The field of polymer nanocomposites has been at the forefront of research in the polymer community for the past few decades. Foundational work published in Macromolecules during this time has emphasized the physics and chemistry of the inclusion of nanofillers; remarkable early developments suggested that these materials would create a revolution in the plastics industry. After 25 years of innovative and groundbreaking research, PNCs have enabled many niche solutions. To complement the extensive literature currently available, we focus this Perspective on four case studies of PNCs applications: (i) filled rubbers, (ii) continuous fiber reinforced thermoset composites, (iii) membranes for gas separations, and (iv) dielectrics for capacitors and insulation. After presenting synthetic developments we discuss the application of polymer nanocomposites to each of these topic areas; successes will be noted, and we will finish each section by highlighting the various technological bottlenecks that need to be over...

50th Anniversary Perspective: Are Polymer Nanocomposites Practical for Applications?

Polymer/inorganic particle nanocomposites (or nanodielectrics) have attracted pronounced attention for electric energy storage applications, based on a hypothesis that polymer nanodielectrics could combine the high permittivity of nanoparticles and the high electrical breakdown strength of the polymer matrix for enhanced dielectric performance. Although higher discharged energy densities have been reported for numerous polymer nanodielectrics, the dielectric loss mechanisms, which are extremely important for ultimate applications, are rarely discussed. In this work, we intend to address the intrinsic dielectric loss mechanisms associated with polymer nanodielectrics using a model system comprised of 70 nm BaTiO3 nanoparticles (BT NPs) in an isotactic polypropylene (PP) matrix. The effect of space charge-induced interfacial polarization on dielectric losses was investigated using bipolar and unipolar electric displacement–electric field (D-E) loop tests. Since the bipolar D-E loops always exhibited greater...

Interfacial Polarization-Induced Loss Mechanisms in Polypropylene/BaTiO3 Nanocomposite Dielectrics

Ceramic/polymer nanocomposites are attractive for energy storage applications due to their ability to exploit the high permittivity of ceramic fillers and high breakdown strength of the polymer matrix. One challenge for the development of high performance nanocomposites based on ceramic particulates or fibers in a polymer matrix is that they often require a high volume fraction (>50%) to achieve a high permittivity, which is often at the expense of a reduction in dielectric strength and mechanical flexibility. In this paper we demonstrate by both experiment and finite element simulation that high aspect ratio nanofiber fillers offer an effective approach to achieve high energy density and dielectric strength. Lead-free ferroelectric Na0.5Bi0.5TiO3 (BNT) nanofibers with a high aspect ratio (>200) are synthesized by a hydrothermal method and dispersed in a poly(vinylidene difluoride-co-hexafluoropropylene) (P(VDF-HFP)) matrix. The increased fraction of β-phase and the alignment of BNT nanofibers perpendicular to the direction of the applied electric field lead to an enhanced dielectric strength, compared to spherical BNT/P(VDF-FHP) nanoparticles and pure P(VDF-HFP), and experimental measurements are compared with numerical simulations. The results demonstrate that the nanofiber nanocomposites exhibited an ultra-high discharged energy density (12.7 J cm−3) and provide an innovative approach to produce high-energy storage density materials.

/pdf/ultra-high-discharged-energy-density-capacitor-using-high-38xjmvz3sa.pdf

Ultra-high discharged energy density capacitor using high aspect ratio Na0.5Bi0.5TiO3 nanofibers

Polymer-based materials for achieving high energy density film capacitors

Polymer/SiO2 nanocomposites: Production and applications

The ultimate energy storage performance of an electrostatic capacitor is determined by the dielectric characteristics of the material separating its conductive electrodes. Polymers are commonly employed due to their processability and high breakdown strength; however, demands for higher energy storage have encouraged investigations of ceramic–polymer composites. Maintaining dielectric strength, and thus minimizing flaw size and heterogeneities, has focused development toward nanocomposite (NC) films; but results lack consistency, potentially due to variations in polymer purity, nanoparticle surface treatments, nanoparticle size, and film morphology. To experimentally establish the dominant factors in broad structure–performance relationships, we compare the dielectric properties for four high-purity amorphous polymer films (polymethyl methacrylate, polystyrene, polyimide, and poly-4-vinylpyridine) incorporating uniformly dispersed silica colloids (up to 45% v/v). Factors known to contribute to premature b...

Nicholas M. Westing

Papers

Dielectric breakdown in silica-amorphous polymer nanocomposite films: the role of the polymer matrix.