Optimization of piezoelectric polymer composites and 3D printing parameters for flexible tactile sensors

Optimization of the formulation and processability of 3D-printable ceramic polymer composites offers a solution to piezoelectric materials with high printability and piezoelectric responses. Our approach is based on both 3D-printable piezoelectric composite formulation and auxetic structural design. The optimal formulation exhibited strong interfacial adhesion, high dispersion stability, low viscosity, and a smooth surface, resulting in a high piezoelectricity. In addition, processing parameters, such as the intensity and application time of the UV laser, were optimized for processability. The simulated structures were designed to further enhance the piezoelectric response, and several auxetic structures were compared. A printed piezoelectric composite with an auxetic structure, including a functionalized piezoelectric ceramic powder and a dispersant, showed good flexibility, a high piezoelectric coefficient (d₃₃), and an increased piezoelectric voltage output that was approximately three times larger than that of a typical flat structure. The proposed sensor based on the 3D-printed piezoelectric composite with the auxetic structure exhibited a high open-circuit voltage and can be used as a high-performance tactile position sensor. This work demonstrates that a 3D-printed piezoelectric composite can realize flexible and complicated structures with a high piezoelectric response and printability to enable flexible self-powered electronics and sensors.