Surface-initiated polymerization from barium titanate nanoparticles for hybrid dielectric capacitors.
A phosphonic acid is used as a surface initiator for the growth of polystyrene and polymethylmethacrylate (PMMA) from barium titanate (BTO) nanoparticles through atom transfer radical polymerization with activators regenerated by electron transfer. This results in the barium titanate cores embedded in the grafted polymer. The one-component system, PMMA-grafted-BTO, achieves a maximum extractable energy density of 2 J/cm(3) at a field strength of ∼220 V/μm, which exhibits a 2-fold increase compared to that of the composite without covalent attachment or the neat polymer. Such materials have potential applications in hybrid capacitors due to the high permittivity of the nanoparticles and the high breakdown strength, mechanical flexibility, and ease of processability due to the organic polymer. The synthesis, processing, characterization, and testing of the materials in capacitors are discussed.
School of Chemistry and Biochemistry, ‡School of Materials Science and Engineering, and §School of Chemical and Biomolecular Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
Sergio A
SA
Paniagua
Yunsang
Y
Kim
Katherine
K
Henry
Ritesh
R
Kumar
Joseph W
JW
Perry
Seth R
SR
Marder