Novel strategy for the ionotropic crosslinking of chitosan–alginate polyelectrolyte complexes



The formation kinetics of chitosan–alginate polyelectrolyte complex (CAPEC) was investigated in the presence of various ionic crosslinkers. The effects of binary mixtures of some anions with Ca2+ cations were also studied as a novel application. CAPEC gelation was enhanced in cases where Ca2+ ions coexisted with anionic crosslinkers compared to their conventional individual use, and this resulted in dispersions with higher stability. We demonstrated that the effects of some anions on CAPEC gelation could be reversed in the presence of Ca2+ ions, such that the inhibitory anions became enhancers. The results also revealed that Ca2+ ions, the most widely used ionic crosslinkers in CAPEC synthesis, exerted inhibitory effect on CAPEC gelation at low concentrations; in addition, the use of Ca2+ ions alone resulted in decreased dispersion stability. The effects of the binary crosslinker on the structure and properties of CAPEC were studied by scanning electron microscopy, Fourier transform infrared spectroscopy, particle size analysis, and ζ-potential analyses. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 40019.