Naslov
Calorimetric and Potentiometric Investigation of Interactions between Poly(sodium 4- styrenesulfonate) and Different Cations

Autori
Požar, Josip ; Kovačević, Davor

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

Izvornik
22nd Conference of the European Colloid and Interface Society : Book of Abstracts / Adamczyk, Zbigniew ; Barbasz, Jakub ; Nattich, Malgorzata ; Szatkowska, Katarzyna - Krakov : Institute of Catalysis and Surface Chemistry, 2008, 599-599

ISBN
978-83-60514-08-5

Skup
22nd Conference of the European Colloid and Interface Society

Mjesto i datum
Kraków, Poljska, 02.09.2008. - 04.09.2008

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Poly(sodium 4-styrenesulfonate) ; Calorimetry ; Potentiometry

Sažetak
When dissolved in polar solvents strong polyelectrolytes become highly charged due to the complete dissociation of functionalized monomer subunits. The homogenously distributed chain charge in solution increases both repulsive (between like charged monomer groups) and attractive electrostatic interactions (between monomers and counterions) resulting in highly nonhomogeneous counterion distribution around the polymer. Consequently, the counterions in the proximity of polyelectrolyte become either physically (condensed) or thermodynamically bound to polymer chain. It is known that the counterion binding depends on the charge and size of counterions, nature and charge of functional groups, concentration of polymer and the type of solvent used. In order to gain a deeper thermodynamic insight into effects of an electrolyte added to aqueous solution of strong polyelectrolyte we performed potentiometric and microcalorimetric titrations of poly(sodium 4-styrenesulfonate), Na+PSS-, with different alkali, earth-alkali and tetraalkylammonium salt solutions. Potentiometric titrations using sodium ion selective electrode have revealed that addition of electrolyte is accompanied by the increase in sodium activity until a certain critical value is reached. That critical value (the break in titration curves) depends on the charge number of the cation used. It is temping to conclude that such behaviour is due to the counterion substitution. The calorimetric titrations of Na+PSS- with the same electrolytes as stated above confirm that the measured enthalpy changes could be related to the counterion substitution observed potentiometrically. The calorimetrically observed differences in sign and magnitude of enthalpy change upon addition of various electrolytes and corresponding differences in counterion affinities can be explained by the differences in cation hydration.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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