Micropatterning of Highly Stretchable Tough Polymer Actuators for Multistage Detection of Acetone Vapors.

Micropatterning of soft polymer actuators is an emerging technique that overcomes many drawbacks of macroscopic patterning to trigger the shape-programmable deformations for various functional applications. We thus report a polymer composite actuator that combines micropatterning with high stretchability and toughness, whereupon it demonstrates shape-programmable deformation, and can be utilized in an electronic device for multistage detection of acetone vapors. The actuator is created by alignment of Fe(0) particles (FePs) into poly(vinylidene difluoride) (PVDF) matrix in a strong magnetic field, followed by stretching the PVDF/FePs film into necking structure. The necking induces more-directional alignments of FePs and further crystallization of PVDF, so that bringing PVDF/FePs actuator with anisotropic elastic tensors, resulting in controllable shape deformation upon sorption of acetone vapors. Assisted by magnetic field, acetone-driven deformation can be transferred to directional movement by rolling over a substrate. Micropatterned PVDF/FePs actuator is stretchable and tough, with maximum stress reaching 160 MPa at the rupture strain of 100%, making it capable of continuous deformation for several hours, or even longer, depending on the concentration of acetone vapors. This directional reversible fatigueless response is involved in a smart controller that exhibits promising potential for multistage detection of acetone vapors.