Belousov-Zhabotinsky autonomic hydrogel composites: Regulating waves via asymmetry
نویسندگان
چکیده
Belousov-Zhabotinsky (BZ) autonomic hydrogel composites contain active nodes of immobilized catalyst (Ru) encased within a nonactive matrix. Designing functional hierarchies of chemical and mechanical communication between these nodes enables applications ranging from encryption, sensors, and mechanochemical actuators to artificial skin. However, robust design rules and verification of computational models are challenged by insufficient understanding of the relative importance of local (molecular) heterogeneities, active node shape, and embedment geometry on transient and steady-state behavior. We demonstrate the predominance of asymmetric embedment and node shape in low-strain, BZ-gelatin composites and correlate behavior with gradients in BZ reactants. Asymmetric embedment of square and rectangular nodes results in directional steady-state waves that initiate at the embedded edge and propagate toward the free edge. In contrast, symmetric embedment does not produce preferential wave propagation because of a lack of diffusion gradient across the catalyzed region. The initiation at the embedded edge is correlated with bromide absorption by the inactive matrix, which locally elevates the bromate concentration required for catalyst oxidation. The competition between embedment asymmetry and node geometry was used to demonstrate a repeatable switch in wave direction that functions as a signal delay. Furthermore, signal propagation in or out of the composite was demonstrated via embedment asymmetry and relative dimensions of a T-shaped active network node. Overall, structural asymmetry provides a robust approach to controlling initiation and orientation of chemical-mechanical communication within composite BZ gels.
منابع مشابه
Belousov-zhabotinsky Autonomic Hydrogel Composites: Regulating Waves via Asymmetry (postprint)
متن کامل
Post-self-assembly cross-linking of molecular nanofibers for oscillatory hydrogels.
After a polymerizable hydrogelator self-assembles in water to form molecular nanofibers, post-self-assembly cross-linking allows the catalyst of the Belousov-Zhabotinsky (BZ) reaction to be attached to the nanofibers, resulting in a hydrogel that exhibits concentration oscillations, spiral waves, and concentric waves. In addition to the first report of the observation of BZ spiral waves in a hy...
متن کاملFabrication of quasi-two-dimensional, heterogeneously curved Belousov–Zhabotinsky systems
For many years the Belousov–Zhabotinsky reaction has been used to explore the large variety of dynamical behavior of excitation waves. The understanding of chemical waves can be applied to other physical and biological systems. Most theoretical and experimental work has been done in planar media, whereas for nonplanar systems there exist many theoretical but only very few experimental studies. ...
متن کاملA model for jumping and bubble waves in the Belousov–Zhabotinsky- aerosol OT system
We develop a four-variable model, based on the classic Field–Kőrös–Noyes mechanism for the oscillatory Belousov-Zhabotinsky BZ reaction, that describes recently discovered jumping waves and bubble waves in the BZ reaction in aerosol OT microemulsion and provides insight into their origins. Contrary to suggestions based on previous models, it appears that these phenomena can arise from interacti...
متن کاملComparative Analysis of Packet and Trigger Waves Originating from a Finite Wavelength Instability
The finite wavelength instability generates trigger and packet waves in an extended three-variable Brusselatortype model. The trigger waves account for experimentally observed stacking (shock) structures and acceleration of oncoming waves before collision observed in the Belousov-Zhabotinsky system. Packet waves exhibit specular reflection from surfaces. The mouth of a narrow tube connected to ...
متن کامل