Y. Jin, R.A. Gerhardt
Georgia Institute of Technology, United States
pp. 157 - 160
Keywords: polymer matrix composites (PMCs), dielectric composite, functional composite, dielectric properties
Poly(vinylidene fluoride)(PVDF) matrix hybrid nanocomposites featuring ferroelectric barium titanate nanoparticles and multi-walled carbon nanotubes(MWCNT) embedded in the polymer were fabricated by miscible-immiscible coagulation method followed by hot pressing . The SEM images showed good distribution of ferroelectric nanoparticles with very little particle agglomeration. The conductive MWCNT increased the charge storage ability of the matrix polymer by serving as a charge transport phase for the ferroelectric nanoparticles, resulting in high real permittivity and low dielectric loss over a wide range of frequency (10 Hz to 1 MHz). At a BaTiO3 content of 22.8 vol %, real permittivity was increased from 26.9 to 52.68 at 1 kHz with 4 vol % of MWCNT and there was no noticeable increase in dielectric loss (0.049 to 0.055 at 1 kHz). Dielectric properties of the polymer matrix hybrid nanocomposites were further improved using a MWCNT content near the electrical percolation with consequent optimum synergistic effects between the charge storage effects of the ferroelectric phase and the charge transport effects of the conductive phase . The real permittivity was 71.7 and the dielectric loss was 0.046 at 1 kHz for composites containing 37.2 vol % of BaTiO3 and 3 vol % of MWCNT. Due to the simplicity of the processing method, reliable dielectric properties and flexibility, this composite may be useful in many electronic applications such as high energy density capacitors and flexible high-k dielectrics such as embedded dielectric components in the organic printed circuit board .