title: Fabrication of Stretchable Nanocomposites with High Energy Density and Low Loss from Cross-Linked PVDF Filled with Poly(dopamine) Encapsulated BaTiO3.
abstract: In this report, a simple solution-cast method was employed to prepare poly(dopamine) (PDA) encapsulated BaTiO3(BT) nanoparticle (PDA@BT) filled composites using PVDF matrix cross-linked by the free radical initiator. The effects of both the particle encapsulation and matrix cross-linking on the mechanical and dielectric properties of the composites were carefully investigated. The results suggested that the introduction of BT particles improved permittivity of the composites to ∼30 at 100 Hz when particle contents of only 7 wt % were utilized. This was attributed to the enhanced polarization, which was induced by high permittivity ceramic particles. Compared to bare BT, PDA@BT particles could be dispersed more homogeneously in the matrix, and the catechol groups of PDA layer might form chelation with free ions present in the matrix. The latter might depress the ion conduction loss in the composites. Other results revealed that the formation of hydrogen-bonding between the PDA layer and the polymer, especially the chemical cross-linking across the matrix, resulted in increased Young' modulus by ∼25%, improved breakdown strength by ∼40%, and declined conductivity by nearly 1 order of magnitude when compared to BT filled composites. The composite films filled with PDA@BTs indicated greater energy storage capacities by nearly 190% when compared to the pristine matrix. More importantly, the excellent mechanical performance allowed the composite films to adopt uni- or biaxially stretching, a crucial feature required for the realization of high breakdown strength. This work provided a facile strategy for fabrication of flexible and stretchable dielectric composites with depressed dielectric loss and enhanced energy storage capacity at low filler loadings (<10 wt %).
authors.affiliation: Department of Materials Chemistry, School of Science, Xi'an Jiaotong University , Xi'an 710049, P. R. China.
authors.forename: Yunchuan
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Materials Chemistry, School of Science, Xi'an Jiaotong University , Xi'an 710049, P. R. China.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Applied Chemistry, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi'an Jiaotong University , Xi'an 710049, P. R. China.
authors.forename: Yefeng
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Materials Chemistry, School of Science, Xi'an Jiaotong University , Xi'an 710049, P. R. China.
authors.forename: Wanrong
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Department of Applied Chemistry, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi'an Jiaotong University , Xi'an 710049, P. R. China.
authors.forename: Zhicheng
authors.identifier: http://orcid.org/0000-0003-0202-384X
authors.initials: Z
authors.lastname: Zhang
keywords: breakdown strength; chemical cross-linking; dielectric loss; energy storage capacity; poly(dopamine); stretchable; surface modification