title: Directed Self-Assembly of Block Copolymers for High Breakdown Strength Polymer Film Capacitors.
abstract: Emerging needs for fast charge/discharge yet high-power, lightweight, and flexible electronics requires the use of polymer-film-based solid-state capacitors with high energy densities. Fast charge/discharge rates of film capacitors on the order of microseconds are not achievable with slower charging conventional batteries, supercapacitors and related hybrid technologies. However, the current energy densities of polymer film capacitors fall short of rising demand, and could be significantly enhanced by increasing the breakdown strength (EBD) and dielectric permittivity (εr) of the polymer films. Co-extruded two-homopolymer component multilayered films have demonstrated much promise in this regard showing higher EBD over that of component polymers. Multilayered films can also help incorporate functional features besides energy storage, such as enhanced optical, mechanical, thermal and barrier properties. In this work, we report accomplishing multilayer, multicomponent block copolymer dielectric films (BCDF) with soft-shear driven highly oriented self-assembled lamellar diblock copolymers (BCP) as a novel application of this important class of self-assembling materials. Results of a model PS-b-PMMA system show ∼50% enhancement in EBD of self-assembled multilayer lamellar BCP films compared to unordered as-cast films, indicating that the breakdown is highly sensitive to the nanostructure of the BCP. The enhancement in EBD is attributed to the "barrier effect", where the multiple interfaces between the lamellae block components act as barriers to the dielectric breakdown through the film. The increase in EBD corresponds to more than doubling the energy storage capacity using a straightforward directed self-assembly strategy. This approach opens a new nanomaterial paradigm for designing high energy density dielectric materials.
authors.affiliation: Department of Polymer Engineering, University of Akron , Akron, Ohio 44325, United States.
authors.forename: Saumil P
authors.initials: SP
authors.lastname: Samant
authors.affiliation: Air Force Research Laboratory, Wright Patterson Air Force Base , Dayton, Ohio 45433, United States.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Grabowski
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States.
authors.forename: Kim
authors.initials: K
authors.lastname: Kisslinger
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States.
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Yager
authors.affiliation: Center for Neutron Research, National Institute of Standards and Technology (NIST) , Gaithersburg, Maryland 20899, United States.
authors.forename: Guangcui
authors.initials: G
authors.lastname: Yuan
authors.affiliation: Center for Neutron Research, National Institute of Standards and Technology (NIST) , Gaithersburg, Maryland 20899, United States.
authors.forename: Sushil K
authors.initials: SK
authors.lastname: Satija
authors.affiliation: Air Force Research Laboratory, Wright Patterson Air Force Base , Dayton, Ohio 45433, United States.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Durstock
authors.affiliation: Department of Chemistry, Howard University , Washington, D.C. 20059, United States.
authors.forename: Dharmaraj
authors.initials: D
authors.lastname: Raghavan
authors.affiliation: Department of Polymer Engineering, University of Akron , Akron, Ohio 44325, United States.
authors.forename: Alamgir
authors.initials: A
authors.lastname: Karim
keywords: barrier effect; block copolymer; breakdown strength; capacitor; cold zone annealing−soft shear; dielectric; directed self-assembly; lamellae