posted on 2024-02-22, 15:06authored byBaptiste Blanc, Zhenkun Zhang, Eric Liu, Ning Zhou, Ippolyti Dellatolas, Ali Aghvami, Hyunmin Yi, Seth Fraden
We report on a synthesis protocol, experimental characterization,
and theoretical modeling of active pulsatile Belousov–Zhabotinsky
(BZ) hydrogels. Our two-step synthesis technique allows independent
optimization of the geometry, the chemical, and the mechanical properties
of BZ gels. We identify the role of the surrounding
medium chemistry and gel radius for the occurrence of BZ gel oscillations,
quantified by the Damköhler number, which is the ratio of chemical
reaction to diffusion rates. Tuning the BZ gel size to maximize its
chemomechanical oscillation amplitude, we find that its oscillatory
strain amplitude is limited by the time scale of gel swelling relative
to the chemical oscillation period. Our experimental findings are
in good agreement with a Vanag–Epstein model of BZ chemistry
and a Tanaka Fillmore theory of gel swelling dynamics.