rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Gas Barrier and Separation Behavior of Layer-by-Layer Assemblies
  name:
    name part: Tzeng, Ping
    role:
      role term: creator
    role:
      role term: author.
  name:
    name part: Grunlan, Jaime
    role:
      role term: thesis advisor.
  name:
    name part: Texas A & M University
    role:
      role term: degree granting institution.
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: txu
    date issued: 2015
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: remote
    extent: 1 online resource.
  abstract: Thin films with the ability to control gas permeability are crucial to packaging and purification applications. The addition of impermeable nanoparticles into neat polymers improves barrier/separation properties by creating a tortuous pathway, but particle aggregation occurring at high filler loading can reduce transparency of these composites as well as barrier/separation improvement. Layer-by-layer (LbL) assembly allows full control of morphology at the nanoscale, so barrier/separation properties can be precisely controlled and the films remain flexible and transparent. A three component recipe, consisting of polyvinylamine, poly(acrylic acid) and montmorillonite clay was deposited as repeating PVAm/PAA/PVAm/MMT quadlayers (QL) via LbL assembly. By adjusting solution pH and varying the placement of polycation layers, polymer interdiffusion and clay concentration were controlled, as well as oxygen barrier. Another QL assembly, with a PEI/PAA/PEI/MMT repeating sequence, was deposited using LbL to create light gas barrier films. Transmission electron microscope images revealed a highly-oriented nanobrick wall structure. A 5 QL coating on 51 [micro]m polystyrene (PS) is shown to lower both hydrogen and helium permeability three orders of magnitude relative to bare PS, demonstrating better performance than ethylene vinyl-alcohol (EVOH) copolymer film and even metallized plastic. Graphene oxide sheets, along with chitosan and PAA were used in a CH/PAA/CH/GO QL assembly. pH deviation between CH and PAA ionizes the counter ion, creating a more interdiffused polymer matrix and resulting in higher GO loading. Thermal reduction of GO, provides improvement in barrier performance under humid conditions and better H₂/CO₂ separation behavior. Finally, a PEI/PAA multilayer membrane exceeding that of the current state-of-the-art gas separation membranes was performed. This ionically crosslinked assembly exhibits H₂/N₂ and selectivities beyond Robeson's upper-bound limit, which are…
  note: by Ping Tzeng.
  note: "Major Subject: Chemical Engineering"
  note: Includes vita.
  note: Doctor of Philosophy Texas A & M University 2015 http://hdl.handle.net/1969.1/155066
  note: Includes bibliographical references.
  note: Text (Dissertation)
  subject:
    topic: Major Chemical Engineering
  subject:
    topic: Layer-by-layer
  subject:
    topic: gas barrier
  subject:
    topic: gas separation
  subject:
    topic: nanobrick wall
  identifier: http://hdl.handle.net/1969.1/155066
  record info:
    record content source: TXA
    record creation date: 160303
    record change date: 20170928112053.0
    record identifier: in00003609513
    language of cataloging:
      language term: eng