title: Confined crystallization of polyethylene oxide in nanolayer assemblies.
abstract: The design and fabrication of ultrathin polymer layers are of increasing importance because of the rapid development of nanoscience and nanotechnology. Confined, two-dimensional crystallization of polymers presents challenges and opportunities due to the long-chain, covalently bonded nature of the macromolecule. Using an innovative layer-multiplying coextrusion process to obtain assemblies with thousands of polymer nanolayers, we discovered a morphology that emerges as confined polyethylene oxide (PEO) layers are made progressively thinner. When the thickness is confined to 20 nanometers, the PEO crystallizes as single, high-aspect-ratio lamellae that resemble single crystals. Unexpectedly, the crystallization habit imparts two orders of magnitude reduction in the gas permeability.
authors.affiliation: Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106-7202, USA.
authors.forename: Haopeng
authors.initials: H
authors.lastname: Wang
authors.forename: Jong K
authors.initials: JK
authors.lastname: Keum
authors.forename: Anne
authors.initials: A
authors.lastname: Hiltner
authors.forename: Eric
authors.initials: E
authors.lastname: Baer
authors.forename: Benny
authors.initials: B
authors.lastname: Freeman
authors.forename: Artur
authors.initials: A
authors.lastname: Rozanski
authors.forename: Andrzej
authors.initials: A
authors.lastname: Galeski