Development of high energy density capacitors with fast discharge rates is essential to reduce the size, weight and cost of devices in future applications like hybrid vehicles and directed energy. Fundamentally, the dielectric material limits capacitor performance, with the energy density governed by the product of dielectric permittivity e and breakdown strength Vbd. Therefore, further improvements in capacitor energy density are greatly reliant on improving either e or Vbd, or finding improvements through a combination of enhancement of both properties. Polymer films are widely used as the dielectric medium in capacitors due to high breakdown strength, good processibility, low loss and fast discharge speeds. However, they suffer from very low permittivities in this regard. Composite dielectrics offer the unique opportunity to combine the high permittivity of inorganic filler materials with the high breakdown strength of an organic polymer host material. For optimum enhancement of dielectric properties, it is essential to improve matrix-filler interaction and control the dispersion and spatial distribution of the fillers. Nanostructured block copolymers (BCP) act as ideal templates to selectively sequester and organize nano-fillers within polymer matrices. We use Directed Self-assembly (DSA) of block copolymers to rapidly fabricate highly aligned BCP nanostructures with functionalized high-permittivity TiO2 in thin films (500nm-1�m) under dynamic thermal gradient fields to synergistically combine the high permittivity of TiO2 and high breakdown of block copolymer matrix for high energy density capacitors. The results of impact of block copolymer morphology, processing conditions, nature of functionalization and concentration of TiO2 nanoparticles on the capacitor performance will be reported.

Structured block copolymer nanocomposite thin films for high density pulsed power capacitors

248th National Meeting (2014)

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