Solution Properties of Intramolecularly Crosslinked Polyelectrolyte.

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The present study was carried out to clarify the mutual interaction in the polymer solution from view point of the intrachain crosslinks, polyelectrolyte, and interaction among counterions.About an interesting polyelectrolyte solution behabior observed in aqueous poly(vinyl alcohol)(PVA)/Borax(Na_2B_4O_7) systems, the following experimental facts were revealed : 1, complexations(mono-diol and di-diol) of PVA with borate ion, B(OH)_4^-, which introduce simultaneously the charges and crosslinks to the PVA chain, occur only intramolecularly, being unchanged the molecular weight of PVA. 2, the formation constants of both complexes decrease sharply with borax concentration C_b and this decrease levels off at higher C_b, as well as the second virial coefficient does.These results can well interpret the polyelectrolyte behaviorof PVA/Borax systems in terms of a favorable balance between expansion due to charges and contraction due to intrachain crosslinks in the complexed PVA. Also, the mutual charge repulsion between the complexing borate ion and the charges on the complexed PVA chain depresses strongly a further complexation onto the PVA chain.In relation to the above-polyelectrolyte solution behavior, we found also that a relatively small hydrophobic ion(ethylbenzensulfonate anion), which has not self-association ability itself, can associate each other around a polyion(poly(allylammonium)cation)through its hydrophobic interaction.