• Title/Summary/Keyword: Fluorinated surface

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Gradient Structure and Surface Property of Fluorinated Polyacrylate and Polyurethane Latex Blend Films (불소화 폴리아크릴레이트-폴리우레탄 라텍스 혼성필름의 그레디언트 구조와 표면성질)

  • Zhu, Min;Chen, Kun;Zhang, Yufang;Wang, Xiangrongm;Zhou, Xiangdong
    • Polymer(Korea)
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    • v.38 no.3
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    • pp.265-271
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    • 2014
  • In order to investigate the characteristics of the gradient fluorinated polyacrylate and polyurethane latex blend films, the fluorinated polyacrylate emulsion and the polyurethane emulsion were synthesized, and then the both emulsions were blended at a series of ratios. The effects of content of the fluorinated polyacrylate on the gradient structure and surface property of the blended films were assessed by AFM, XPS, SEM-EDX and surface free energy measurements. It appeared that, while the content of the fluorinated polyacrylate latex was up to 30%, the fluorinated polyacrylate particles were selectively gathered on the film-air (F-A) and film-glass (F-G) interfaces at room temperature. When the content of the fluorinated polyacrylate was under 30%, the gradient structure of fluorinated component was not evident. The further increasing of fluorinated polyacrylate in the mixed system facilitated the formation and enlargement of gradient structure, but the adhesion of film decreased a little.

Textile Surface Modification by Environmentally Friendly Waterborne Fluorinated Acrylate Copolymer (환경친화형 수분산성 불소 아크릴레이트 공중합체에 의한 섬유 표면개질)

  • Yoo Su-Yong;Kim Jung-Du;Moon Myung-Jun;Suh Cha-Su;Ju Chang-Sik;Lee Min-Gyu
    • Journal of Environmental Science International
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    • v.13 no.10
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    • pp.947-953
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    • 2004
  • Waterborne fluorinated acrylate copolymer (WFAC) for surface modification of textile was synthesized from perfluoroalkyl ethyl acrylate, octadecyl acrylate, glycidyl methacrylate, surfactant and 3,3 methyl-methoxy butanol. The structures of the synthesized WFAC were determinated by FT-IR and $^{19}F-NMR$ analysis. The thermal stability investigated with DSC and TGA was decreased with increasing the content of fluorinated acrylate in the copolymer. However, the particle sizes of WFAC were increased with increasing the content of fluorinated acrylate in the copolymer. The surface energies calculated by contact angles of WFAC were in the range of 29.80$\~$13.41 dyne/cm. On the observing SEM of the textile surface treated with WFAC, the textile was swollen and compacted with increasing the concentration of water repellency agent. WFAC synthesized in this study showed a good water repellency.

Effect of surface treatments on Single-walled Carbon nanotubes(SWNTs) for Hydrogen storage (수소저장용 단일벽 탄소나노튜브의 표면처리 효과)

  • Lee, Young-Seak;Cho, Se-Ho;Park, Il-Nam
    • Transactions of the Korean hydrogen and new energy society
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    • v.16 no.4
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    • pp.343-349
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    • 2005
  • In this study, We had surface-treated single-walled carbon nanotubes (SWNTs) for improving hydrogen storage capacity. The SWNTs were treated by heat treatment, acid treatment and fluorinated at various temperatures. The SWNTs were characterized by Raman spectroscopy and TEM and estimated hydrogen storage capacities at 303K. As shown Raman spectra and TEM images, the structure of fluorinated SWNTs were stable at 423K but changed to the MWNTs-like structure or onion structure over 523K. Hydrogen storage capacity of SWNTs fluorinated at 423K was remarkably increased 2.6 times than that of pristine SWNTs. For SWNTs fluorinated at 573K, the amount of hydrogen adsorbed wasn't increased compared with SWNTs fluorinated at 423K. Therefore, high hydrogen storage capacity of SWNTs could be archived by fluorinated condition at 423K, which was not changed SWNT structure.

