Structured block copolymer thin film composites for ultra-high energy density capacitors

Development of high energy density capacitors is essential for future applications like hybrid vehicles and directed energy weaponry. Fundamentally, energy density is governed by product of dielectric permittivity $\varepsilon $ and breakdown strength V$_{bd}$. Hence, improvements in energy density are greatly reliant on improving either $\varepsilon $ or V$_{bd}$ or a combination of both. Polymer films are widely used in capacitors due to high Vbd and low loss but they suffer from very low permittivities. Composite dielectrics offer a unique opportunity to combine the high $\varepsilon $ of inorganic fillers with the high V$_{bd}$ of a polymer matrix. For enhancement of dielectric properties, it is essential to improve matrix-filler interaction and control the spatial distribution of fillers for which nanostructured block copolymers BCP act as ideal templates. We use Directed Self-assembly of block copolymers to rapidly fabricate highly aligned BCP-TiO2 composite nanostructures in thin films under dynamic thermal gradient field to synergistically combine the high $\varepsilon $ of functionalized TiO2 and high V$_{bd}$ of BCP matrix. The results of impact of BCP morphology, processing conditions and concentration of TiO2 on capacitor performance will be reported.