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31.
Varghese N Shetye GS Bandyopadhyay D Gobalasingham N Seo J Wang JH Theiler B Luk YY 《Langmuir : the ACS journal of surfaces and colloids》2012,28(29):10797-10807
Single-chain surfactants usually emulsify and stabilize oily substances into droplets in an aqueous solution. Here, we report a coassembly system, in which single types of anionic or non-ionic surfactants emulsify a class of water-soluble nonamphiphilic organic salts with fused aromatic rings in aqueous solutions. The nonamphiphilic organic salts are in turn promoted to form droplets of water-based liquid crystals (chromonic liquid crystals) encapsulated by single-chain surfactants. The droplets, stabilized against coalescence by encapsulated in a layer (or layers) of single chain surfactants, are of both nonspherical tactoid (elongated ellipsoid with pointy ends) and spherical shapes. The tactoids have an average long axis of ~9 μm and a short axis of ~3.5 μm with the liquid crystal aligning parallel to the droplet surface. The spherical droplets are 5-10 μm in diameter and have the liquid crystal aligning perpendicular to the droplet surface and a point defect in the center. Cationic and zwitterionic surfactants studied in this work did not promote the organic salt to form droplets. These results illustrate the complex interplay of self-association and thermodynamic incompatibility of molecules in water, which can cause new assembly behavior, including potential formation of vesicles or other assemblies, from surfactants that usually form only micelles. These unprecedented tactoidal shaped droplets also provide potential for the fabrication of new soft organic microcapsules. 相似文献
32.
Dihydroxyoligophenylenes (HO-ArPh(m)-OHs) with 9,9-dihexyl-2,7-fluorene (Ar=Flu), 2,5-dioctyloxy-1,4-benzene (Ar=Dob), pyridine (Ar=Py), or thiophene (Ar=Th) rings were synthesized by the Suzuki coupling reaction. Absorption maxima (λmax) of HO-ArPh(m)-OHs shifted progressively toward long wavelengths due to the expansion of the π-conjugation system with an increase in the number of benzene rings. Deprotonation of the OH groups of HO-ArPh(m)-OHs by treatment with NaH caused a bathochromic shift of λmax. The bathochromic shift of the deprotonated species increased with the donor numbers (DNs) of the solvents. The emission peak positions of NaO-ArPh(m)-ONas depended on the DNs of the solvents; therefore, the emission color could be tuned by changing the solvent. 相似文献
33.
Edoardo Magnone Myung Jae Seo Hak Joo Kim Jung Hoon Park 《Journal of Thermal Analysis and Calorimetry》2014,116(1):215-218
The chemical compatibility of perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3?δ (BSCF) oxides with Cr2O3 has been examined between room temperature and 1,100 °C. Differential thermal analysis and thermogravimetric analysis were used to analyze the thermal behavior of BSCF–Cr2O3 binary mixtures in all composition ranges (0–100 mass% BSCF). The reaction products were identified by X-ray analysis after heating at 700–1,100 °C. As we expected, it was found that perovskite-type BSCF oxide had a poor chemical compatibility with the Cr2O3 oxide. In particular, the decomposition process of the BSCF–Cr2O3 binary mixture is quite complex and it starts at about 700–750 °C. The mixtures of BSCF and Cr2O3 oxides reacted forming mixed complex oxides based on (Ba/Sr)FeO3, (Co/Fe)CrO4, and (Ba/Sr)CrO4 mixtures. 相似文献
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36.
Won Seok Seo Youn Jaung Cho Sung Cheol Yoon Joon T. Park Younbong Park 《Journal of organometallic chemistry》2001,640(1-2):79-84
Reaction of ansa-cyclopentadienyl pyrrolyl ligand (C5H5)CH2(2-C4H3NH) (2) with Ti(NMe2)4 affords bis(dimethylamido)titanium complex [(η5-C5H4)CH2(2-C4H3N)]Ti(NMe2)2 (3) via amine elimination. A cyclopentadiene ligand with two pendant pyrrolyl arms, a mixture of 1,3- and 1,4-{CH2(2-C4H3NH)}2C5H4 (4), undergoes an analogous reaction with Ti(NMe2)4 to give [1,3-{CH2(2-C4H3N)}2(η5-C5H3)]Ti(NMe2) (5). Molecular structures of 3 and 5 have been determined by single crystal X-ray diffraction studies. 相似文献
37.
Ha-Yoon Nah Vinayak G. Parale Kyu-Yeon Lee Haryeong Choi Taehee Kim Chang-Hyun Lim Ji-Yeon Seo Yang Seo Ku Jae-Woo Park Hyung-Ho Park 《Journal of Sol-Gel Science and Technology》2018,87(2):319-330
Trimethylethoxysilane (TMES) has been recognized as a good co-precursor to increase the degree of hydrophobicity during the synthesis of a silica aerogel because of its methyl groups. Therefore, some physical properties of silica aerogels, including the contact angle and porosity, were investigated using TMES as a co-precursor at different molar ratios with the main precursor such as tetramethoxysilane (TMOS) or tetraethoxysilane (TEOS). In contrast to TMES, most silylating agents such as hexamethyldisilazane (HMDZ) and trimethylchlorosilane (TMCS) have been used for surface modification because of their ability to enhance the hydrophobicity of the aerogel surface. This work examines the silylation effect, which includes increasing hydrophobicity by TMES to determine the possibility of using it as an alternative silylating agent during ambient pressure drying in the synthesis of sodium silicate-based silica aerogel. In addition, the physical properties of sodium silicate-based silica aerogels with silylation under different TMES/TMCS volume ratio are investigated. The physical properties of sodium silicate-based aerogels can be changed by the TMES/TMCS volume ratio during the surface modification step. Aerogels with a high specific surface area (458?m2/g), pore volume (3.215?cm3/g), porosity (92.7%), and contact angle (131.8°) can be obtained TMES/TMCS volume ratio of 40/60. 相似文献
38.
