Naslov
Thermodynamics of Polyelectrolyte Complex Formation ; the Effect of Ionic Strength and Electrolyte Type

Autori
Požar, Josip ; Kovačević, Davor

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
24th Conference of the European Colloid and Interface Society : Book of Abstracts / - Prag, 2010

Skup
24th Conference of the European Colloid and Interface Society

Mjesto i datum
Prag, Češka Republika, 05.09.2010. - 10.09.2010

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Thermodynamics ; polyelectrolytes ; complexation

Sažetak
Since the introduction of multilayers in the early nineties[1], polyelectrolyte complexes and polyelectrolyte multilayers have become the subject of numerous investigations. Assemblies containing various types of polyelectrolytes in a wide range of conditions (pH, temperature, concentration and type of supporting electrolyte) have been prepared and studied using different experimental techniques. Although considerable progress in the field has been made, many fundamental questions considering the thermodynamics of both polyelectrolyte complexation and polyelectrolyte multilayer formation have remained unexplained. Among them, the role of both the electrolyte concentration and electrolyte type should be particularly stressed. A deeper thermodynamic insight into the influence ionic conditions (i.e. electrolyte type and concentration) on the process of polyelectrolyte complex formation can be provided by calorimetric investigations. Since polyelectrolyte complexation under different ionic conditions has hardly been explored by means of calorimetry[2, 3], we have systematically studied the complexation of poly(sodium 4-styrenesulfonate), Na+PSS−, with poly(allylamine hydrochloride), PAH+Cl−, in the presence of sodium salts that contain different mono- and divalent anions. The reversibility of complex formation and the influence of electrolyte concentration on thermodynamic parameters of complexation were also the subject of our investigations. The effect of polyelectrolyte concentration and chain length was studied as well. The complexes formed were found to be insoluble in the concentration range studied. The stoichiometry of formed complexes was always 1:1, or very close to that value. The obtained reaction enthalpies of complexation were very low in all cases. Enthalpograms obtained when PAH+Cl− solution was added to Na+PSS− solution and vice versa were notably different, suggesting the formation of different type of complexes when one of the polyelectrolytes is in excess. The reaction enthalpies obtained in the presence of different supporting electrolytes could be explained in terms of anion hydration enthalpies and the specific affinity of PAH towards different counterions.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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