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Structurally well-defined polymer-grafted nanoparticle hybrids are highly sought after for a variety of applications, such as antifouling, mechanical reinforcement, separations, and sensing. Herein, we report the synthesis of poly(methyl methacrylate) grafted- and poly(styrene) grafted-BaTiO3 nanoparticles using activator regeneration via electron transfer (ARGET ATRP) with a sacrificial initiator, atom transfer radical polymerization (normal ATRP), and ATRP with sacrificial initiator, to understand the role of the polymerization procedure in influencing the structure of nanoparticle hybrids. Irrespective of the polymerization procedure adopted for the synthesis of nanoparticle hybrids, we noticed PS grafted on the nanoparticles showed moderation in molecular weight and graft density (ranging from 30,400 to 83,900 g/mol and 0.122 to 0.067 chain/nm2) compared to PMMA-grafted nanoparticles (ranging from 44,620 to 230,000 g/mol and 0.071 to 0.015 chain/nm2). Reducing the polymerization time during ATRP has a significant impact on the molecular weight of polymer brushes grafted on the nanoparticles. PMMA-grafted nanoparticles synthesized using ATRP had lower graft density and considerably higher molecular weight compared to PS-grafted nanoparticles. However, the addition of a sacrificial initiator during ATRP resulted in moderation of the molecular weight and graft density of PMMA-grafted nanoparticles. The use of a sacrificial initiator along with ARGET offered the best control in achieving lower molecular weight and narrow dispersity for both PS (37,870 g/mol and PDI of 1.259) and PMMA (44,620 g/mol and PDI of 1.263) nanoparticle hybrid systems. [ABSTRACT FROM AUTHOR]

This review provides a detailed overview of the latest developments using nanoscale strategies in the field of polymeric and polymer nanocomposite materials for emerging dielectric capacitor-based energy storage applications. Among the various energy storage devices, solid-state dielectric capacitors possess the advantage of high-power density which makes them highly attractive for pulsed power applications. Polymers are particularly suitable for dielectric energy storage applications because of their high breakdown strength, low dielectric loss, formability, self-healing capability, flexibility, solvent processability, and graceful breakdown failure. Strategies to enhance the dielectric breakdown strength of polymeric dielectric capacitors are emphasized in this review. General background on breakdown mechanism, breakdown characteristics, and factors influencing polymer dielectrics breakdown are introduced. Given that polymers have low permittivity, strategies to substantially enhance dipole mobility and hence the permittivity, are highlighted. We discuss strategies to address permittivity contrast between nanofillers and the polymer matrix including the potential for developing gradient permittivity structured nanofillers. To improve the compatibility of nanofiller with polymer and minimize nanofiller aggregation, different routes to surface functionalize nanoparticles are presented. An outlook and future perspectives section are provided for the design of high energy density polymer film capacitors. [ABSTRACT FROM AUTHOR]