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—

Abstract

In this paper, the properties of the barium titanate (BT)/polyvinylidene fluoride (PVDF) composites were controlled by the self-assembly of the BT secondary particle groups. The self-assembled BT/PVDF composites of 520 vol.% BT were prepared with the difference in the viscosity of polyethylene glycol (PEG) of dispersants involved in the self-assembly process. The multifractal properties and dielectric properties of the self-assembled BT/PVDF composites were investigated with controlling by the formation of the self-assembled BT secondary particle groups. The dielectric constant (¾¤) increased with an increase in the average secondary particle area (S) of the BT particles. The S increased with an increase in the viscosity of PEG; whereas, the ¾¤ decreased with the increase in viscosity. The multifractal analysis indicated that the distribution of self-assembled BT secondary particle groups was affected by PEG viscosity. The sample with PEG1000 had aggregates with a BT/PVDF/BT heterointerface, the sample with PEG20000 had agglomerates with a BT/BT interface, and the sample with PEG2000 had both, aggregates and agglomerates. The BT/PVDF/BT heterointerface in the BT aggregates played an important role in improving the dielectric properties of the BT/PVDF composites. Overall, the viscosity of the dispersant affected the self-assembly process as well as the ¾¤. It was suggested that the multifractal properties and dielectric properties were controlled by the self-assembly of the BT secondary particle groups.

Thermal conductivities and complex network properties of fractal self-assembled/self-organized texture in binary composite materials

“…This is similar to the agglomeration/aggregation and growth of fillers in a matrix. As previously reported for fractal material texture organization, [6][7][8][9][10][11][12][13][14][15] the construction of this self-assembly/self-organization consists of the following two processes:…”

“…In fact, from the results of this power distribution and the changes in the γ value, there are regions where the formation of particle groups is dominant (small particle groups) and regions where their growth is dominant (large particle groups). However, in the BT/PVDF system, once a particle group is formed, the interaction between the particle groups is suppressed [8,9], and the system does not exhibit a power distribution or normal distribution in the region where s is large.…”

“…In particular, the interaction of the filler particles in the matrix and the resulting network formation are important for expressing specific functionality. In fact, in β-Si 3 N 4 (SN)/austenitic stainless steel (SUS) [6,7] and BaTiO 3 (BT)/piezoelectric polyvinylidene fluoride (PVDF) [8][9][10][11][12][13][14][15] systems, the characteristics of the material structure constructed by the process of self-assembly or self-organization have been mapped to material performance such as dielectric properties and thermal conductivity.…”

“…On the other hand, multifractal analysis [1-5], which is widely used in physics, chemistry, medicine, and engineering involving morphology and shape, is being applied to the field of materials science. Recently, this analysis has been used to reveal the particle morphology, arrangement, dispersion, and statistical thermodynamic properties during chemical reaction processes, and has been shown to be effective in clarifying the dissipation state of particles due to self-organized or self-assembled processes in real binary systems (metal/ceramics and polymer/ceramics) [6][7][8][9][10]. In particular, the general dimension D q (multiple fractal dimension for q-th order moment) and scaling exponent τ q obtained from the microstructural morphologies of self-organized or self-assembled materials serve as material design indices for designing composite materials with Fumio Munakata…”