Transcript of Exploring Non-Linear Dynamics of Chemical Oscillator Networks
The goal of MRSEC is to produce purely synthetic materials that possess the attributes found in living organisms. This project aspired to create soft robots that emulate the sinuous motion of a swimming eel. In nature there are many systems that can be conceptualized as a network of discrete oscillating unites that have the ability to self- organize exhibiting collective behaviors in the form of spatiotemporal patterns. Such systems include, the neural tissue of an eel and fireflies. In order to gain a deeper understanding of their dynamics, we use a well characterized limit cycle oscillator, the Belousov–Zhabotinski or BZ reaction as our model system. This autocatalytic reaction oscillates between two visually discreet states as we can see here. But how can we form networks?
Networks of discrete BZ oscillators are formed by isolating BZ reactants in water in oil emulsion or using PDMS well lattices filled with the BZ reaction. Both PDMS and fluorinated oil are apolar materials allowing small less polar substances of BZ reaction to permeate through them resulting in a chemical coupling between the units. Networks with certain geometrical characteristics have different coupling mechanisms. Most of our experimental systems fall into two broad categories. The first is the excitatory coupling where the chemical coupling is mediated through the two excitatory components, the bromine dioxide radical and bromous acid, generating waves. The second is the inhibitory coupling where the inhibitory component, bromine, diffuses from one well to the other generating discrete oscillating patterns. By combining these two types of chemical coupling we were able to mimic a simple neural circuit, the CPG of an eel. At the steady state this network produces two waves that propagate from head to tail in antiphase synchrony. Inspired by this biological system our next step is to generate motion by using hydrogels that swell and deswell in response to the BZ reaction.
A National Science Foundation sponsored Material Research Science and Engineering Center
