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Takanori Takiue - One of the best experts on this subject based on the ideXlab platform.
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solid film formation at the tetradecane aqueous hexadecyltrimethylammonium bromide solution interface studied by interfacial tensiometry and x ray reflectometry
Journal of Physical Chemistry B, 2019Co-Authors: Haruna Hayase, Yosuke Imai, Toshiaki Ina, Kiyofumi Nitta, Hajime Tanida, Tomoya Uruga, Takanori TakiueAbstract:The effect of oil on condensed film formation in the adsorbed film of hexadecyltrimethylammonium bromide (C16TAB) at the tetradecane (C14)/water (W) interface was examined by interfacial tension and X-ray reflectivity measurements. The interfacial tension vs temperature curves have break point due to the expanded?condensed phase transition of the adsorbed film. The partial Molar Entropy of C16TAB at the interface changes discontinuously, whereas the interfacial density changes almost continuously at the phase transition point. The electron density profile normal to the interface manifested that the condensed film is regarded as a two-dimensional (2D) solid rotator phase in which C16TAB and C14 molecules are densely packed with perpendicular orientation. Combining the interfacial tension and X-ray reflectivity data, the mixing ratio of C16TAB to C14 in the solid film was determined to be 2:3 and thus the film is enriched in oil molecules than surfactant ones. Furthermore, the partial Molar Entropy change of C14 associated with solid film formation was found to be largely negative and very close to that of surface freezing of liquid alkane, manifesting that C14 molecules are well ordered to form a 2D solid film by mixing with C16TAB molecules at the interface. The solid film formation of the present system is driven by effective vdW interactions between adsorbed C16TAB and intercalated C14 molecules. The morphology of the condensed domain observed during phase transition suggested that the contact energy is more predominant than the dipole repulsion at the domain boundary, which promotes coalescence of small domains into large ones during phase transition.
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adsorbed film of n tetradecylphosphocholine at the tetradecane water interface studied by interfacial tensiometry and x ray reflection
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015Co-Authors: Shinya Hiraki, Toshiaki Ina, Kiyofumi Nitta, Hajime Tanida, Tomoya Uruga, Hiroki Matsubara, Makoto Aratono, T Goto, Takanori TakiueAbstract:Abstract The adsorbed film of n-tetradecylphosphocholine (C14PC) at the tetradecane (C14)/aqueous solution (W) interface was studied by interfacial tensiometry and X-ray reflection (XR). The interfacial tension γ was measured as a function of molality m C 14 PC and temperature T under atmospheric pressure. The interfacial density of C14PC Γ C 14 PC H increases with increasing m C 14 PC and converges into 3 μmol m−2 (first saturation) at m C 14 PC ≈ 0.08 mmol kg − 1 and into 4.2 μmol m−2 (second saturation) at the critical micelle concentration (CMC). The electron density profile determined by XR indicated that C14PC molecules form monolayer with relatively loose packing at the first saturation. In the second saturation, on the other hand, the molecules form bilayer in which charge separated phosphocholine groups take upside-down arrangement to interact attractively between neighbors. The positive Entropy changes associated with adsorption both from monomeric and from micellar states result from that the contribution of dehydration around C14PC molecules, especially around PC groups, by the adsorption from aqueous solution overcomes that of a comparatively ordered molecular orientation at the interface. By comparing the results at the C14/W interface with those at the Air (A)/W one, it was shown that in the monolayer and bilayer states, hydrophobic chains of C14PC molecules are more ordered at the C14/W than at the A/W interface because of attractive interaction between C14PC and C14 molecules. This leads to smaller value of the partial Molar Entropy and energy changes associated with the adsorption at the C14/W than at the A/W interface. Furthermore the Entropy of micelle formation changes from positive to negative with increasing T, suggesting that the Entropy gain due to the dehydration exceeds the Entropy loss by the aggregation at low temperatures, while the gain is less than the loss at high temperature.
