| Dielectric materials with large electric energy density are actively pursued for many applications. Among commercially available polymer capacitor film, poly(vinylidene fluoride chlorotrifluoroethylene) P(VDF-CTFE) stands out due to its excellent capability to store electrical energy with relatively high efficiency. In this dissertation, we employed crosslinking approaches to improve energy density of the copolymer by concurrently reducing loss, enhancing permittivity, and improving breakdown strength of the copolymer. The fundamental idea of this effort is to introduce covalent bonding between the polymer chains to confine and destabilize the formation of ferroelectric domain. By carefully controlling of the process conditions and varying the polymer/crosslinking agents feeding ratios the copolymer structures were systematically tuned for optimized dielectric and electrical properties. The crosslinking method leads to the copolymer film with impressive 64% decreased of total loss, 24% improvement of polarization level (under 250 MV/m field) and 70 % improvement of breakdown strength compared to the pristine. All of above improvements have been synergized and consequently 315 % enhancement of energy density can be achieved in the crosslinked copolymers. |
