Tailored wrinkles for tunable sensing performance by stereolithography

Conducting polymer hydrogel can address the challenges of stricken biocompatibility and durability. Nevertheless, conventional conducting polymer hydrogels are often brittle and weak due to the intrinsic quality of the material, which exhibits viscoelasticity. This property may cause a delay in sensor response time due to hysteresis. To overcome these limitations, we have designed a wrinkle morphology three-dimensional (3D) substrate using digital light processing technology and then followed by in situ polymerization to form interpenetrating polymer network hydrogels. This novel design results in a wrinkle morphology conducting polymer hydrogel elastomer with high precision and geometric freedom, as the size of the wrinkles can be controlled by adjusting the treating time. The wrinkle morphology on the conducting polymer hydrogel effectively reduces its viscoelasticity, leading to samples with quick response time, low hysteresis, stable cyclic performance, and remarkable resistance change. Simultaneously, the 3D gradient structure augmented the sensor's sensitivity under minimal stress while exhibiting consistent sensing performance. These properties indicate the potential of the conducting polymer hydrogel as a flexible sensor.