The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform

Masao Suzuki - One of the best experts on this subject based on the ideXlab platform.

Miquel Àngel Cuevas-diarte - One of the best experts on this subject based on the ideXlab platform.

  • Fatty Acids polymorphism and solid-state miscibility: Pentadecanoic Acid–hexadecanoic Acid binary system
    Journal of Alloys and Compounds, 2008
    Co-Authors: Gabin Gbabode, Philippe Négrier, Denise Mondieig, Evelyn Moreno, Teresa Calvet, Miquel Àngel Cuevas-diarte
    Abstract:

    The Pentadecanoic Acid–hexadecanoic Acid (C15H29OOH–C16H31OOH) binary system is dealt with in this article. The polymorphism of 20 mixed materials has been investigated combining calorimetric measurements, isothermal and versus temperature X-ray powder diffraction and also FTIR spectroscopy. In particular, the cell parameters of the stable forms, temperatures and heats of phase changes for the two constituents and a proposal of phase diagram are given in this article. Three solid forms are created by mixing in addition with the four solid forms of the pure components. All these solid forms are stabilized on narrow domains of composition, implying a reduced solid-state miscibility of the Pentadecanoic and hexadecanoic Acids.

  • Polymorphism and solid-state miscibility in the Pentadecanoic Acid-heptadecanoic Acid binary system.
    Chemistry and Physics of Lipids, 2008
    Co-Authors: Gabin Gbabode, Philippe Négrier, Denise Mondieig, Evelyn Moreno, Teresa Calvet, Miquel Àngel Cuevas-diarte
    Abstract:

    The Pentadecanoic Acid-heptadecanoic Acid (C(15)H(29)OOH-C(17)H(33)OOH) binary system is dealt with in this article. Combined thermal analysis and X-ray powder diffraction experiments are performed to characterize the polymorphism of the pure compounds and of their mixed samples. In particular, modern methods of crystal structure resolution from powder data (direct space methods) are applied in order to investigate and compare the molecular arrangement within the solid phases of the fatty Acids considered. A proposal of the binary phase diagram is given. It exhibits no less than eight distinct solid phases stabilized on relatively narrow domains of composition which shows the reduced miscibility of the constituents. Finally, a structural model of one of the intermediate solid solutions is developed which well accounts for the mixing behaviour of the two fatty Acids and permits to propose an explanation about their low solid-state miscibility.

Gabin Gbabode - One of the best experts on this subject based on the ideXlab platform.

  • fatty Acids polymorphism and solid state miscibility Pentadecanoic Acid hexadecanoic Acid binary system
    Journal of Alloys and Compounds, 2009
    Co-Authors: Gabin Gbabode, Philippe Négrier, Denise Mondieig, Evelyn Moreno, Teresa Calvet, Miquel Angel Cuevasdiarte
    Abstract:

    The Pentadecanoic Acid–hexadecanoic Acid (C15H29OOH–C16H31OOH) binary system is dealt with in this article. The polymorphism of 20 mixed materials has been investigated combining calorimetric measurements, isothermal and versus temperature X-ray powder diffraction and also FTIR spectroscopy. In particular, the cell parameters of the stable forms, temperatures and heats of phase changes for the two constituents and a proposal of phase diagram are given in this article. Three solid forms are created by mixing in addition with the four solid forms of the pure components. All these solid forms are stabilized on narrow domains of composition, implying a reduced solid-state miscibility of the Pentadecanoic and hexadecanoic Acids.

  • Fatty Acids polymorphism and solid-state miscibility: Pentadecanoic Acid–hexadecanoic Acid binary system
    Journal of Alloys and Compounds, 2008
    Co-Authors: Gabin Gbabode, Philippe Négrier, Denise Mondieig, Evelyn Moreno, Teresa Calvet, Miquel Àngel Cuevas-diarte
    Abstract:

    The Pentadecanoic Acid–hexadecanoic Acid (C15H29OOH–C16H31OOH) binary system is dealt with in this article. The polymorphism of 20 mixed materials has been investigated combining calorimetric measurements, isothermal and versus temperature X-ray powder diffraction and also FTIR spectroscopy. In particular, the cell parameters of the stable forms, temperatures and heats of phase changes for the two constituents and a proposal of phase diagram are given in this article. Three solid forms are created by mixing in addition with the four solid forms of the pure components. All these solid forms are stabilized on narrow domains of composition, implying a reduced solid-state miscibility of the Pentadecanoic and hexadecanoic Acids.