Anisotropic Superomniphobic Wettability on Hierarchical Structures of Micro Line Array Combined with Fluorinated Wax (C24F50)

  • Jeon, Deok-Jin
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.209.2-209.2
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    • 2014
  • In recent years, researches about hydrophobic and hydrophilic surfaces have been executed however their other effects have not been researched enough. In this paper, the fabrication method of hierarchical structures of micro line array combined with fluorinated wax for anisotropic superomniphobic wettability is presented. We have achieved anisotropic and superomniphobic surface via simple two step methods, which are maskless photolithography and wax deposition. In order to prove how to provide those characteristics, SEM, contact angle measurement tool and X-ray diffraction are used. Fluorinated wax is crystalized self-assembly and it is subordinated on micro line array so that it is able to display anisotropic wettability. Understanding on anisotropic superomniphobic surface and simple fabrication method has been attracted to apply for lots of applications which range from self-cleaning surface, microfluidic chip, to directionally fluid control device, even in oily fluid.

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Preparation of bi-polar membranes and their application to hypochlorite production

  • Kim, Jung Sik;Cho, Eun Hye;Rhim, Ji Won;Park, Chan Jong;Park, Soo-Gil
    • Membrane and Water Treatment
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    • v.6 no.1
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    • pp.27-42
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    • 2015
  • In this study, poly (phenylene oxide) (PPO) and poysulfone (PSf) were sulfonated and aminated respectively. Both sulfonated poly (phenylene oxide) (SPPO) and aminated polysulfone (APSf) were characterized via the measurement of FT-IR, swelling degree, ion exchange capacity (IEC), and ion conductivity. Then the surfaces of these membranes were modified by surface fluorination using 2000 ppm $F_2$ gas against $N_2$ gas for 1 h at room temperature. The surface fluorinated SPPO and APSf membranes were characterized again to determine any differences between the pristine and fluorinated membranes. In total, 3 types of bi-polar membranes were prepared by varying the IEC of the APSf and having a fixed value for the IEC of the SPPO. The hypochlorite concentration generated by using the surface fluorinated membranes was dependent on the IEC of the APSf and ranged from 683 to 826 ppm, while there was a considerable improvement in the durability of the surface fluorinated membranes as they remained intact even after operating for 4 h.

Effect of Fluorination on Electrical Behaviors of Carbon Blacks-filled HDPE Polymeric Switch

  • Seo, Min-Kang;Park, Soo-Jin
    • Bulletin of the Korean Chemical Society
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    • v.30 no.6
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    • pp.1337-1340
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    • 2009
  • Electrical properties of a fluorinated carbon black (CB)-filled high-density polyethylene (HDPE) polymeric switch were investigated as a function of fluorination pressure at 0.1 ~ 0.4 MPa. From the FT-IR results, the absorption spectra of the fluorinated CB show an absorption band at 1400 ~ 1000 $cm^{-1}\;for\;{\nu}_{C-F}$ and the peak intensity increased with increasing fluorination pressure. Also, the analysis of XPS spectra of the fluorinated CB indicated that fluorine content increased with increasing fluorination pressure. Meanwhile, the surface free energy of the fluorinated CB decreased with increasing fluorination pressure. Consequently, the increase of fluorine contents of CB made a disappearance of negative temperature coefficient (NTC) behavior of the polymeric switch, which was probably due to the reduction of CB reaggregation after melting point of the HDPE, resulted from the decreasing of London dispersive component of the surface free energy for CB particles.

Synthesis of Non-fluorinated Polystearyl methacrylate Water Repellent and Its Properties on Textile Fibers (비불소계 폴리스테아릴메타크릴레이트 발수제의 합성과 발수특성)

  • Kim, Taekyeong;Kang, Hyejin;Park, Jihoon
    • Textile Coloration and Finishing
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    • v.29 no.2
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    • pp.55-61
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    • 2017
  • A non-fluorinated polystearyl methacrylate water repellent was synthesized by emulsion polymerization. The number and weight averaged molecular weights were obtained at around 137,277 and 237,754g/mole. The melting point was observed at $32^{\circ}C$. The contact angle of water droplet on fabrics treated with the water repellent was $140{\sim}145^{\circ}$ for cotton and polyester, and $125{\sim}130^{\circ}$ for wool and nylon. Since the critical surface tension was estimated at 20.7mN/m, even though relatively not so strong as fluorinated water repellent, it is considered to be used as a good water repellent practically.

