Photodriven Self-Excited Hydrogel Oscillators

Self-excitation of smart materials that respond to stimuli is important for building soft robots capable of self-sustainable untethered locomotion. However, in these machines the sophisticated interaction and energy flow between materials and stimuli are not well understood. The authors study a self-excited hydrogel cantilever oscillator irradiated by constant light, and find that the synergy between the photoinduced moment and oscillation ensures positive work input into the cantilever to overcome damping. Scaling analysis of the energy flow of the system reveals how the stable oscillation amplitude is governed by various geometric and material parameters.