1. Simultaneous Block Copolymer and Magnetic Nanoparticle Assembly in Nanocomposite Films
- Author
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James M. Kikkawa, Chen Xu, Vincent Ladmiral, Daniel E. Milkie, Russell J. Composto, and Kohji Ohno
- Subjects
Nanocomposite ,Morphology (linguistics) ,Materials science ,Polymers and Plastics ,Organic Chemistry ,Nanoparticle ,Methacrylate ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,Materials Chemistry ,Copolymer ,Lamellar structure ,Superparamagnetism ,Magnetite - Abstract
We investigate self-assembly of nanocomposite films composed of lamellar-forming poly(styrene-b-methyl methacrylate) (PS-b-PMMA) and PMMA-grafted magnetite (Fe3O4) nanoparticles (NPs). The Fe3O4 NPs are grafted with PMMA brushes with molecular weights ranging from 2700 to 35 700 g/mol. For the NP with the lowest molecular weight brush, the morphology of the nanocomposite film depends on the NP concentration (ϕNP). At low ϕNP, the block copolymer self-assembles into mixed morphology of perpendicular lamellae (⊥Lam) and parallel lamellae (∥Lam), and the ⊥Lam are stabilized by individual NPs or small NP aggregates. The NPs can also retard the dynamics of self-assembly of block copolymer films. At high ϕNP, NPs form small aggregates which inhibit the formation of a lamellar structure. As the molecular weight of the PMMA brush increases to 13 300 or 35 700 g/mol, the Fe3O4 NPs form aggregates in the as-cast nanocomposite films, and this behavior is attributed to aggregation of NPs in the solution state. Since ...
- Published
- 2009