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molecular orientation and multilayer formation in the adsorbed film of 1h 1h 10h 10h perfluorodecane 1 10 diol at the hexane water interface temperature effect on the adsorption of fluoroalkane diol
Journal of Physical Chemistry C, 2008Co-Authors: Takanori Takiue, Tsubasa Fukuda, Daiki Murakami, Hideaki Inomata, Hiroyasu Sakamoto, Hiroki Matsubara, Makoto AratonoAbstract:The adsorption of lH,lH,10H,10H-perfluorodecane-1,10-diol (FC 10 diol) at the hexane/water interface was investigated by the measurement of temperature dependence of interfacial tension and the thermodynamic data analysis in order to know the effect of two hydroxyl groups at both ends of the hydrophobic chain and the rigidity of the hydrophobic chain on the adsorption of fluorocarbon alcohol at the interface. The curves of interfacial tension versus temperature and concentration show break points corresponding to the phase transitions in the adsorbed FC 10 diol film. The interfacial pressure versus mean area per adsorbed molecule curve shows three kinds of states connected by two discontinuous changes. The area value after the first phase transition is very close to the calculated cross-sectional area of the FC 10 diol molecule along its major axis, and thus the FC 10 diol molecules form a condensed monolayer with molecular orientation parallel to the interface. Another noticeable point is that the value after the second phase transition point decreases furthermore to 0.12 nm 2 , which is much smaller than the cross-sectional area of the fluorocarbon chain, 0.28 nm 2 , with increasing interfacial pressure. This suggests that FC 10 diol molecules pile spontaneously and successively form a multilayer above the second phase transition. Furthermore, the partial Molar Entropy and energy change of adsorption in the expanded and condensed states were evaluated and compared to those of 1H,1H,2H,-2H-perfluorodecanol (TFC 10 OH), which orients almost perpendicular to the interface. In addition to the contact of two hydroxyl groups with hexane in the bulk solution, the results are explained by the dependence of partial Molar Entropy and energy at the interface on the following factors resulting from the parallel orientation of FC 10 diol at the interface; (a) hydrogen bonding of two hydroxyl groups with water molecules, (b) hydrogen bonding between two hydroxyl groups facing each other, and (c) the fluorocarbon chain-water contact. The adsorbed FC 10 diol film is stabilized by factors a and b, which overwhelm the energetic disadvantage caused by factor c. Furthermore, the Entropy change of adsorption As in the multilayer is compared to the Δs cal calculated on the assumption that the condensed monolayer piles to form the multilayer. It was suggested that FC 10 diol molecules are not so densely packed in the multilayer compared to the first condensed monolayer and therefore the multilayer is not simply formed by the piling of condensed monolayers.
Z C Tan - One of the best experts on this subject based on the ideXlab platform.
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Molar heat capacities and standard Molar enthalpy of formation of 2 amino 5 methylpyridine
Journal of Thermal Analysis and Calorimetry, 2009Co-Authors: J N Zhang, Bo Tong, Qing Fen Meng, Z C Tan, Quanqi Shi, Shaoxu WangAbstract:The heat capacities (Cp,m) of 2-amino-5-methylpyridine (AMP) were measured by a precision automated adiabatic calorimeter over the temperature range from 80 to 398 K. A solid-liquid phase transition was found in the range from 336 to 351 K with the peak heat capacity at 350.426 K. The melting temperature (Tm), the Molar enthalpy (ΔfusHm0), and the Molar Entropy (ΔfusSm0) of fusion were determined to be 350.431±0.018 K, 18.108 kJ mol−1 and 51.676 J K−1 mol−1, respectively. The mole fraction purity of the sample used was determined to be 0.99734 through the Van’t Hoff equation. The thermodynamic functions (HT-H298.15 and ST-S298.15) were calculated. The Molar energy of combustion and the standard Molar enthalpy of combustion were determined, ΔUc(C6H8N2,cr)= −3500.15±1.51 kJ mol−1 and ΔcHm0 (C6H8N2,cr)= −3502.64±1.51 kJ mol−1, by means of a precision oxygen-bomb combustion calorimeter at T=298.15 K. The standard Molar enthalpy of formation of the crystalline compound was derived, ΔrHm0 (C6H8N2,cr)= −1.74±0.57 kJ mol−1.
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low temperature heat capacity and standard Molar enthalpy of formation of potassium l threonate hydrate k c4h7o5 center dot h2o
2006Co-Authors: Qing Wei, Z C Tan, S P Chen, S L Gao, Q Z ShiAbstract:The solid potassium L-threonate hydrate, K(C4H7O5)(H2O)-H-., was synthesized by the reaction of L-threonic acid with aqueous potassium hydrogen carbonate and characterized by means of chemical and elemental analyses, IR and TG-DTG. Low-temperature heat capacity of K(C4H7O5)(H2O)-H-. has been precisely measured with a small sample precise automated adiabatic calorimeter over the temperature range from 78 to 395 K. An obvious process of the dehydration occurred in the temperature region of 364-382 K. The peak temperature of the dehydration of the compound has been observed to be (380.524 +/- 0.093) K by means of the heat capacity measurements. The Molar enthalpy, Delta(d)H(m), and Molar Entropy, Delta(d)S(m), of the dehydration of K(C4H7O5)(H2O)-H-. were calculated to be (19.655 +/- 0.012) kJ/mol and (51.618 +/- 0.051) J/(K-mol) by the analysis of the heat-capacity curve. The experimental Molar heat capacities of the solid from 78 to 362 K and from 382 to 395 K have been respectively fitted to two polynomial equations of heat capacities against the reduced temperatures by least square method. The constant-volume energy of combustion of the compound, Delta(c)U(m), has been determined to be (-1749.71 +/- 0.91) kJ(.)mol(-1) by an RBC-II precision rotary-bomb combustion calorimeter at 298.15 K. The standard Molar enthalpy of formation of the compound, Delta(f)H(m)(theta) has been calculated to be (- 1292.56 +/- 1.06) kJ(.)mol(-1) from the combination of the standard Molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities.