Kie Yong Cho Hyun-Ji Kim Xuan Huy Do Jin Young Seo Jae-Woo Choi Sang-Hyup Lee Ho Gyu Yoon Seung Sang Hwang Kyung-Youl Baek 《Research on Chemical Intermediates》2018,44(8):4663-4684
Two series of water-soluble metalloporphyrin-cored amphiphilic star block copolymers were synthesized by controlled radical polymerizations such as atom transfer radical polymerization (ATRP) and reversible addition fragmentation chain transfer (RAFT), which gave eight amphiphilic block copolymer arm chains consisting of poly(n-butyl acrylate-b-poly(ethylene glycol) methyl ether methacylate) (PnBA-b-PEGMEMA, Mn,GPC = 78,000, Mw/Mn = 1.2, 70 wt% of PPEGMEMA) and poly(styrene-b-2-dimethylamino ethyl acrylate) (PS-b-PDMAEA, Mn,GPC = 83,000, Mw/Mn = 1.2, 67 wt% of PDMAEA), yielding porphyrin(Pd)-(PnBA-b-PPEGMEMA)8 and porphyrin(Pd)-(PS-b-PDMAEA)8, respectively. Obtained metalloporphyrin polymer photocatalysts were homogeneously solubilized in water to apply to the removal of chlorophenols in water, and was distinguished from conventional water-insoluble small molecular metalloporphyrin photocatalysts. Notably, we found that the water-soluble star block copolymers with hydrophobic–hydrophilic core–shell structures more effectively decomposed the chlorophenol, 2,4,6-trichlorophenol (2,4,6-TCP), in water under visible light irradiation (k = 1.39 h?1, t1/2 = 0.5 h) in comparison to the corresponding water-soluble star homopolymer, because the hydrophobic core near the metalloporphyrin effectively captured and decomposed the hydrophobic chlorophenols in water. 相似文献
39.
Zhenghua Li Chengbin Li Su Bin Park Gyoung Hee Hong Jin Seo Park Byung Jin Song Chul Wee Lee Ji Man Kim 《Research on Chemical Intermediates》2018,44(6):3687-3695
Oxidative desulfurization (ODS) of organic compounds containing sulfur element from a model oil was performed using tungsten oxide catalysts supported on mesoporous silica with cubic Ia3d mesostructure, well-defined mesopores (7.2 nm), high surface area (719 m2/g), and three-dimensional pore network (WO x /KIT-6). The prepared WO x /KIT-6 catalysts (5–20 wt% WO x ) were characterized by X-ray diffraction analysis, N2 sorption measurements, electron microscopy, H2-temperature programmed reduction, Raman spectroscopy, and thermogravimetric analysis. Among the mesoporous catalysts, 10 wt% WO x /KIT-6 exhibited the best catalytic performance. Sulfur-containing organic compounds, such as dibenzothiophene, 4,6-dimethyldibenzothiophene, and benzothiophene, were completely (100 %) removed from the model oil over 10 wt% WO x /KIT-6 catalyst in 2 h. In addition, the catalyst could be reused several times with only slight decrease in catalytic activity. 相似文献
40.
Érica Aparecida de Oliveira Bluma Linkowski Faintuch Daniele Seo Angélica Bueno Barbezan Ana Funari Roselaine Campos Targino Ana Maria Moro 《Applied biochemistry and biotechnology》2018,185(4):863-874
Early and accurate detection of primary or metastatic tumors is of great value in staging, treatment management, and prognosis. Tumor angiogenesis plays an essential role in the growth, invasion, and metastatic spread of solid cancers, and so, is a promising approach for tumor imaging. The GX1 (CGNSNPKSC) peptide was identified by phage display library and has been investigated as a marker for human cancers. This study aims to evaluate the 99mTc-HYNIC-PEG4-c (GX1) as a biomarker for tumor imaging. Our results showed that GX1 specifically binds to tumor cells in vitro. SKMEL28 and MDA-MB231 cells achieved total binding peak at 60 min of incubation. For B16F10 and MKN45 cells, the total and specific binding were similar during all time points, while A549 cell line showed rapid cellular total uptake of the tracer at 30 min of incubation. Biodistribution showed low non-specific uptakes and rapid renal excretion. Melanoma tumors showed enhanced GX1 uptake in animal model at 60 min, and it was significantly blocked by cold peptide. The radiotracer showed tumor specificity, especially in melanomas that are highly vascularized tumors. In this sense, it should be considered in future studies, aiming to evaluate degree of angiogenesis, progression, and invasion of tumors. 相似文献