RESUMEN
Multistimuli responsiveness and programmable shape recovery are crucial for soft actuators in soft robotics, electronics, and wearables. However, existing strategies for actuation cannot attain power-free shape retention after removing the external energy supply. Here, a self-assembled density deposition method was developed to fabricate an electrothermal-NIR-magnetic triple-response actuator which was composed of cellulose nanofiber/poly(vinyl alcohol)/liquid metal (CNF/PVA/LM) and magnetic polydimethylsiloxane (MPDMS) layer. Interestingly, the large deformation can be controllably fixed and the temporary configuration will be programmable recovered under a magnetic field due to the thermal-plastic transferring behavior of the CNF/PVA/LM. Rolling robot prepared based on soft actuators exhibits good ability to avoid obstacles. In addition, the object handling and programmable release capabilities of the carrier robots demonstrate that this actuation approach will contribute to a better understanding of how to more rationally utilize various stimuli for application purposes.
RESUMEN
Magnetorheological elastomer (MRE) is a kind of smart material, whose mechanical property can be controlled by the external magnetic field quickly and reversibly. The damping property of MRE is one of the most concerned properties when designing MRE based devices. In this work, the influence of gamma radiation on the damping property of MRE was investigated. Six different exposures of gamma radiation were applied to the MRE samples. The highest gamma radiation dose was up to 1 × 105 Gy(Si), which can cover most of the engineering application scenarios. The influence of gamma radiation on the damping-strain relation and the damping-magnetic-field relation were studied. The probable mechanisms were discussed in detail. It is found that the gamma radiation does not affect the variation trend of loss factor of MRE with increasing strain amplitude or magnetic flux density. But it affects the variation trend of the maximum change of strain-induced or magnetic-field-induced loss factor of MRE. Besides, with constant strain and constant magnetic flux density, the loss factor of MRE shows w-shape variation trend with increasing gamma radiation dose. It is considered to be resulted from the combined action of the intrinsic damping and the interfacial friction damping of MRE.