, nanotubes, and nanoporous materials. This review summarizes a diverse range of synthetic methods (broadly, hard template synthesis, soft template synthesis, and template-free synthesis) for fabricating polymer nanomaterials. The basic concepts and significant issues with respect to the synthetic strategies and tools are briefly introduced, and the examples of some of the outstanding research are highlighted. Our aim is to present a comprehensive review of research activities that concentrate on fabrication of various kinds of polymer nanoparticles.

Characterization of Mechanical Property Change in Polymer Aerogels Depending on the Ligand Structure of Acrylate Monomer

  • Lee, Kyu-Yeon;Jung, Hae-Noo-Ree;Mahadik, D.B.;Park, Hyung-Ho
    • Journal of the Microelectronics and Packaging Society
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    • v.23 no.3
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    • pp.15-20
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    • 2016
  • In an effort to overcome the weakness of aerogel, polymer aerogels have been prepared by copolymerizing the different types of monomers through sol-gel process. Polymerizing the successive phase of a high internal phase emulsion, which has interconnected porous structure, porous polymer aerogel can be manufactured. In this paper, we use the styrene/divinylbenzene chain as a basic monomer structure, and additionally use 2-ethylhexyl methacrylate (2-EHMA) or 2-ethylhexyl acrylate (2-EHA) as monomers for distinguishing the visible mechanical properties of synthesized polymer aerogel. We can observe the different tendency of polymer aerogels by kinds of monomer or ratio. Flexibility and microstructure can be changed by the types of monomer. EHA polymer aerogel shows high flexibility and thin microstructure, and EHMA polymer aerogel shows high hardness and thick microstructure. EHA/EHMA polymer aerogel shows the intermediate nature between them. By utilizing the mechanical properties of three types of polymer aerogels to adequate situation or environment, polymer aerogels could be used as drug agent, ion exchange resin, oil filter and insulator, and so on.

Supramolecular Nanomaterials Derived from Self-Assembly of Dendritic Building Blocks

  • Park, Chi-Young;Lee, Sang-Wha;Lim, Ji-No;Lim, Moon-Seob;Kim, Chul-Hee
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.91-92
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    • 2006
  • The fine-tuned dendrons provide unique supramolecular self-assemblies in various environments such as in water, organic media, and solid-liquid interfaces. They form nanotubes, vesicles, thin films, columns, lamellar nanoribbons depending on the condition of self-assembly process. Unique characteristics of self-assembly of the amide dendrons are described. In addition, elucidation of the structural correlation between the building blocks and the assemblies, stabilization of assembled structure, and transformation of supramolecular assemblies by using external stimuli. Particular emphasis is placed on the formation of cyclodextrin-covered organic nanotubes derived from self-assembly of amide dendrons and their supramolecular transformation. Finally, unique biosensory characteristics of the self-assembled nanotubes will be discussed.

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Progress of Study on Mesogen-Jacketed Liquid Crystalline Polymers at Peking University

  • Fan, Xing-He;Chen, Xiao-Fang;Wan, Xin-Hua;Chen, Er-Qiang;Zhou, Qi-Feng
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.90-90
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    • 2006
  • Mesogen-Jacketed Liquid Crystalline Polymers, MJLCPs, are polymers with mesogenic side groups directly attached to main-chains without using flexible connecting spacers and are able to form liquid crystalline structures. Later work on structure-property of the polymers revealed that the side groups are not necessarily mesogenic for the polymers to form a mesophase so long as that the side groups are directly attached to the backbones and the side groups are large enough. Because of its inherent chain stiffness and that the monomers of MJLCPs are readily polymerizable by "living" free radical polymerizations, MJLCP offered a unique handy tool for making block copolymers. In addition, MJLCP offered also new opportunities for novel functional materials.

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