title: Block copolymer/ferroelectric nanoparticle nanocomposites.
abstract: Nanocomposites composed of diblock copolymer/ferroelectric nanoparticles were formed by selectively constraining ferroelectric nanoparticles (NPs) within diblock copolymer nanodomains via judicious surface modification of ferroelectric NPs. Ferroelectric barium titanate (BaTiO3) NPs with different sizes that are permanently capped with polystyrene chains (i.e., PS-functionalized BaTiO3NPs) were first synthesized by exploiting amphiphilic unimolecular star-like poly(acrylic acid)-block-polystyrene (PAA-b-PS) diblock copolymers as nanoreactors. Subsequently, PS-functionalized BaTiO3 NPs were preferentially sequestered within PS nanocylinders in the linear cylinder-forming polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer upon mixing the BaTiO3 NPs with PS-b-PMMA. The use of PS-b-PMMA diblock copolymers, rather than traditional homopolymers, offers the opportunity for controlling the spatial organization of PS-functionalized BaTiO3 NPs in the PS-b-PMMA/BaTiO3 NP nanocomposites. Selective solvent vapor annealing was utilized to control the nanodomain orientation in the nanocomposites. Vertically oriented PS nanocylinders containing PS-functionalized BaTiO3 NPs were yielded after exposing the PS-b-PMMA/BaTiO3 NP nanocomposite thin film to acetone vapor, which is a selective solvent for PMMA block. The dielectric properties of nanocomposites in the microwave frequency range were investigated. The molecular weight of PS-b-PMMA and the size of BaTiO3 NPs were found to exert an apparent influence on the dielectric properties of the resulting nanocomposites.
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Xinchang
authors.initials: X
authors.lastname: Pang
authors.forename: Yanjie
authors.initials: Y
authors.lastname: He
authors.forename: Beibei
authors.initials: B
authors.lastname: Jiang
authors.forename: James
authors.initials: J
authors.lastname: Iocozzia
authors.forename: Lei
authors.initials: L
authors.lastname: Zhao
authors.forename: Hanzheng
authors.initials: H
authors.lastname: Guo
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.forename: Mufit
authors.initials: M
authors.lastname: Akinc
authors.forename: Nicola
authors.initials: N
authors.lastname: Bowler
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Tan
authors.forename: Zhiqun
authors.initials: Z
authors.lastname: Lin