Association phenomena in quaternized polysulfones/solvent/nonsolvent systems

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.Theoretical and experimental aspects on association phenomena generated by hydrogen bonding, dispersive and electrostatic interactions in ternary systems consisting of a proton-donor solvent (N,N-dimethylformamide or methanol), a proton-acceptor solvent (water), and a proton-acceptor polymer (polysulfone with different alkyl side chains), are investigated. In this context, binary and ternary thermodynamic interaction parameters are corrected on the basis of different association constants. Numerical values for these constants were evaluated as a function of the system composition, by mathematical simulations. As a result, mathematical simulations allow a good theoretical description of the preferential adsorption in agreement with experimental data.dc201

Enhancement of photoelectrochemical activity for water splitting by controlling hydrodynamic conditions on titanium anodization

This work studies the electrochemical and photoelectrochemical properties of a new type of TiO2 nanostructure (nanosponge) obtained by means of anodization in a glycerol/water/NH4F electrolyte under controlled hydrodynamic conditions. For this purpose different techniques such as Scanning Electronic Microscopy (SEM), Raman Spectroscopy, Electrochemical Impedance Spectroscopy (EIS) measurements, Mott-Schottky (M−S) analysis and photoelectrochemical water splitting tests under standard AM 1.5 conditions are carried out. The obtained results show that electron-hole separation is facilitated in the TiO2 nanosponge if compared with highly ordered TiO2 nanotube arrays. As a result, nanosponges enhance the photoelectrochemical activity for water splitting

Application of Fourier transform infrared (FTIR) spectroscopy in the characterization of tannins.

A review of vibrational frequencies reported for tannin molecules is provided to create a database with typical fingerprints for different types of tannins. This will provide researchers working on vibrational spectroscopy applications and technicians a fast, easy, and reliable method to assess the quality and authenticity of these compounds, both extracted in laboratories and provided from commercial sources. The widespread use of these compounds has highlighted the need for a systematic characterization of the vibrational frequencies and molecular fingerprints for their identification and discrimination. According to our knowledge, this is the first systematic collection of typical peak frequencies for tannins, which can be applied in several research fields and technological applications