Modified Aliphatic Ionenes. Influence of Charge Density and Length of the Chains on Complex Formation with Poly(methacrylic acid)

Abstract

Modified ionenes were obtained by alkylation of terminal amino groups of aliphatic ionenes with p-nitrotoluene bromide. The modification endowed the ionenes with relatively high absorbance in UV-range of spectrum. The advantages of the modified ionenes were demonstrated, i.e. the possibility of highly accurate determination of the ionene concentration in dilute aqueous solutions from UV-spectra, fractionation of the sample by ion-exchange chromatography in NaCl gradient with UV-detection, estimation of a polymerization degree of the obtained fractions by “end groups” method and studying of polyelectrolyte complex formation with pyrenyl-tagged poly(methacrylic acid) by fluorescence quenching technique. Chain length and charge density of the ionene were shown to be the factors controlling both solubility and dissociation of the polyelectrolyte complexes in water-salt media. The data obtained strongly suggest that the main regularities ascertained for polyelectrolyte complexes are applicable to the ionene-containing systems, even though the ionene samples contained at most 32 charges in the chains. The revealed possibility of preparing ionene-containing PEC of desired stability, which can be varied in a wide range of ionic strength, including physiological one demonstrates potential of the modified ionenes as components of self-assembly and self-adjustment systems attractive for biomedical applications.