  • Polymorphism and solid-state miscibility in the Pentadecanoic Acid-heptadecanoic Acid binary system.
    Chemistry and Physics of Lipids, 2008
    Co-Authors: Gabin Gbabode, Philippe Négrier, Denise Mondieig, Evelyn Moreno, Teresa Calvet, Miquel Àngel Cuevas-diarte
    Abstract:

    The Pentadecanoic Acid-heptadecanoic Acid (C(15)H(29)OOH-C(17)H(33)OOH) binary system is dealt with in this article. Combined thermal analysis and X-ray powder diffraction experiments are performed to characterize the polymorphism of the pure compounds and of their mixed samples. In particular, modern methods of crystal structure resolution from powder data (direct space methods) are applied in order to investigate and compare the molecular arrangement within the solid phases of the fatty Acids considered. A proposal of the binary phase diagram is given. It exhibits no less than eight distinct solid phases stabilized on relatively narrow domains of composition which shows the reduced miscibility of the constituents. Finally, a structural model of one of the intermediate solid solutions is developed which well accounts for the mixing behaviour of the two fatty Acids and permits to propose an explanation about their low solid-state miscibility.

Fumitoshi Kaneko - One of the best experts on this subject based on the ideXlab platform.

Brian A Pethica - One of the best experts on this subject based on the ideXlab platform.

  • intermolecular forces in lipid monolayers two dimensional virial coefficients for Pentadecanoic Acid from micromanometry on spread monolayers at the air water interface
    Physical Chemistry Chemical Physics, 2009
    Co-Authors: Norman R Pallas, Brian A Pethica
    Abstract:

    The lateral intermolecular forces between surfactant or lipid molecules in monolayers at interfaces are fundamental to understanding the phenomena of surface activity and the interactions of lipids in two-dimensional structures such as smectic phases and biomembranes. The classical approach to these forces is via the two-dimensional virial coefficients, which requires precise micromanometry on monolayer isotherms in the dilute gaseous region. Low pressure isotherms out to high surface areas in the two-dimensional gas range have been measured at 15, 25 and 30 °C for insoluble monolayers of n-Pentadecanoic Acid spread at the interface between water-vapour saturated air and a dilute aqueous solution of HCl. The data allow estimates of virial coefficients up to the third term. The second virial coefficients are compared with those predicted from a statistical mechanical model for monolayers of n-alkylcarboxylic Acids treated as side-by-side parallel chains extended at the surface with the carboxyl head groups shielded in the water phase. The two sets coincide at ∼26 °C, but the experimental estimates show a much larger dependence on temperature than the model predicts. Chain conformation effects, head group interactions and surface field polarization are discussed as possible temperature-dependent contributions to the lateral potentials of mean force.

  • Intermolecular forces in lipid monolayers. Two-dimensional virial coefficients for Pentadecanoic Acid from micromanometry on spread monolayers at the air/water interface
    Physical chemistry chemical physics : PCCP, 2009
    Co-Authors: Norman R Pallas, Brian A Pethica
    Abstract:

    The lateral intermolecular forces between surfactant or lipid molecules in monolayers at interfaces are fundamental to understanding the phenomena of surface activity and the interactions of lipids in two-dimensional structures such as smectic phases and biomembranes. The classical approach to these forces is via the two-dimensional virial coefficients, which requires precise micromanometry on monolayer isotherms in the dilute gaseous region. Low pressure isotherms out to high surface areas in the two-dimensional gas range have been measured at 15, 25 and 30 degrees C for insoluble monolayers of n-Pentadecanoic Acid spread at the interface between water-vapour saturated air and a dilute aqueous solution of HCl. The data allow estimates of virial coefficients up to the third term. The second virial coefficients are compared with those predicted from a statistical mechanical model for monolayers of n-alkylcarboxylic Acids treated as side-by-side parallel chains extended at the surface with the carboxyl head groups shielded in the water phase. The two sets coincide at approximately 26 degrees C, but the experimental estimates show a much larger dependence on temperature than the model predicts. Chain conformation effects, head group interactions and surface field polarization are discussed as possible temperature-dependent contributions to the lateral potentials of mean force.