Brian F Woodfield - One of the best experts on this subject based on the ideXlab platform.
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heat capacity studies of the iron oxyhydroxides akaganeite β feooh and lepidocrocite γ feooh
The Journal of Chemical Thermodynamics, 2011Co-Authors: Claine L Snow, Brian F Woodfield, Juliana Boeriogoates, Stacey J Smith, B E Lang, Alexandra NavrotskyAbstract:Abstract The iron oxides and iron oxyhydroxides exist as several different polymorphs, and a thermodynamic understanding of these polymorphs can provide us with an understanding of their relative stability and chemical reactivity. This study provides heat capacity measurements for lepidocrocite (γ-FeOOH) over the temperature range (0.8 to 38) K and akaganeite (β-FeOOH) over the range (0.7 to 302) K. Fits of the heat capacity of the two samples below T = 15 K showed similar behavior to previously published fits of goethite (α-FeOOH), which required a linear term and an anisotropic gap parameter to model accurately the antiferromagnetic spin–wave contributions. The akaganeite measurements were compared to previously reported measurements all of which showed significant disagreement. It is believed that the measurements reported here are the most reliable. Also, the presence of adsorbed water contributes significantly to the heat capacity of akaganeite, and the standard Molar Entropy at T = 298.15 K of the hydrated form was calculated to be (81.8 ± 2) J · mol−1 · K−1.
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heat capacity third law Entropy and low temperature physical behavior of bulk hematite α fe2o3
The Journal of Chemical Thermodynamics, 2010Co-Authors: Claine L Snow, Juliana Boeriogoates, Brian F WoodfieldAbstract:Abstract The constant pressure heat capacity of a bulk hematite powder was measured using a Quantum Design physical properties measurement system (PPMS). The results of two series showed good precision and agreed well with measurements reported by Westrum and Gronvold. The standard Molar Entropy at T = 298.15 K was calculated to be (87.32 ± 2) J · mol −1 · K −1 for Series 1 and (87.27 ± 2) J · mol −1 · K −1 for Series 2, which are in good agreement with the value of (87.40 ± 0.2) J · mol −1 · K −1 (originally 20.889 cal · deg −1 · mole −1 ) calculated by Westrum and Gronvold. No anomaly was observed for the Morin transition, and theoretical fits below T = 15 K required a ferromagnetic T 3/2 term.
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heat capacities third law entropies and thermodynamic functions of the negative thermal expansion material zn2geo4 from t 0 to 400 k
The Journal of Chemical Thermodynamics, 2004Co-Authors: Rebecca Stevens, Brian F Woodfield, Juliana Boeriogoates, M K CrawfordAbstract:Abstract The Molar heat capacity of Zn2GeO4, a material which exhibits negative thermal expansion below ambient temperatures, has been measured in the temperature range 0.5⩽(T/K)⩽400. At T=298.15 K, the standard Molar heat capacity is (131.86 ± 0.26) J · K−1 · mol−1. Thermodynamic functions have been generated from smoothed fits of the experimental results. The standard Molar Entropy at T=298.15 K is (145.12 ± 0.29) J · K−1 · mol−1. The existence of low-energy modes is supported by the excess heat capacity in Zn2GeO4 compared to the sums of the constituent binary oxides.
Juliana Boeriogoates - One of the best experts on this subject based on the ideXlab platform.
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heat capacity studies of the iron oxyhydroxides akaganeite β feooh and lepidocrocite γ feooh
The Journal of Chemical Thermodynamics, 2011Co-Authors: Claine L Snow, Brian F Woodfield, Juliana Boeriogoates, Stacey J Smith, B E Lang, Alexandra NavrotskyAbstract:Abstract The iron oxides and iron oxyhydroxides exist as several different polymorphs, and a thermodynamic understanding of these polymorphs can provide us with an understanding of their relative stability and chemical reactivity. This study provides heat capacity measurements for lepidocrocite (γ-FeOOH) over the temperature range (0.8 to 38) K and akaganeite (β-FeOOH) over the range (0.7 to 302) K. Fits of the heat capacity of the two samples below T = 15 K showed similar behavior to previously published fits of goethite (α-FeOOH), which required a linear term and an anisotropic gap parameter to model accurately the antiferromagnetic spin–wave contributions. The akaganeite measurements were compared to previously reported measurements all of which showed significant disagreement. It is believed that the measurements reported here are the most reliable. Also, the presence of adsorbed water contributes significantly to the heat capacity of akaganeite, and the standard Molar Entropy at T = 298.15 K of the hydrated form was calculated to be (81.8 ± 2) J · mol−1 · K−1.
