am9b06398_si_009.mp4 (4.11 MB)
Programmable Polymer Actuators Perform Continuous Helical Motions Driven by Moisture
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posted on 2019-05-15, 00:00 authored by Qing Chen, Xiunan Yan, Han Lu, Ning Zhang, Mingming MaPowerful soft actuators that can
perform programmable actuations
are highly desired for the development of soft robotics. Herein, we
report a moisture-driven polymer actuator, PPA, which is a composite
of poly(3,4-ethylenedioxythiophene)/polyvinyl alcohol/copolymer of
acrylic acid and 2-acrylanmido-2-methylpropanesulfonic acid. PPA can
not only generate powerful actuation with a contractile stress up
to 13 MPa, but can also perform programmable helical motions. PPA
films with internal stress along the radial directions were prepared
by a simple solution-casting method. Driven by moisture, rectangular
strips cut from the same PPA film but with different cutting angles
(the oblique angle between the long axis of the PPA strip and the
radial axis of the PPA film) can perform direct bending and left-handed
or right-handed helical motions, demonstrating the generation of chirality
from asymmetric internal stress. By modulating the distribution of
internal stress in PPA strips, their moving direction and speed are
readily prescribed. The powerful and programmable PPA strips can be
used to make soft devices, such as moisture-responsive switches and
transporters. Our strategy of generating and utilizing internal stress
in responsive polymers represents a promising platform for fabricating
smart soft actuators.