Reversible formation of iron(III) ion clusters in the poly(acrylic acid)–Fe3+complex gel with changes in the water content

摘要: The hydrogel made by adding poly(acrylic acid)(PAA) to iron(III) chloride solution has been investigated as a function of the water content gel means EPR, visible and infrared spectroscopies. red–brown PAA–Fe3+ complex formed is homogeneous transparent solution, while xerogel obtained drying was yellow. Iron(III) ions in aggregate [as ion clusters] disperse (as mononuclear species) reversibly with repeated wetting gel. In hydrated PAA carboxyl groups bond strongly cluster ions, thus networks intermolecularly cross-linked cause gelation, whereas dry are loosened.