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Yoshifumi Koide - One of the best experts on this subject based on the ideXlab platform.
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Physicochemical properties of resorcinol-type calix[4]arenes phosphoric esters having four Alkyl Side Chains in aqueous solution
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2001Co-Authors: Kunio Esumi, Yoshifumi Koide, Kei Shoji, Kanjiro Torigoe, Hideto ShosenjiAbstract:The physicochemical properties of phosphate esters of resorcinol-type of calix[4]arenes([4]Ar5P-Rn; Side Chain length n=6, 8, and 12) in aqueous solutions have been characterized by several techniques including surface tension and NMR. It is found that the critical micelle concentrations (cmcs) of [4]Ar5P-Rn are insensitive against the Alkyl Side Chain length, whereas the polarity of aggregates remarkably depends on the Alkyl Side Chain length. From static light scattering and NMR measurements it is suggested that the shapes of aggregates of [4]Ar5P-Rn are not globular and the Alkyl Side Chains of [4]Ar5P-Rn gather loosely in the aggregates. The mixed properties of [4[Ar5P-R12 and hexaethyleneglycol dodecylether have also been investigated. The mixed cmcs are conSiderably greater than those of the respective surfactant cmcs and the interaction parameter calculated using a modified regular solution theory is +2.7. These results indicate that the repulsive interactions occur in the mixed micelles.
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Aqueous properties of resorcinol-type calix[4]arenes bearing four Alkyl Side Chains
Langmuir, 1996Co-Authors: Kayo Sugiyama, Kunio Esumi, Yoshifumi KoideAbstract:The resorcinol-type calix[4]arenes bearing Alkyl Side Chains ([4]Ar-Rn, n = 4, 6, 8) have been prepared, and their aqueous properties at pH 13 have been studied by measuring the surface tension, NMR, and solubilization behavior of benzene. It is found from the surface tension measurements that the formation of micelles is promoted and the surface tension value at the critical micelle concentration cmc is decreased with increasing Alkyl Side Chain length. The results of 2D-NMR and relaxation measurements suggest that the interaction of Alkyl Side Chains in the micelles becomes weak, but the interaction between the resorcinol ring and the inner Alkyl Side group is increased with increasing Alkyl Side Chain length. In the solubilization of benzene, benzene molecules are mainly incorporated in the resorcinol ring part of [4]Ar-R4, whereas they are solubilized in the Alkyl Side Chains of [4]Ar-R6.
João A. P. Coutinho - One of the best experts on this subject based on the ideXlab platform.
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Glycerol Ethers as Hydrotropes and their use to Enhance the Solubility of Phenolic Acids in Water
ACS Sustainable Chemistry & Engineering, 2020Co-Authors: Bruna P. Soares, Dinis O. Abranches, Tânia E. Sintra, Alejandro Leal-duaso, José I. García, Elísabet Pires, Seishi Shimizu, Simão P. Pinho, João A. P. CoutinhoAbstract:The use of glycerol ethers (with Alkyl Side Chain ranging from one to six methyl groups) as hydrotropes to enhance the solubility of gallic and syringic acids in water was here studied. These compo...
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comprehensive study on the impact of the cation Alkyl Side Chain length on the solubility of water in ionic liquids
Journal of Molecular Liquids, 2015Co-Authors: Kiki A Kurnia, Mara G. Freire, Luís M. N. B. F. Santos, Catarina M S S Neves, João A. P. CoutinhoAbstract:A comprehensive study on the phase behaviour of two sets of ionic liquids (ILs) and their interactions with water is here presented through combining experimental and theoretical approaches. The impact of the Alkyl Side Chain length and the cation symmetry on the water solubility in the asymmetric [C N-1C1im][NTf2] and symmetric [C N-1C N-1im][NTf2] series of ILs (N up to 22), from 288.15 K to 318.15 K and at atmospheric pressure, was studied. The experimental data reveal that the solubility of water in ILs with an asymmetric cation is higher than in those with the symmetric isomer. Several trend shifts on the water solubility as a function of the Alkyl Side Chain length were identified, namely at [C6C1im][NTf2] for asymmetric ILs and at [C4C4im][NTf2] and [C7C7im][NTf2] for the symmetric ILs. To complement the experimental data and to further investigate the molecular-level mechanisms behind the dissolution process, Density Functional Theory calculations, using the Conductor-like Screening Model for Real Solvents (COSMO-RS) and the Electrostatic potential-derived CHelpG, were performed. The COSMO-RS model is able to qualitatively predict water solubility as function of temperature and Alkyl Chain lengths of both symmetric and asymmetric cations. Furthermore, the model is also capable to predict the somewhat higher water solubility in the asymmetric cation, as well as the trend shift as function of Alkyl Chain lengths experimentally observed. Both COSMO-RS and the electrostatic potential-derived CHelpG show that the interactions of water and the IL cation take place on the IL polar region, namely on the aromatic head and adjacent methylene groups what explains the differences in water solubility observed for cations with different Chain lengths. Furthermore, the CHelpG calculations for the isolated cations in the gas phase indicates that the trend shift of water solubility as function of Alkyl Chain lengths and the difference of water solubility in symmetric may also result from the partial positive charge distribution/contribution of the cation.
