Morphology-induced dielectric enhancement in polymer nanocomposites. Issue 24 (16th June 2021)

• Record Type: Journal Article
• Authors: Zhang, Bing; Chen, Xin; Lu, Wenchang; Zhang, Q. M.; Bernholc, J.
• Is Part Of: Nanoscale. Volume 13:Issue 24(2021)
• Page Start: 10933
• Page End: 10942
• Publication Date: 2021-06-16
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d1nr00165e
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Admixture of dilute nanoparticles into dipolar polymer dielectrics enlarges free volume and increases permittivity by over 50%. Abstract : The mechanism of the recently discovered enhancement of dielectric properties in dilute polymer-nanoparticle composites is investigated by experiments and computer simulations. We show that the weakening of the hydrogen bonds between the nanoparticles and the polymer chains reduces the polymer-nanoparticle composite's dielectric enhancement. The subsequent multiscale simulations investigate the attachment of solvated highly dipolar polymers to oxide nanoparticles, which leads to deposition of nanoparticle–polymer blobs during solution casting and a reduced density compared to a neat polymer film. Coarse-grained simulations of nanocomposite morphology are followed by molecular dynamics and density functional theory calculations of permittivities. The increased free volume in the nanocomposite enables easier reorientation of monomer dipoles with an applied electric field, and thus a higher dielectric permittivity. The numerical results are in excellent agreement with experimental data for PEEU and PEI nanocomposites.