Recent Advances in the Synthesis of Polymer-Grafted Low-K and High-K Nanoparticles for Dielectric and Electronic Applications

Abstract

The synthesis of polymer-grafted nanoparticles (PGNPs) or hairy nanoparticles (HNPs) by tethering of polymer chains to the surface of nanoparticles is an important technique to obtain nanostructured hybrid materials that have been widely used in the formulation of advanced polymer nanocomposites. Ceramic-based polymer nanocomposites integrate key attributes of polymer and ceramic nanomaterial to improve the dielectric properties such as breakdown strength, energy density and dielectric loss. This review describes the ”grafting from” and ”grafting to” approaches commonly adopted to graft polymer chains on NPs pertaining to nano-dielectrics. The article also covers various surface initiated controlled radical polymerization techniques, along with templated approaches for grafting of polymer chains onto SiO2, TiO2, BaTiO3, and Al2O3 nanomaterials. As a look towards applications, an outlook on high-performance polymer nanocomposite capacitors for the design of high energy density pulsed power thin-film capacitors is also presented.

Polymer-Grafted Nanoparticles with Variable Grafting Densities for High Energy Density Polymeric Nanocomposite Dielectric Capacitors

“…In particular, dielectric capacitors have the highest power density among energy storage devices. Dielectric materials can be classified into ceramic dielectrics and polymer dielectrics. − Among various ceramic-based dielectric materials, barium titanate (BaTiO 3) is of unique importance owing to its high dielectric constant (ε r ). ,, However, BaTiO 3 -based dielectric materials typically have low dielectric strength and suffer from catastrophic failure, nonflexibility, etc . On the other hand, polymeric dielectrics such as poly­(methyl methacrylate) (PMMA) and polypropylene (PP) possess several advantages, including high dielectric breakdown strength, low dielectric loss, flexibility, formability, solvent processability, self-healing capability, and graceful breakdown failure over their inorganic counterparts .…”

A long chain-induced depletion effect for abnormal grafting in the preparation of bimodal bidisperse polymer-grafted nanoparticles

“…Therefore, it is particularly important to study how to increase the nanoparticles' dispersion in polymer substrates. 14,15 From a thermodynamic point of view, in order to increase the enthalpy compatibility of nanoparticles with polymer substrates, researchers have tried to modify small molecules on the surface of nanoparticles, or to synthesize nanoparticles in situ by sol-gel processing. By means of these improvements, although the dispersibility of nanoparticles in the polymer matrix has been greatly improved, the phenomenon of particle aggregation is still difficult to be completely suppressed.…”

Molecular Dynamics and Structure of Poly(Methyl Methacrylate) Chains Grafted from Barium Titanate Nanoparticles

“…A few strategies have been employed to prepare hybrid dielectrics with enhanced values of dielectric permittivity and low dielectric loss. Modification of the surface of the particles and the grafting density of the polymer chains by reversible deactivation radical polymerizations initiated from the surface of inorganic particles have been very efficient in controlling the microstructure of nanocomposites [ 7 , 8 , 9 , 10 , 11 , 12 ]. Reversible deactivation radical polymerizations, including atom transfer radical polymerization (ATRP), were used efficiently to synthesize well-defined core–shell systems with a polymer layer surrounding inorganic particles [ 13 , 14 , 15 , 16 ].…”