Effect of ceramics/polymer heterointerface on dielectric property of self-assembled BaTiO₃/poly-L-lactic acid composite materials

Abstract

The dispersion state of barium titanate (BT) particle groups in self-assembled BT/poly-L-lactic-acid (PLLA) composites prepared under different fabrication conditions was investigated. In particular, the BT/PLLA/BT heterointerface in the BT aggregates by the self-assembly process was analyzed and the effect of the BT/PLLA/ BT heterointerface and the BT/BT interface on the dielectric properties of BT/PLLA composites were investigated. BT/PLLA composites were fabricated by adding BT particles and BT granules with low and high-speed kneading conditions. The volume fraction of BT in composites varied from 5 to 20 vol.%. The BT aggregates having a BT/PLLA/BT heterointerface were formed under the low-speed kneading condition and the BT agglomerates having a BT/BT interface were formed under the high-speed kneading condition within the selfassembly process. The tan ¤ of the BT/PLLA composite of self-assembled BT aggregates having the BT/PLLA/ BT heterointerface was lower than that of the BT granules having the BT/BT interface. The dielectric constant (¾¤) of the self-assembled composite was increased by growing an average secondary particle area of BT fillers. In contrast, the average secondary particle area of BT granules was increased, as compared with 5 vol.% of BT. However, the change in ¾¤ was saturated. The slopes of the change in the ¾¤ depending on the secondary particle area of BT fillers were different between the self-assembled BT aggregates having the BT/PLLA/BT heterointerface and the BT granules having the BT/BT interface. Thus, it was suggested that it was an important role in improving the dielectric properties to form ceramic secondary particle groups having the ceramics/polymer/ceramics heterointerface by the self-assembly process.

Effect of dispersant viscosity for self-assembly process of barium titanate aggregates in material texture of polyvinylidene fluoride composites —evaluation of multifractal dimension (<i>D_q</i> [<i>q</i> = 0, 1, 2]) and dielectric properties—

“…In a previous report, it was suggested that the electric dipole of a BT/ polymer/BT heterointerface can be induced by improving the ¾B. 8) In fact, when BT granules with a BT/BT interface were added, the S was found to be large, while the change in the ¾B was found to be saturated. 8) In our results for the S and ¾B of the samples with PEG2000 and PEG20000 (Fig.…”

“…8) In fact, when BT granules with a BT/BT interface were added, the S was found to be large, while the change in the ¾B was found to be saturated. 8) In our results for the S and ¾B of the samples with PEG2000 and PEG20000 (Fig. 5), it was clear that the S increased with the increase in PEG viscosity.…”

“…The air might enter the BT/PVDF composites in the kneading process in air. In a previous report, 8) the dielectric properties of the self-assembled BT/PLLA composites were investigated. The dielectric constant of air is lower than PLLA and BT.…”

“…7) In a previous report, we outlined how the BT/ PLLA/BT heterointerface formed within the kneading process via the self-assembly process and demonstrated that this has an important role in improving the ¾B. 8) A method incorporating fractal analysis was devised to quantitatively analyze the shape of particles, 9) with Kobayashi et al 10) investigating the grain boundary microstructures in SUS316L stainless steel using the fractal analysis method. Here, the authors highlighted how the maximum random boundary connectivity was found to have a fractal nature in the SUS316L specimens and suggested that it was possible to characterize the grain boundary microstructures via fractal analysis.…”

Defect chemistry in perovskite ferroelectrics—History, present status, and future prospects—

“…À ¢T =kT g; ð4Þ where N C (T ) and N V (T ) are the effective densities of states in the conduction band and the valence band, respectively 27) and k the Boltzmann constant, E g (0 K) the band gap at 0 K 36), 37) and ¢ its temperature coefficient. 110) The formation of V O by the oxygen kinetics is written as…”