Regulating dielectric performances of Poly(vinylidene fluoride) nanocomposites by individually controlling shell thickness of Core@Double‐Shells structured nanowires

Abstract

The synthesis of core@double‐shells structured TiO2@C@SiO2 nanowires (NWs) with variable thickness of carbon inner shell and SiO2 outer shell was achieved by individually controlling the chemical vapour deposition time and amount of silicon precursor added in the sol–gel synthesis. The resultant TiO2@C@SiO2 NWs filled nanocomposites exhibited an excellent dielectric performance with simultaneously improved dielectric constant and suppressed dielectric loss, which could be further regulated by individually controlling the carbon inner shell and SiO2 outer shell thickness. More importantly, the influences of the conductive carbon inner shell and insulated SiO2 outer shell thickness on the dielectric performance of nanocomposites were clearly revealed. The increase of the conductive carbon inner shell thickness would lead to an increase in dielectric constant and loss of nanocomposites, while the insulated SiO2 outer shell exhibited a totally opposite law that the dielectric constant and loss of nanocomposites decrease with increasing SiO2 outer shell thickness. Numerical simulations were also carried out to theoretically verify the relationship between the dielectric loss and SiO2 outer shell thickness. This promising controllable multi‐shell structure could be extended to a variety of hybrids to develop high‐performance dielectric nanocomposites.

BaTiO3 Nanoparticles Coated with Polyurethane and SiO2 for Enhanced Dielectric Properties

“…In addition, SiO 2 exhibits a higher band gap (8.9 eV) than other inorganic layers, therefore facilitating the decrease of the electric losses in nanocomposites. 26,27 Moreover, the dielectric constant of SiO 2 is similar to the intrinsic polymers. It is conducive to alleviating the huge electric field distortion at the filler−polymer interface, thereby improving the breakdown strength of polymers.…”

“…Currently, many polymers such as polydopamine (PDA), methyl methacrylate (PMMA), and polyaniline (PANI) are widely used as organic shells. − Different from the above polymers, polyurethane (PU) is a linearly segmented block polymer in which the soft segment is changeable and controllable. , Thereby, PU is a suitable shell for detailed studies of the effect of flexible polymers on dielectric properties. In addition, SiO 2 exhibits a higher band gap (8.9 eV) than other inorganic layers, therefore facilitating the decrease of the electric losses in nanocomposites. , Moreover, the dielectric constant of SiO 2 is similar to the intrinsic polymers. It is conducive to alleviating the huge electric field distortion at the filler–polymer interface, thereby improving the breakdown strength of polymers .…”

Improved Energy Storage Performance in Sandwiched Poly(vinylidene fluoride)-Based Composites Assembling with In-Plane-Oriented BN Nanosheets and TiO2 Nanowires

“…Based on this abovementioned consideration, the nanocomposites consisting of inorganic nanofillers with high-ε r and a polymer matrix with high- E b hold great promise for the fabrication of modern electrical devices with excellent energy storage capabilities. Although the traditional approach of randomly mixing high-ε r zero-dimensional (0D) nanoparticles with polymer matrices to fabricate ε r -regulated composites has been extensively reported previously, the extremely large loading of nanofiller also brings with it the problems of decayed processability and premature breakdown in composites. − Therefore, it is crucial to seek suitable strategies to resolve the significant negative coupling effect between ε r and E b in composite dielectrics …”