• Title/Summary/Keyword: Surface organic chemistry

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Organic Nanotube Induced by Photocorrosion of CdS Nanorod

  • Choi, Sung-Won;Yoon, Joong-Ho;An, Myoung-Jin;Chae, Won-Sik;Cho, Hyeon-Mo;Choi, Moon-Gun;Kim, Yong-Rok
    • Bulletin of the Korean Chemical Society
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    • v.25 no.7
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    • pp.983-985
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    • 2004
  • PMMA-coated CdS nanorod was prepared by encapsulation of CdS nanorod through the polymerization process of PMMA on the surface of CdS nanorod. PMMA organic nanotube was then obtained from the elimination of the CdS nanorod by the photocorrosion. For the photocorrosion reaction of the CdS nanorod, monochromatic light was irradiated to the oxygen-saturated aqueous methyl viologen solution with PMMAcoated CdS nanorod. Photocorrosion reactions of PMMA-coated CdS nanorod were investigated and characterized by utilizing UV-Vis absorption, X-ray diffraction (XRD) and scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images.

Synthesis and Surface Derivatization of Processible Co Nanoparticles

  • Lee, Jin-Kyu;Choi, Sung-Moon
    • Bulletin of the Korean Chemical Society
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    • v.24 no.1
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    • pp.32-36
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    • 2003
  • Co nanoparticles were prepared by the reverse micelle technique (NaBH₄reduction of cobalt chloride in a reversed micelle solution of didodecyldimethylammoniumbromide (DDAB)/toluene). The size and the shape of Co nanoparticles could be easily controlled by changing the water contents and micelle concentrations, and the solubility of Co nanoparticles was systematically tuned by choosing appropriate surface capping organic ligand molecules. Furthermore, a novel nanofabrication process was clearly demonstrated, which generated oxide over-coated Co nanorods from Co nanoparticles in organic solution by slow oxidation with an external magnetic field.

Heterogeneous SnCl2/SiO2 versus Homogeneous SnCl2 Acid Catalysis in the Benzo[N,N]-heterocyclic Condensation

  • Darabi, Hossein Reza;Aghapoor, Kioumars;Mohsenzadeh, Farshid;Jalali, Mohammad Reza;Talebian, Shiva;Ebadi-Nia, Leila;Khatamifar, Ehsan;Aghaee, Ali
    • Bulletin of the Korean Chemical Society
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    • v.32 no.1
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    • pp.213-218
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    • 2011
  • The scope of homogeneous Lewis acid-catalyzed benzo[N,N]-heterocyclic condensation was expanded to include the use of various metal salts not reported in the literature and $SnCl_2{\cdot}2H_2O$ was finally selected. Among various solid supports activated with $SnCl_2$, heterogeneous $SnCl_2/SiO_2$ proved to be the most effective and significantly higher conversions were achieved compared to $SnCl_2{\cdot}2H_2O$ itself. The results of TG-DTA and BET indicated that dispersed $SnCl_2$ coordinates with surface hydroxyl groups of silica leading to formation of stable Lewis acid sites. Low catalyst loading, operational simplicity, practicability and applicability to various substrates render this eco-friendly approach as an interesting alternative to previously applied procedures.

Improvement of Hard Coating Characteristics by UV-curable Organic/Inorganic Hybrids (자외선 경화형 유기/무기 하이브리드에 의한 하드코팅 특성 향상)

  • Han, Ji-Ho;Kim, Hyung-Il
    • Applied Chemistry for Engineering
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    • v.28 no.6
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    • pp.626-631
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    • 2017
  • Transparent plastic substrates require an improvement in properties such as surface hardness and thermal stability for optical applications. In this study, UV-curable organic/inorganic hybrids were synthesized to improve those properties. In order to make the optimum dispersion of inorganic component into the organic matrix, an in situ synthetic method was applied based on sol-gel reaction. Dispersion of the inorganic component in the organic urethane acrylate matrix was improved by using a proper combination of sol-gel reaction and fast UV-curing resulting in the formation of the transparent coating layer. Various alkoxy silanes were employed to vary both the degree of curing and coating properties of UV-curable organic/inorganic hybrids. UV-cured organic/inorganic hybrid coatings showed an improved surface hardness and thermal resistance depending on the content of inorganic component.

Modeling and Characterization of Steam-Activated Carbons Developed from Cotton Stalks

  • Youssef, A.M.;Hassan, A.F.;Safan, M.
    • Carbon letters
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    • v.14 no.1
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    • pp.14-21
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    • 2013
  • Physically and chemically activated carbons (ACs) exhibited high adsorption capacities for organic and inorganic pollutants compared with other adsorbents due to their expanded surface areas and wide pore volume distribution. In this work, seven steam-ACs with different burn-off have been prepared from cotton stalks. The textural properties of these sorbents were determined using nitrogen adsorption at $-196^{\circ}C$. The chemistry of the surface of the present sorbents was characterized by determining the surface functional C-O groups using Fourier transform infrared spectroscopy, surface pH, $pH_{pzc}$, and Boehm's acid-base neutralization method. The textural properties and the morphology of the sorbent surface depend on the percentage of burn-off. The surface acidity and surface basicity are related to the burn-off percentage. A theoretical model was developed to find a mathematical expression that relates the % burn-off to ash content, surface area, and mean pore radius. Also, the chemistry of the carbon surface is related to the % burn-off. A mathematical expression was proposed where % burn-off was taken as an independent factor and the other variable as a dependent factor. This expression allows the choice of the value of % burn-off with required steam-AC properties.

Theoretical Studies on Dicyanoanthracenes as Organic Semiconductor Materials: Reorganization Energy

  • Park, Young-Hee;Kim, Yun-Hi;Kwon, Soon-Ki;Koo, In-Sun;Yang, Ki-Yull
    • Bulletin of the Korean Chemical Society
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    • v.31 no.6
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    • pp.1649-1656
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    • 2010
  • Internal reorganization energy due to the structural relaxation in hole or electron hopping mechanism is one of the measurements of key indices in designing an organic thin film transistor (OTFT) for flexible display devices. In this study, the reorganization energies of dicyanoanthracenes for the hole and electron transfer were estimated by adiabatic potential energy surface and normal mode analysis method in order to examine the effect on the energies for the positional variation of the cyano substituents in the anthracene as a protocol of acenes to design an organic field effect transistor. The reorganization energy for the hole transfer was reduced considerably upon cyanation of anthracene, especially at the 9,10-positions of anthracene, and the origin of the reduction was interpreted in terms of understanding the coupling of vibrational modes to the hole transfer.