Volumetric 3D‐Printed Piezoelectric Polymer Films

A novel additive manufacturing route using a tailored resin containing Poly(vinylidene fluoride) Trifluoroethylene (PVDF‐TrFE) to 3D print piezoelectric films is demonstrated. Piezoelectric films are printed within 2 seconds in a single step by simultaneously focusing initiating and inhibiting excitations within the liquid resin to locally confine the photochemical reaction. The printed films are patterned with an array of holes with a diameter of 30 µm and a pitch of 55 µm. The piezoelectric response is homogeneous across the film, indicating that the print pattern does not impact the PVDF‐TrFE microstructure. Although the printed films contain only a small volume fraction of PVDF‐TrFE (3 wt.%), their piezoelectric response (d33 = 20.3 pC/N) is comparable to the highest literature values reported for PVDF‐TrFE films. The printed PVDF‐TrFE films are predominantly β‐phase, and no electrical poling, post‐processing, piezoelectric or inorganic additives are used in the fabrication. Analysis using piezoresponse force microscopy (PFM) and scanning electron microscopy (SEM) reveals that the enhanced piezoelectric response is due to the preferential formation of oriented PVDF‐TrFE phases during printing. These results demonstrate how the dedicated design of photoactive resins in combination with volumetric additive manufacturing can be applied to rapidly fabricate functional 3D structures. 3D printing of piezoelectric PVDF‐TrFE films from a photochemical reaction. The microstructure films are printed in 2s by exciting the photo‐active resin with an initiating (go) and inhibiting (stop) excitation wavelength, respectively.