(77e) Harnessing Light to Guide the Motion of Chemo-Responsive Polymer Gels

Irritability, a response to avoid adverse environmental conditions, is one of the hallmarks of all living organisms. Polymer gels which undergo self-sustained oscillations, by virtue of Belousov-Zhabotinsky (BZ) reaction, are the prefect candidate for designing such ?irritable? man-made systems. Driven by the periodic reduction and oxidation of the BZ catalyst that is grafted on the polymer backbone, these BZ gels undergo rhythmic swelling and de-swelling, which in turn can be controlled by using light as an external stimuli. Using our recently developed 3D gel lattice spring model (gLSM), which couples BZ reaction kinetics to gel dynamics, we simulate the response of BZ gels to non-uniform illumination. We demonstrate that these BZ gels exhibit autonomous motion away from light and in doing so it can bend, reorient and turn in a specific direction. In effect, the BZ gels are guided along the ?dark trail? in a manner dependent upon the intensity profile of the incident light. By simply manipulating the intensity profile of light we can also ?freeze? the movement of BZ gels and as a consequence, trap it at the desired location. Our findings provide guidelines for designing ?soft-active? materials that exhibit biomimetic functionality.