Dr. Matthew Smith
Stimuli responsive polymer gels, in which a single stimulus (e.g. temperature, pH, etc.) causes a change in volume, have been the subject of intense interest for applications such as drug delivery and biological sensors. In these gels a periodic external change in stimulus is required for a periodic oscillation to be observed within a gel. However, many biological systems maintain periodic oscillations under constant environmental conditions, transforming chemical energy into mechanical work. Materials capable of mimicking this biological behavior represent exciting opportunities for extending responsive behavior through chemical energy harvesting and autonomous function. Autonomous oscillations can be achieved by the oscillating Belousov-Zhabotinsky (BZ) reaction within gels containing the BZ catalyst. When a gel containing a catalyst metal, such as ruthenium, is placed in a solution containing the BZ reactants (minus the Ru), the catalyst within the gel undergoes oscillation in its redox state. Due to the difference in the hydrophilicity of the polymer network at the Ru2+ and Ru3+ states, the gel displays swell-deswell oscillations. One of the challenges in producing self-oscillating gels is the lack of options for BZ catalysts. Currently used catalysts are either cost prohibitive or overly difficult to synthesize. To alleviate this problem, a facile, relatively inexpensive synthesis of ruthenium catalyst complex was attempted following previously reported procedures in the coordination polymer literature. Using readily available precursors, cis-Dichlorobis(2,2’-bipyridine)ruthenium(II) and poly(4-vinylpyridine) a ruthenium-poly(vinylpyridine) (RuPVP) metallopolymer was prepared. BZ reactions were successfully triggered by this ruthenium catalyst. With the catalytic ability of RuPVP established, this research can proceed with grafting the catalyst into a polymer gel, creating a versatile and accessible self-oscillating gel.
Repository citation: Kim, Minchul, "Ruthenium-Poly(Vinyl Pyridine) (RuPVP) Metallopolymers for Catalyzing Self-Oscillating Gels" (2014). 13th Annual Celebration of Undergraduate Research and Creative Performance (2014). Paper 62.
April 11, 2014. Copyright © 2014 Hope College, Holland, Michigan.