• Title/Summary/Keyword: block copolymer

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A Pathway to Microdomain Alignment in Block Copolymer/Nanoparticle Thin Films under Electric Field

  • Bae, Joonwon
    • Bulletin of the Korean Chemical Society
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    • v.35 no.9
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    • pp.2689-2693
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    • 2014
  • The control over microstructure in block copolymer thin films using external electric fields has become an interesting research topic. In this article, the effect of nanoparticle on the microdomain alignments in block copolymer (polystyrene-b-poly(2-vinylpyridine)/nanoparticle (Au) thin films under electric fields has been examined with transmission electron microscopy. The homogeneous dispersion of Au nanoparticles into the block copolymer matrix was achieved by surface modification of nanoparticles with compatible ligands. Compared with the phenomenon seen in the pristine block copolymer thin films, a peculiar alignment behavior was observed in the block copolymer/nanoparticle hybrid thin films under electric fields. In addition, the different pathways observed in the pristine and nanoparticle incorporated block copolymer thin films were also monitored as a function of exposure time. This work can provide the fundamental information for understanding microdomain alignment in block copolymer/nanoparticle thin films under external electric fields.

Fabrication of Free-Standing Three-Dimensional Block Copolymer Patterns on Substrate (블록 공중합체 3차원 패턴의 제조 방법 및 그 구조 특성)

  • Choi, Hong Kyoon
    • Korean Journal of Materials Research
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    • v.29 no.12
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    • pp.804-811
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    • 2019
  • As the importance of three-dimensiona (3D) nano patterns and structures has recently emerged, interest in the study of 3D structures of block copolymers has increased. However, most existing studies on block copolymer 3D patterns on substrates are limited to simple 3D structures such as a multi-layered forms. In this study, we propose an experimental method for realizing free-standing 3D block copolymer patterns on substrates using an e-beam lithographic template and film transfer method. The block copolymer 3D structure formed in wide hole templates are similar to simple multi-layered structures; however, as the width of the hole template become narrower, more complex block copolymer 3D structures are formed in which the upper and lower layer structures are interconnected. Furthermore, we introduce a method to fabricate novel block copolymer structures in which the 2D planar structures are connected to 3D complex structures. Proposed 3D block copolymer fabrication method provides a framework for generation of unconventional 3D structures of block copolymer, which can be useful for next generation 3D devices.

Surface modification for block copolymer nanolithographyon gold surface

  • Hwang, In-Chan;Bang, Seong-Hwan;Lee, Byeong-Ju;LeeHan, Bo-Ram;Kim, Hyeong-Jun
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2009.11a
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    • pp.33.2-33.2
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    • 2009
  • Block copolymer lithography has attracted great attention for emerging nanolithography since nanoscaleperiodic patterns can be easily obtained through self-assembly process without conventional top-down patterning process. Since the morphologies of self-assembled block copolymer patterns are strongly dependent on surface energy of a substrate, suitable surface modification is required. Until now, the surface modification has been studied by using random copolymer or self-assembled mono layers (SAMs). However, the research on surface modifications has been limited within several substrates such as Si-based materials. In present study, we investigated the formation of block copolymer on Au substrate by $O_2$ plasma treatment with the SAM of 3-(p-methoxy-phenyl)propyltrichloro-silane [MPTS, $CH_3OPh(CH_2)_3SiCl_3$]. After $O_2$ plasma treatment, the chemical bonding states of the surface were analyzed by X-ray photoelectron spectroscopy (XPS). The static contact angle measurement was performed to study the effects of $O_2$ plasma treatment on the formation of MPTS monolayer. The block copolymer nanotemplates formed on Au surface were analyzed by scanning electron microscopy. The results showed that the ordering of self-assembled block copolymer pattern and the formation of cylindrical nano hole arrays were enhanced dramatically by oxygen plasma treatment. Thus, the oxidation of gold surface by $O_2$ plasma treatment enables the MPTS to form the monolayer assembly leading to surface neutralization of gold substrates.

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Epitaxial Self-Assembly of Block Copolymer Thin Film for Nanofabrication

  • Kim, Sang-Ouk
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.293-293
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    • 2006
  • Self-assembled nanostructures of block copolymer thin films have gathered significant attention due to their potential applications as templates for nanofabrication. However the lack of a robust strategy to control the structure formation in thin film geometries has been considered a major obstacle for the practical application. In this presentation 'epitaxial self-assembly' will be introduced as a successful strategy to control the self-assembled nanostructure of block copolymer. Chemically patterned surfaces prepared by advanced lithographic techniques successfully registered nanodomains in block copolymer thin film without any single defect over an arbitrarily large area.

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The Effect of Nano Functionalized Block Copolymer Addition on the Joint Strength of Structural Epoxy Adhesive for Car Body Assembly (차체 구조용 에폭시 접착제의 접합강도에 미치는 나노 기능성 블록공중합체 첨가의 영향)

  • Lee, Hye-rim;Lee, So-jeong;Lim, Chang-young;Seo, Jong-dock;Kim, Mok-soon;Kim, Jun-ki
    • Journal of Welding and Joining
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    • v.33 no.4
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    • pp.44-49
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    • 2015
  • The structural epoxy adhesive used in car body assembly needs the highest level of joint mechanical strength under lap shear, T-peel and impact peel conditions. In this study, the effect of nano functionalized block copolymer addition on the impact peel strength of epoxy adhesive was investigated. DSC analysis showed that the addition of nano functionalized block copolymer did not affect the curing reaction of epoxy adhesive. From single lap shear test, it was found out that the addition of nano functionalized block copolymer slightly decreased the cohesive strength of cured adhesive layer. The addition of nano functionalized block copolymer showed beneficial effect on T-peel strength by changing the adhesive failure mode to the mixed mode. However, the addition of nano functionalized block copolymer just decreased the room temperature impact peel strength. It was considered that the addition of nano functionalized block copolymer could have effect on disturbing the crack propagation only for the case of slow strain rate.

