Facilely fabricated Janus polymer film for actuator and self-powered sensor

Janus polymer films (JPFs) have drawn increasing attention recently, owing to their distinct surface performance and potential applications. However, it still remains challenged to fabricate robust JPFs for actuator and selfpowered sensor by a facile method. Herein, via facile vacuum-assisted hot-compressing method (VAHM) and spray coating, JPFs were successfully prepared, whose electrode and piezoelectric/actuation layer are respectively single-walled carbon nanotubes (SWCNTs) layer and micropatterned polyvinylidene fluoride (PVDF) layer. Moreover, JPFs show decent actuation performance (bending to 990 degrees in 0.93 s) because of high molecular orientation level and asymmetric swelling of micropatterned surfaces. Meanwhile, such JPFs show rapid selfpowered sensing property (response and recovery time of 1.3 s and 1.2 s, respectively) when deformed in acetone vapor, because of the inherent piezoelectricity of PVDF. Accordingly, a real-time acetone monitoring (RTAM) system was successfully constructed in virtue of Internet of Things (IoT) technology. This work proposes a facile way to develop low-cost and durable JPFs, and further combines actuation performance with selfpowered sensing property, paving a creative way to construct functional architecture based on the concept of polymer "structuring" processing.