Effects of nanoparticles size and interactions on dielectric properties of polymer matrix flexible dielectric nanocomposites

Abstract

Effects of particle size on the dielectric properties of polymer matrix flexible nanocomposites were studied. Synthesized barium titanate (BaTiO₃; BT) nanoparticles (NPs) with different sizes were effectively dispersed in the matrix polymer using a simple phase separation method. The dielectric responses of free-standing thin composite films were studied by impedance spectroscopy. The interactions between nanoparticles were also studied by finite element analysis and compared with experimental data using a time harmonic-electric current solver in the AC/DC module of COMSOL Multiphysics® 5.2. The dielectric permittivity of polymer matrix nanocomposites was remarkably affected by the BT particle size, while the dielectric loss did not show any noticeable changes. The real permittivity exhibited the highest value when the BT particle size was near 100 nm. The calculated energy density based on measured real permittivity and breakdown strength was as high as 17.24 J/cm³. The dielectric properties of polymer matrix nanocomposites can be improved by controlling the particle size of nanofillers in conjunction with surface treatment of fillers.

Keywords:

• dielectric composite
• polymer composite
• nanocomposite
• flexible composite
• dielectric constant
• energy density
• high permittivity
• impedance spectroscopy
• COMSOL

Acknowledgements

Research funding from the US National Science Foundation (NSF) under DMR-1207323 and additional funding from Agency for Defense Development under 912693101 are acknowledged and appreciated.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Science Foundation [DMR-2351207323; Agency for Defense Development [912693101].