Swelling/deswelling self-oscillating of microgels induced by the BZ reaction with Fe(phen)3 catalyst

A novel kind of microgels, poly(NIPAAm- co -Fe(phen) 3 - co -AAc), were prepared by copolymerization N -isopropylacrylamide (NIPAAm), acrylic acid (AAc) and iron(II) 5-acrylamide-1,10-phenanthroline-bi(1,10-phenanthroline) (Fe(phen) 3 ), the catalyst for the Belousov-Zhabotinsky (BZ) reaction. The microgels were characterized by FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS) and scanning electron microscope (SEM). In addition, the self-oscillating behaviors of the microgels were investigated in BZ system free of catalyst. Both the redox potential and transmittance self-oscillation were observed. Moreover, the amplitudes of poly(NIPAAm- co -Fe(phen) 3 - co -AAc) microgels are much larger than those of linear polymer and gel. This advantage originated from the special structure, size and composition of the microgels.