Polarity and Temperature-Dependent Properties of Poly(N-isopropylacrylamide) and Poly(N,N-diethylacryl-amide) Hydrogels Studied by Liquid Chromatography |
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Authors: | Ji?í Hradil Hana Macková Daniel Horák |
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Institution: | Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic |
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Abstract: | Summary: Superporous N-isopropylacrylamide (NIPAAm) and N,N-diethylacrylamide (DEAAm) copolymers with N,N'-methylenebisacrylamide (MBAAm) were prepared by radical polymerization with the aim to determine their temperature-dependent changes in polarity by liquid chromatography. Superpores were formed by the salt-leaching technique using NaCl as a porogen. Porosities of the hydrogels characterized by water regain and mercury porosimetry, ranging from 81 to 91%, were proportional to the volume of NaCl porogen in the feed. The retention volumes of several phenols decreased with increasing temperature as polarity of the hydrogels decreased. A jump change in solute retention volume was observed at ca. 32 °C in PNIPAAm and at ca. 35 °C in PDEAAm indicating a change in the mechanism of interaction. The Gibbs energy changes ΔGCH2 were rather low, increasing in the order phenol < benzyl alcohol < ethanol < butan-1-ol. In contrast to the solutes, retention volumes of bovine serum albumin and dextrans were higher at higher temperature confirming thus hydrophobic interactions of the compounds with the studied hydrogels. |
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Keywords: | albumin dextran liquid chromatography polyacrylamides retention temperature-sensitive |
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