INVESTIGATION OF ELECTRET PROPERTIES OF POLYLACTIDE PLATES WITH AIR CAVITIES OBTAINED BY 3D PRINTING

Abstract

Polymer electrettes are becoming key materials for creating sensors and piezoelectric devices in electronics. 3D printing technology opens up new possibilities for the formation of complex electret structures with an adjustable microstructure, including the creation of samples with air cavities. The purpose of this work is to study the effect of the structure of polylactide plates obtained by layer-by-layer deposition with a different number of air cavities on their electret (surface potential) and piezoelectric (piezoelectric effect d33) properties. The results of the study showed that plates printed from colored filaments exhibit better electret and piezoelectric characteristics than those made from natural polylactide, probably due to the formation of unique charge traps at the polymer–dye phase boundary. The air cavities in the volume of polylactide plates contribute to an increase in the stability of the electret charge by creating additional charge traps, which manifests itself in an increase in the surface potential at the stage of its stabilization, but only to a certain content (50% in the middle layer of the plates), exceeding which leads to a deterioration in electret properties associated with insufficient the amount of polymer material and the possible violation of the integrity of the upper layer of the plates. The work demonstrates the prospects of using additive technologies to create functional polymer electret materials for electronic devices.