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Cation Alkyl Side Chain Length and Symmetry Effects on the Surface Tension of Ionic Liquids
Langmuir : the ACS journal of surfaces and colloids, 2014Co-Authors: Hugo F. D. Almeida, Mara G. Freire, Ana Fernandes, José A. Lopes-da-silva, Pedro Morgado, Karina Shimizu, Eduardo J. M. Filipe, José N. Canongia Lopes, Luís M. N. B. F. Santos, João A. P. CoutinhoAbstract:Aiming at providing a comprehensive study of the influence of the cation symmetry and Alkyl Side Chain length on the surface tension and surface organization of ionic liquids (ILs), this work addresses the experimental measurements of the surface tension of two extended series of ILs, namely R,R′-diAlkylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([CnCnim][NTf2]) and R-Alkyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([CnC1im][NTf2]), and their dependence with temperature (from 298 to 343 K). For both series of ILs the surface tension decreases with an increase in the cation Side Alkyl Chain length up to aliphatic Chains no longer than hexyl, here labeled as critical Alkyl Chain length (CACL). For ILs with aliphatic moieties longer than CACL the surface tension displays an almost constant value up to [C12C12im][NTf2] or [C16C1im][NTf2]. These constant values further converge to the surface tension of long Chain n-alkanes, indicating that, for sufficiently long Alkyl Side Chains, the surfa...
Kunio Esumi - One of the best experts on this subject based on the ideXlab platform.
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Physicochemical properties of resorcinol-type calix[4]arenes phosphoric esters having four Alkyl Side Chains in aqueous solution
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2001Co-Authors: Kunio Esumi, Yoshifumi Koide, Kei Shoji, Kanjiro Torigoe, Hideto ShosenjiAbstract:The physicochemical properties of phosphate esters of resorcinol-type of calix[4]arenes([4]Ar5P-Rn; Side Chain length n=6, 8, and 12) in aqueous solutions have been characterized by several techniques including surface tension and NMR. It is found that the critical micelle concentrations (cmcs) of [4]Ar5P-Rn are insensitive against the Alkyl Side Chain length, whereas the polarity of aggregates remarkably depends on the Alkyl Side Chain length. From static light scattering and NMR measurements it is suggested that the shapes of aggregates of [4]Ar5P-Rn are not globular and the Alkyl Side Chains of [4]Ar5P-Rn gather loosely in the aggregates. The mixed properties of [4[Ar5P-R12 and hexaethyleneglycol dodecylether have also been investigated. The mixed cmcs are conSiderably greater than those of the respective surfactant cmcs and the interaction parameter calculated using a modified regular solution theory is +2.7. These results indicate that the repulsive interactions occur in the mixed micelles.
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Aqueous properties of resorcinol-type calix[4]arenes bearing four Alkyl Side Chains
Langmuir, 1996Co-Authors: Kayo Sugiyama, Kunio Esumi, Yoshifumi KoideAbstract:The resorcinol-type calix[4]arenes bearing Alkyl Side Chains ([4]Ar-Rn, n = 4, 6, 8) have been prepared, and their aqueous properties at pH 13 have been studied by measuring the surface tension, NMR, and solubilization behavior of benzene. It is found from the surface tension measurements that the formation of micelles is promoted and the surface tension value at the critical micelle concentration cmc is decreased with increasing Alkyl Side Chain length. The results of 2D-NMR and relaxation measurements suggest that the interaction of Alkyl Side Chains in the micelles becomes weak, but the interaction between the resorcinol ring and the inner Alkyl Side group is increased with increasing Alkyl Side Chain length. In the solubilization of benzene, benzene molecules are mainly incorporated in the resorcinol ring part of [4]Ar-R4, whereas they are solubilized in the Alkyl Side Chains of [4]Ar-R6.
