Synergistic effect of barium titanate and insulating fillers on dielectric performance of sandwich-structured PLA composites

The polylactic acid (PLA) based sandwich-structured composites consisted of polydopamine (PDA) coated insulating fillers such as boron nitride (BN) and mica nanosheets dispersed in degradable PLA as the outer layer and PDA coated barium titanate (BT) dispersed in PLA as the middle layer. The sandwich-structure of PLA composites can enhance dielectric and energy storage performance. The energy density of PLA/40PDA@BT/ 8PDA@BN and PLA/40PDA@BT/8PDA@Mica composites are 2.23 and 1.72 J/cm3 respectively because the increase of energy density reflecting their high-field polarizable ability may be due to the interfacial polarization between fillers and PLA. The energy storage efficiency of PLA/40PDA@BT/8PDA@BN and PLA/40PDA@BT/ 8PDA@Mica are 40 and 83% respectively because PDA@Mica with the larger size of 3-4 mu m as insulated barriers can effectively restrain the leakage currents compared with PDA@BN with the size of 0.8-1.3 mu m.

Automated summary

The study showed that PLA-based sandwich-structured composites with PDA coated fillers exhibited enhanced dielectric and energy storage performance, with PDA@Mica fillers showing higher energy storage efficiency compared to PDA@BN fillers.