TY - JOUR
T1 - Swelling dynamics of zwitterionic copolymers: The effects of concentration and type of anion and cation
AU - de Grooth, Joris
AU - Ogieglo, Wojciech
AU - de Vos, Wiebe Matthijs
AU - Girones nogue, Miriam
AU - Nijmeijer, Dorothea C.
AU - Benes, Nieck Edwin
PY - 2014
Y1 - 2014
N2 - The effect of different salts and their concentration on the swelling of zwitterionic copolymers has been investigated for bulk polymer samples as well as for thin films. Relatively low ratios of the zwitterionic monomer already radically change the swelling properties of the copolymer. Increasing the NaCl concentration results in a significant increase of the swelling, which is indicative of the so-called anti-polyelectrolyte effect. The dynamic swelling experiments on the thin film show that only at high NaCl concentrations, the swelling is limited by solute diffusion. These swelling characteristics are distinctly affected by the type of ions present in the aqueous solution. The changes in maximum swelling degree are most sensitive to the type of anion, where the order of the extent of the effect of the anions follows the Hofmeister lyotropic series. For different cations, smaller changes in maximum swelling degree are found that only partially comply with the Hofmeister series. In most cases similar semi-Fickian swelling behavior is found, except in the case of LiCl concentrations above 0.8 M, where anomalous sigmoidal swelling curves are obtained. This behavior in high LiCl concentrations can be explained by the loss of interchain molecular interactions during swelling. This work provides meaningful insights on the behavior of zwitterionic copolymer films for applications such as membrane filtration that utilize different ions and ionic strengths.
AB - The effect of different salts and their concentration on the swelling of zwitterionic copolymers has been investigated for bulk polymer samples as well as for thin films. Relatively low ratios of the zwitterionic monomer already radically change the swelling properties of the copolymer. Increasing the NaCl concentration results in a significant increase of the swelling, which is indicative of the so-called anti-polyelectrolyte effect. The dynamic swelling experiments on the thin film show that only at high NaCl concentrations, the swelling is limited by solute diffusion. These swelling characteristics are distinctly affected by the type of ions present in the aqueous solution. The changes in maximum swelling degree are most sensitive to the type of anion, where the order of the extent of the effect of the anions follows the Hofmeister lyotropic series. For different cations, smaller changes in maximum swelling degree are found that only partially comply with the Hofmeister series. In most cases similar semi-Fickian swelling behavior is found, except in the case of LiCl concentrations above 0.8 M, where anomalous sigmoidal swelling curves are obtained. This behavior in high LiCl concentrations can be explained by the loss of interchain molecular interactions during swelling. This work provides meaningful insights on the behavior of zwitterionic copolymer films for applications such as membrane filtration that utilize different ions and ionic strengths.
KW - IR-95022
KW - METIS-307371
U2 - 10.1016/j.eurpolymj.2014.03.021
DO - 10.1016/j.eurpolymj.2014.03.021
M3 - Article
VL - 55
SP - 57
EP - 65
JO - European polymer journal
JF - European polymer journal
SN - 0014-3057
ER -