posted on 2022-12-14, 14:33authored byJun Ding, He Ma, Xiao Xiao, Qingwei Li, Kai Liu, Xinping Zhang
A flexible actuator, which can convert external stimuli
to mechanical
motion, is an essential component of every soft robot and determines
its performance. As a novel two-dimensional material, MXene has been
used to fabricate flexible actuators due to its excellent physical
properties. Although MXene-based actuators exhibit excellent actuation
performance, their bending deformation is solely due to the in-plane
isotropy of the MXene film, and an MXene torsional actuator has not
been reported. This study presents a flexible torsional actuator based
on an MXene–carbon nanotube (CNT)–paraffin wax (PW)
film. In this actuator, the MXene thin film acts as a light absorption
layer with wavelength selectivity, superaligned CNT provides structural
anisotropy for the composite film, and PW acts as the active layer.
The chirality and helical structure of the actuator could be tuned
by the orientation of the CNT film. Such an actuator delivers excellent
actuation performance, including high work density (∼1.2 J/cm3), low triggering power (77 mW/cm2), high rotational
speed (320°/s), long lifetime (30,000 cycles), and wavelength
selectivity. Inspired by vines, we used the torsional actuator as
a spiral grabber, which lifted an object that weighs 20 times more
than the actuator. The high-performance torsional actuator would be
potentially used as a noncontact sensor, rotary motor, and grabbing
tool in the soft robot system.