Generating induced current through the diving-surfacing motion of a stimulus–responsive smart device

Abstract

Energy conversion from chemical to mechanical forms and then to electricity has experienced an explosive development in recent years. However, most of the current studies are challenged by producing a high output of induced current through cutting the strong magnetic line with a conductive line. Herein, we designed and fabricated a mini-generator to perform a diving-surfacing cycled motion with an intelligent initiation based on pH-responsive materials, and the obtained mechanical energy can be converted into electricity through cutting the strong magnetic line with a conductive line. Under acidic conditions, the device floated on the surface of water, and its locomotion was switched on through the addition of a basic solution. The re-float process was initiated by adding an acid solution and hydrogen peroxide. By investigating the influencing factors of the smart motion, we found that the device that consisted of one pH-responsive part, one hydrophobic part and a quartz cell performed the best under a 0.9% concentration of hydrogen peroxide during the diving-surfacing motion with a high frequency, leading to the highest output of induced current. Moreover, the device with bilateral-pyramidic structure provided the highest diving-surfacing frequency and maximized vertical motion velocity because of its drag-reducing property, achieving the highest output of induced electromotive force.