The single components of association colloids are amphiphilic molecules, which are held together by van der Waals forces and/or hydrogen interactions. The thermodynamic parameters associated with the aggregation behaviour of amphiphiles depend on the chemical nature of the molecules as well as their environmental conditions (temperature, ionic strength, etc.). The systems studied and presented in this paper are association colloids, also known as micellar systems, which are formed of biological relevant detergents (e.g. bile salts, fatty acids). Information concerning the self-organisation (self-aggregation) of such micellar colloids can be easily obtained from isothermal titration calorimetry (ITC), as the critical micelle/aggregation concentration, the number of molecules (n) associated in the aggregate and the heat of aggregation. A complete thermodynamic description (ΔH, ΔS, ΔG, ΔCp) of the micellar colloids can be derived from the ITC data, allowing insights into the formation and stability of these colloidal systems. Based on the mass action model, taking into account counter ion binding, the ITC titration curves were simulated, and the aggregation number n of the aggregates derived. Isothermal titration calorimetry has a considerable advantage compared to other methods, because the critical micellisation concentration, the thermodynamic parameters of the aggregation process, and the aggregation numbers can be determined directly from one experiment.
Authors:J. Santos, Amanda Oliveira, C. Silva, J. Silva, A. Souza, and L. Lima
The kinetic and thermodynamic study of synthetic lubricant oils was
accomplished in this work, using isothermal and non-isothermal thermogravimetry
based on mass loss as a function of time and temperature. The thermodynamic
and kinetic behavior of the synthetic lubricant oils depends on atmosphere
and heating rates used in TG analysis. The kinetic and thermodynamic results
were satisfactory, presenting good correlation.
A thermodynamic study of the influence of the thermal treatments (annealing), below the glass transition temperature, on the
thermal behavior and enthalpy of maltitol glass was carried out by differential scanning calorimetry (DSC). An enthalpic effect
(exothermal) produced by the isothermal treatment of the quenched glass was found and measured.
The origin of the thermal effect was assigned to a physicochemical transformation of molecular associations in the solid (glass).
To achieve a correct description of the thermodynamic functions of glasses, another parameter, in addition to T and P, is introduced, namely the degree of advance of the above mentioned transformation.
This study is a part of a thermodynamic investigation of the R–Sn systems (R=La) [ 1 ] which is intended to give a better understanding of the constitutional properties and potential technological applications of
Authors:Li-Fang Song, Cheng-Li Jiao, Chun-Hong Jiang, Jian Zhang, Li-Xian Sun, Fen Xu, Qing-Zhu Jiao, Yong-Heng Xing, F. L. Huang, Yong Du, Zhong Cao, Fen Li, and Jijun Zhao
compounds have attracted many researchers’ attention [ 10 – 12 ]. Molar heat capacities of the materials at different temperatures are basic data in chemistry and engineering, from which many other thermodynamic properties such as enthalpy and entropy can be
Authors:A. Iddaoudi, N. Selhaoui, M. Ait Amar, K. Mahdouk, A. Aharoune, and L. Bouirden
This study is a part of a thermodynamic investigation of M–Pb systems (M = Yb [ 1 ], Ca [ 2 ], Ba [ 3 ]) already calculated in our laboratory which is intended to give a better understanding of the constitutional
Authors:Amar M. Ait, M. Idbenali, N. Selhaoui, K. Mahdouk, A. Aharoune, and L. Bouirden
This study is a part of a thermodynamic investigation of the Ru–R systems (R=Zr…) [ 1 ] which is intended to give a better understanding of the constitutional properties and potential technological applications of