Fabrication of the Superhydrophobic Surface Inspired from Lotus-Effect (연꽃잎을 모사한 초소수성 표면 제작)

  • Jung, Dae-Hwan;Lim, Hyun-Eui;Noh, Jeong-Hyun;Kim, Wan-Doo
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.409-414
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    • 2007
  • Wettability of solid surfaces with liquids is governed by the chemical properties and the microstructure of the surfaces. We report on the preparation of liquid-repellent surfaces using surface-attached monolayers of perfluorinated polymer molecules on porous silica substrates. A covalent attachment of the polymer molecules to the substrate is achieved by generation of the polymer chains through starting a surface-initiated radical-chain polymerization of a fluorinated monomer. To this, self-assembled monolayers of azo initiators are attached to silica substrates, which are used to kick off the polymerization reaction in situ. The growth of the fluorinated polymer films and the characterization of the obtained surfaces by surface plasmon spectroscopy, XPS, and contact angle measurements is described. It is shown that perfluorinated polymer films can be grown with controlled thicknesses on flat and even on porous silica surfaces, essentially without changing the surface roughness. The combination of the low surface energy coating and the surface porosity allows generation of materials which are both water and oil repellent.

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Dispersion stability of polyelectrolyte-wrapped carbon black particles in a highly fluorinated solvent

  • Yoon, Hyeon Ji;Choe, Jun Ho;Jin, Hyoung-Joon
    • Carbon letters
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    • v.26
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    • pp.25-30
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    • 2018
  • The dielectric medium used in electrophoretic displays (EPDs) is required to be an environmentally friendly solvent with high density, low viscosity, and a large electric constant. Hydrofluoroether, a highly fluorinated solvent with eco-friendly characteristics, is regarded as a viable alternative medium for EPDs, owing to the similarity of its physical properties to those of the conventional EPD medium. Surface modification of particles is required, however, in order for it to disperse in the charged solvent. Also, positive/negative charges should be present on the particle surface to enable electrophoretic behavior. In this study, carbon black particles wrapped with positively charged nitrogen (N-CBs) were fabricated by a simple hydrothermal process using a poly(diallyldimethylammonium chloride) solution as a black coloring agent for the EPD. The dispersion behavior of N-CBs was investigated in various solvents.

Synthesis of Fluorinated Polymer Gate Dielectric with Improved Wetting Property and Its Application to Organic Field-Effect Transistors

  • Kim, Jae-Wook;Jung, Hee-Tae;Ha, Sun-Young;Yi, Mi-Hye;Park, Jae-Eun;Kim, Hyo-Joong;Choi, Young-Ill;Pyo, Seung-Moon
    • Macromolecular Research
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    • v.17 no.9
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    • pp.646-650
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    • 2009
  • We report the fabrication of pentacene organic field-effect transistors (OFETs) using a fluorinated styrene-alt-maleic anhydride copolymer gate dielectric, which was prepared from styrene derivatives with a fluorinated side chain [$-CH_2-O-(CH_2)_2-(CF_2)_5CF_3$] and maleic anhydride through a solution polymerization technique. The fluorinated side chain was used to impart hydrophobicity to the surface of the gate dielectric and maleic anhydride was employed to improve its wetting properties. A field-effect mobility of 0.12 cm$^2$/Vs was obtained from the as-prepared top-contact pentacene FETs. Since various functional groups can be introduced into the copolymer due to the nature of maleic anhydride, its physical properties can be manipulated easily. Using this type of copolymer, the performance of organic FETs can be enhanced through optimization of the interfacial properties between the gate dielectric and organic semiconductor.