3D‐Printing of Highly Piezoelectric Barium Titanate Polymer Nanocomposites with Surface‐Modified Nanoparticles at Low Loadings

This work describes the development and characterization of tetragonal barium titanate nanoparticles (BTO NPs) and their surface functionalization with dopamine dodecylamine (DDA), a lipophilic organic ligand. The so-obtained lipophilic NPs (BTO-DDA) are then formulated at low loadings (< 5 wt.%) into liquid photocurable resins for vat photopolymerization (VP) and 3D printed into solid objects. The printed composites are mechanically characterized in order to assess the effect of the nanomaterial on the mechanical properties of the 3D printed polymer, revealing no significant variations in the mechanical properties (tensile or flexural) of the nanocomposites compared to the original polymer matrix. In light of these results, the printed nanocomposites are studied in terms of their capacity to generate a separation of charge by the piezoelectric effect, typical of the BTO crystal structure. This study reveals that BTO-loaded nanocomposites display outstanding piezoelectric coefficients as high as 50 pC/N when BTO-DDA is formulated at 3.0 wt.%, only slightly less than one-third of the piezoelectric coefficient previously reported for bulk BTO, while preserving the mechanical properties of the polymer matrix.