Synchronous volume and color self-oscillating gels based on chemomechanical coupling.

A novel Belousov-Zhabotinsky (BZ) gels which were observed volume and color self-oscillating periodically and autonomously in a closed homogeneous solution free of acid without any external stimuli were prepared successfully and the self-oscillating could last more than 3 h. The cross-linked gels are composed of a non-thermoresponsive and biocompatible poly(vinylpyrrolidone) (PVP), acrylic acid (AA) and 5-acrylamide-1,10-phenanthroline bis(1,10-phenanthroline) iron(II) (Fe(phen)₃), which act as the catalyst for the BZ reaction. The amplitude of the diameter oscillation for cylindrical gels was about 20 μm to approximately 5% of its initial diameter. The period of the volume oscillation was about 250 s. A moving chemical wave was observed directly propagation across cylindrical gels. The reversible changes in volume and color, the moving chemical wave in the gels have potential applications in the design of microfluidic devices and mass-transport systems under mild pH conditions. [ABSTRACT FROM AUTHOR]