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heat capacity third law Entropy and low temperature physical behavior of bulk hematite α fe2o3
The Journal of Chemical Thermodynamics, 2010Co-Authors: Claine L Snow, Juliana Boeriogoates, Brian F WoodfieldAbstract:Abstract The constant pressure heat capacity of a bulk hematite powder was measured using a Quantum Design physical properties measurement system (PPMS). The results of two series showed good precision and agreed well with measurements reported by Westrum and Gronvold. The standard Molar Entropy at T = 298.15 K was calculated to be (87.32 ± 2) J · mol −1 · K −1 for Series 1 and (87.27 ± 2) J · mol −1 · K −1 for Series 2, which are in good agreement with the value of (87.40 ± 0.2) J · mol −1 · K −1 (originally 20.889 cal · deg −1 · mole −1 ) calculated by Westrum and Gronvold. No anomaly was observed for the Morin transition, and theoretical fits below T = 15 K required a ferromagnetic T 3/2 term.
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heat capacities third law entropies and thermodynamic functions of the negative thermal expansion material zn2geo4 from t 0 to 400 k
The Journal of Chemical Thermodynamics, 2004Co-Authors: Rebecca Stevens, Brian F Woodfield, Juliana Boeriogoates, M K CrawfordAbstract:Abstract The Molar heat capacity of Zn2GeO4, a material which exhibits negative thermal expansion below ambient temperatures, has been measured in the temperature range 0.5⩽(T/K)⩽400. At T=298.15 K, the standard Molar heat capacity is (131.86 ± 0.26) J · K−1 · mol−1. Thermodynamic functions have been generated from smoothed fits of the experimental results. The standard Molar Entropy at T=298.15 K is (145.12 ± 0.29) J · K−1 · mol−1. The existence of low-energy modes is supported by the excess heat capacity in Zn2GeO4 compared to the sums of the constituent binary oxides.
Alan L. Rockwood - One of the best experts on this subject based on the ideXlab platform.
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Partial Molar Entropy and Partial Molar Heat Capacity of Electrons in Metals and Superconductors
Journal of Modern Physics, 2016Co-Authors: Alan L. RockwoodAbstract:There are at least two valid approaches to the thermodynamics of electrons in metals. One takes a microscopic view, based on models of electrons in metals and superconductor and uses statistical mechanics to calculate the total thermodynamic functions for the model-based system. Another uses partial Molar quantities, which is a rigorous thermodynamic method to analyze systems with components that can cross phase boundaries and is particularly useful when applied to a system composed of interacting components. Partial Molar quantities have not been widely used in the field of solid state physics. The present paper will explore the application of partial Molar electronic Entropy and partial Molar electronic heat capacity to electrons in metals and superconductors. This provides information that is complementary information from other approaches to the thermodynamics of electrons in metals and superconductors and can provide additional insight into the properties of those materials. Furthermore, the application of partial Molar quantities to electrons in metals and superconductors has direct relevance to long-standing problems in other fields, such as the thermodynamics of ions in solution and the thermodynamics of biological energy transformations. A unifying principle between reversible and irreversible thermodynamics is also discussed, including how this relates to the completeness of thermodynamic theory.
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partial Molar Entropy of electrons in a jellium model implications for thermodynamics of ions in solution and electrons in metals
Electrochimica Acta, 2013Co-Authors: Alan L. RockwoodAbstract:Abstract A universal relationship between the partial Molar Entropy of electrons in a conductor and the absolute thermoelectric power of the conductor was previously established using macroscopic thermodynamics. This relationship may depend on temperature but not on the type of material. Building on this, a recent comment published in this journal, as well as some earlier work, has argued that the partial Molar Entropy of electrons in a conductor is essentially equivalent to the absolute thermoelectric power of the metal. The argument was based on the thermodynamic and transport properties of a free electron Fermi gas. To further validate the relationship the present paper extends this approach to a jellium model of electronic structure. If the proposed equivalence between partial Molar Entropy and absolute thermoelectric power is valid it opens the way for an experimental thermodynamic method to measure quantities that have previously been considered un-measurable, such as partial Molar entropies of ions in solution and electric fields in homogeneous conductors placed in a temperature gradient. It also relates to questions about the completeness of current thermodynamic theory and the possibility of a new principle or law of thermodynamics.