Polyolefin Block Copolymer Thermoplastic Elastomer (폴리올레핀 블록공중합체 열가소성 탄성체)

  • Koo, Chong Min
    • Korean Chemical Engineering Research
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    • v.46 no.1
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    • pp.15-22
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    • 2008
  • Polyolefin block copolymer has been taking a great deal of attention due to their great potential in polymer industry since a new metallocene catalytic method for producing polyolefin block copolymer was developed by Dow Chemicals. However, so far, there was no systematic study of olefin block copolymer. In this review, Linear polyolefin block copolymers, containing semicrystalline poly (ethylene) (E) blocks and a rubbery block as a thermoplastic elastomer, were investigated in the viewpoint of microphase separation mode, microstructure, deformation behavior, and molecular architecture.

Synthesis of Poly-$N^5$-(3-hydroxypropyl glutamine)/Poly (ethylene glycol)block Copolymer Hydrogel and Its Application to the Artificial Skin (Poly-$N^5$-(3-hydroxypropyl glutamine)/Poly (ethylene glycol)block copolymer hydrogel의 합성과 인공피부에의 응용)

  • 조종수;오상봉
    • Journal of Biomedical Engineering Research
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    • v.12 no.1
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    • pp.57-62
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    • 1991
  • ABA type block copolymers composed of poly($\gamma-benzyl$ L-glutamate) (PBLG) as the A component and poly (ethylene glycol) as the B component were obtained by polymerization of $\gamma-benzyl$ L-gletamate N -carboxyanhydride, initiated by amino groups at both ends of poly(ethylene glycol) . From circular dichroism measurements in ethylene dichloride solution as well as from infrared spectTa measurements in solid state, it was found that the polypep- tide block exists in the a-helical conformation, as in PBLG homopolymer. $Poly-N^5$ (3-hydroxypropyl glutamine) (PHPG)/poly(ethylene glycol)block copolymer hydrogel was obtained by the treatment of PBLG/PBG block copolymer with the mixture of 3-ammine-1-propanol and diamlnooctane. The water content of PHPG/PEG block copolymer hydrogel was about 80wt% when the concentration of crosslinking agent was below 5 mole % per polymer.

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Antithrombogenicity of the Surfacfe of Poly(r-benzyl L-glutamate)/ Poly(ethylene glycol) Block Copolymer (Poly(r-benzyl L-glutamate)/ poly(ethylene glycol) block 공중합체 표면의 항혈전성에 관한 연구)

  • 조종수;송수창
    • Journal of Biomedical Engineering Research
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    • v.8 no.2
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    • pp.199-204
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    • 1987
  • ABA type block copolymers composed of r benzyle L-glutamate as the A component and poly(ethylene glycol) as the B components were obtained. Platelet adhesion on their sunfaces was investigated by a column elusion method to examine the effects of microdomain and secondary structure. The number of platelets adhered from whole blood and plasma rich platelet was smaller for the block copolymer systems than for the homopolymers. In the block copolymer system, the number of platelets adrered on their surfaces increased with increasing the content of PEG, that is, with decreasing of a-helix of block copolymers. A thick thrombus formation on the PBLG homopolymer was observed than block copolymer by scanning electron micrographs. The platelets adhesion increased with increasing the critical surface tension of the block copolymer.

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Block Copolymer Thin Films: Nanotemplates for New Functional Nanomaterials

  • Kim, Jin-Kon;Lee, Jeong-In;Yang, Seung-Yun
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.81-82
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    • 2006
  • In this study, the applications of the block copolymer thin films are introduced. For this purpose, we first obtained cylindrical nanodomains in polystyrene-block-poly(methyl methacrylate) copolymer perpendicularly oriented to a substrate. Then, nanoporous templates were prepared after removing the PMMA nanodomains by UV treatment. By using electropolymerization, high density nanowire arrays of conducting polymer of poly(pyrrole) and poly( 3-hexyl thiopene) were obtained and their electric properties were measured. Also, these nanoporous thin films were found to be very useful for the separation of human Rhinovirus type 14 (HRV 14), major pathogen of a common cold in humans, from the buffer solution.

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Effect of Neutral Solvent on the Phase Behavior of Polystyrene-block-Poly(n-butyl methacrylate) Copolymers

  • Li, Chaoxu;Li, Guang-Hua;Moon, Hong-Chul;Lee, Dong-Hyun;Kim, Jin-Kon;Cho, Jun-Han
    • Macromolecular Research
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    • v.15 no.7
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    • pp.656-661
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    • 2007
  • The effects of a neutral solvent of dioctyl phthalate (DOP) on the phase behavior of symmetric polystyrene-block-poly(n-butyl methacrylate) copolymers (PS-b-PnBMA) were assessed herein. Closed-loop phase behavior with a lower disorder-to-order transition (LDOT) and an upper order-to-disorder transition (UODT) was observed for PS-b-PnBMA/DOP solution when the quantity of DOP was carefully controlled. When the molecular weight of PS-b-PnBMA became larger, the LDOT did not appreciably change at smaller quantities of DOP. With larger quantities of DOP, the reduction in the UODT is greater than the increase in the LDOT. This behavior is discussed in accordance with a molecular theory predicated on a compressible random-phase approximation.