Ali Dhinojwala - One of the best experts on this subject based on the ideXlab platform.
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Partial Crystallinity in Alkyl Side Chain Polymers Dictates Surface Freezing
Physical review letters, 2008Co-Authors: Shishir Prasad, Zhang Jiang, Sunil K. Sinha, Ali DhinojwalaAbstract:We have studied the structure of a novel crystalline surface monolayer on top of a disordered melt of the same material [poly(n-Alkyl acrylate)s] using grazing incidence x-ray diffraction. The grazing incidence x-ray diffraction, surface tension, and bulk latent heat results show that Side Chains crystallize except the nine methylene units of the Alkyl Side Chains closest to the polymer backbone. The partial crystallinity along with a thicker surface layer, due to the additional length of the linker group, explains why the difference between the surface order-to-disorder transition temperature and bulk melting temperature increases with a decrease in the length of the Alkyl Side Chain.
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molecular structure of an Alkyl Side Chain polymer water interface origins of contact angle hysteresis
Langmuir, 2004Co-Authors: Hasnain Rangwalla, Alexander D Schwab, Betul Yurdumakan, Dalia G Yablon, Mohsen S Yeganeh, Ali DhinojwalaAbstract:A new and direct approach to verify surface heterogeneity as the microscopic origin of contact-angle hysteresis is demonstrated. IR−visible sum-frequency-generation spectroscopy (SFG) was used to selectively probe the molecules at the interface of an Alkyl-Side-Chain polymer [poly(vinyl n-octadecyl carbamate-co-vinyl acetate)] with water. The spectra indicate that in contact with water, the polymer surface is heterogeneous (having areas of differing surface energies). This evidence of surface heterogeneity supports the hysteresis observed in the advancing and receding contact angles of the polymer surface with water. The same measurements made for the chemically and structurally similar surface of an octadecyltrichlorosilane self-assembled monolayer indicates a homogeneous surface at the water interface. In this case, contact-angle hysteresis measurements implicate surface roughness as the cause of hysteresis. Atomic force microscopy measurements of roughness for these surfaces further support our conclus...
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Melting at Alkyl Side Chain comb polymer interfaces.
Physical review letters, 2002Co-Authors: Keshav S. Gautam, Ali DhinojwalaAbstract:Infrared visible sum frequency generation (SFG) spectroscopy has been used to study structure and melting transition temperatures of Alkyl-Side Chain-acrylate comb polymers at air and solid interfaces. At the air interface, the SFG spectra show methyl bands and two transitions are observed: the first, near the bulk melting temperature, ${T}_{m}$, and the second 10--20 \ifmmode^\circ\else\textdegree\fi{}C higher than ${T}_{m}$. The shorter the Alkyl Side Chain, the larger the difference between the two transition temperatures. In contrast, methylene bands are observed at sapphire interface with a single transition near ${T}_{m}$ (C18).
Hideto Shosenji - One of the best experts on this subject based on the ideXlab platform.
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Physicochemical properties of resorcinol-type calix[4]arenes phosphoric esters having four Alkyl Side Chains in aqueous solution
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2001Co-Authors: Kunio Esumi, Yoshifumi Koide, Kei Shoji, Kanjiro Torigoe, Hideto ShosenjiAbstract:The physicochemical properties of phosphate esters of resorcinol-type of calix[4]arenes([4]Ar5P-Rn; Side Chain length n=6, 8, and 12) in aqueous solutions have been characterized by several techniques including surface tension and NMR. It is found that the critical micelle concentrations (cmcs) of [4]Ar5P-Rn are insensitive against the Alkyl Side Chain length, whereas the polarity of aggregates remarkably depends on the Alkyl Side Chain length. From static light scattering and NMR measurements it is suggested that the shapes of aggregates of [4]Ar5P-Rn are not globular and the Alkyl Side Chains of [4]Ar5P-Rn gather loosely in the aggregates. The mixed properties of [4[Ar5P-R12 and hexaethyleneglycol dodecylether have also been investigated. The mixed cmcs are conSiderably greater than those of the respective surfactant cmcs and the interaction parameter calculated using a modified regular solution theory is +2.7. These results indicate that the repulsive interactions occur in the mixed micelles.
