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It is fascinating but challenging to investigate the interaction induced the self-assembled structures, which always show novel properties. Cluster-shaped Zn-doped Fe3O4 self-assembled by nanosized particles exhibits high saturation magnetism and superparamagnetism. However, the interaction among these particles has not been reported as far as we know. At the present study, the transition from cluster-shaped to monodispersed Zn-doped Fe3O4 was successfully obtained through the addition of ethylenediamine (EDA). In situ calorimetric technology was used to study these formation processes. The results demonstrate that “-OCH2CH2O-” groups bond Fe3+ and Zn2+ ions together, which can be used to induce cluster-shaped sample formation. This study may give a route to synthesize self-assembled materials. [ABSTRACT FROM AUTHOR]

In situ calorimetric technology was firstly employed to study the effects of surfactants on the materials formation. In the present study, different kinds of surfactants were selected as additives during cluster-shaped Ni-doped Fe3O4 synthesis. Experimental results indicate that the surfactants reduced the particle size and changed the cationic distribution, compositions and magnetic properties of the as-synthesized materials. The microcalorimetric results demonstrate that the sample formation was endothermal and divided into five processes based on the heat-flow versus time curves. No significant effects of the surfactants on these processes were found. However, the surfactants addition affected the heat flow and the temperatures for peaks in these curves. The surfactant adsorption on the crystal facet and nuclei of the sample, and the interactions among surfactants and ions contained in the system may be mainly the reason for these effects. These results demonstrate different actions of surfactants and ligands on materials formation. [ABSTRACT FROM AUTHOR]

Molar heat capacity of the azeotropic mixture composed of water, n-propanol, and benzene was measured by an adiabatic calorimeter from 79 to 320 K. The glass transition and melting processes of the mixture were determined based on the curve of the heat capacity with respect to temperature. The glass transition occurred at 101.920 K. The melting processes took place in temperature ranges 258–268 and 268–279 K. The corresponding melting enthalpies and entropies were calculated to be 1.474 kJ mol−1, 5.508 J K−1 mol−1; 6.144 kJ mol−1, 22.28 J K−1 mol−1, respectively. The thermodynamic functions and the excess thermodynamic functions of the mixture relative to temperature 298.15 K were derived based on the relationships of the thermodynamic functions and the function of the measured heat capacity with respect to temperature. [Copyright &y& Elsevier]

The molar heat capacities of the azeotropic system (0.30 mol water+0.70 mol cyclohexane) were measured by an adiabatic calorimeter in temperature range of 78–320 K. The functions of the heat capacity with respect to thermodynamic temperature were established. The phase transition took place in temperature ranges of 184–190, 271–276 and 276–283 K corresponding to the solid–solid phase transition of cyclohexane, solid–liquid phase transition of water and solid–liquid phase transition of cyclohexane, respectively. The corresponding enthalpies and entropies of the phase transition were found to be 4.559 kJ mol−1, 24.510±0.065 J K−1 mol−1; 2.576 kJ mol−1, 9.454±0.041 J K−1 mol−1; and 2.040 kJ mol−1, 7.296±0.029 J K−1 mol−1, respectively. The thermodynamic functions and the excess thermodynamic functions of the azeotrope were derived based on the relationships of the thermodynamic functions. [Copyright &y& Elsevier]

The molar heat capacity of the binary system ethanol + benzene was measured by an adiabatic calorimeter in the temperature range from 80 to 320 K. The glass transition and phase transitions of the mixture were determined based on the curve of the heat capacity with respect to temperature. The glass transition occurred at 97.536 K, the enthalpy and entropy of the glass transition were calculated to be 1.796 kJ mol−1, 18.414 J mol−1 K−1, respectively. The phase transitions took place in temperature ranges 115.875–128.400, 146.778–159.015 and 256.645–274.981 K corresponding to the solid–solid phase transition of ethanol, solid–liquid phase transition of ethanol and solid–liquid phase transition of benzene, respectively. The corresponding enthalpies and entropies of the phase transition were calculated to be −1.266 kJ mol−1, −10.745 J K−1 mol−1; 2.166 kJ mol−1, 13.818 J K−1 mol−1; 5.390 kJ mol−1, 19.856 J K−1 mol−1, respectively. The thermodynamic functions and the excess thermodynamic functions of the mixture relative to standard temperature 298.15 K were derived based on the relationships of the thermodynamic functions and the function of the measured heat capacity with respect to temperature. [Copyright &y& Elsevier]

The molar excess heat capacity Cp, mEof(1 − x)H2O + xHOCH2CH2OH has been measured in the temperature range from 273.15 K to 373.15 K at 5 K intervals. The Cp, mEvalues are negative and positive at all compositions between temperatures of (273.15, 283.15, 333.15 and 373.15) K, respectively. BetweenT = 288.15 K and T = 328.15 K, Cp,mEvalues are positive for the mixtures rich in water and negative for the mixtures rich in ethylene glycol with maxima at values of x about 0.07, 0.3 and with minima at values of x about 0.6. The curve ofCp, mE against x at T = 303.15 K is unusual in showing three maximum values at values of x at about 0.07, 0.3, and 0.4, respectively. The curves ofCp, mE against T show that the effects of T onCp, mE at x = 0.03124, 0.5372, and 0.7232 are more complex. The shapes of the curves of Cp, mEagainst x and their changes with temperature can be accounted for by the structure of the binary system. [Copyright &y& Elsevier]

The heat capacities of two kinds of rare-earth element solid complexes with isoleucine [Re2(Ile)4(H2O)8](ClO4)6 (where Re=Nd, Er, and Ile=isoleucine) have been measured by an automatic adiabatic calorimeter in the temperature range from 80 to 370 K. Two solid–solid phase transitions were found from the Cp curve of Nd formed complex in the range of 165–175 K with a peak temperature of 167.88 K and in the range of 195–210 K with a peak temperature of 202.13 K. The corresponding molar enthalpies of these phase transitions were determined to be 404.61 J mol−1 and 2.955 kJ mol−1, respectively. One solid–solid phase transition was found for the Er formed complex in the range of 190–205 K with a peak temperature of 193.42 K. The corresponding molar enthalpy of this transition was 14.11 kJ mol−1. Smooth heat capacities and thermodynamic functions relative to the standard state (298.15 K), HT−H298.15, ST−S298.15 and −[GT−G298.15], of the two compounds, were calculated on basis of experimental heat capacity data. Possible mechanisms of thermal decompositions for the pair of compounds were suggested according to the thermogravimetric (TG) analysis. [Copyright &y& Elsevier]