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: Processing and gas barrier behavior of multilayer thin nanocomposite films
  name:
    name part: Yang, You-Hao.
    role:
      role term: creator
  name:
    name part: Grunlan, Jaime C.
    role:
      role term: thesis advisor.
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: txu
    date issued: 2012
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: remote
    extent: 1 online resource.
  abstract: Thin films with the ability to impart oxygen and other types of gas barrier are crucial to commercial packaging applications. Commodity polymers, such as polyethylene (PE), polycarbonate (PC) and polyethylene terephthalate (PET), have insufficient barrier for goods requiring long shelf life. Current gas barrier technologies like plasma-enhanced vapor deposition (PECVD) often create high barrier metal oxide films, which are prone to cracking when flexed. Bulk composites composed of polymer and impermeable nanoparticles show improved barrier, but particle aggregation limits their practical utility for applications requiring high barrier and transparency. Layer-by-layer (LbL) assemblies allow polymers and nanoparticles to be mixed with high particle loadings, creating super gas barrier thin films on substrates normally exhibiting high gas permeability. Branched polyethylenimine (PEI) and poly (acrylic acid) (PAA) were deposited using LbL to create gas barrier films with varying pH combinations. Film thickness and mass fraction of each component was controlled by their combined charge. With lower charge density (PEI at pH 10 and PAA at pH 4), PEI/PAA assemblies exhibit the best oxygen barrier relative to other pH combinations. An 8 BL PEI/PAA film, with a thickness of 451 nm, has an oxygen permeability lower than 4.8 x 10^-21 cm^3 * cm/cm^2 * s * Pa, which is comparable to a 100 nm SiOx nanocoating. Crosslinking these films with glutaraldehyde (GA), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide methiodide (EDC) or heating forms covalent bonds between PEI and/or PAA. Oxygen transmission rates (OTR) of 8 BL films crosslinked with 0.1M GA or 0.01M EDC show the best oxygen barrier at 100% RH. Graphene oxide (GO) sheets and PEI were deposited via LbL with varying GO concentration. The resulting thin films have an average bilayer thickness from 4.3 to 5.0 nm and a GO mass fraction from 88 to 91wt%. Transmission electron microscopy and atomic force microscopy images reveal a…
  note: by You-Hao Yang.
  note: "Major Subject: Chemical Engineering"
  note: Electronic resource.
  note: Doctor of Philosophy Texas A&M University 2012 http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11685
  note: Includes bibliographical references.
  note: Text (Dissertation)
  subject:
    topic: Major Chemical Engineering
  subject:
    topic: Layer-by-layer
  subject:
    topic: graphene oxide
  subject:
    topic: moisture barrier
  subject:
    topic: crosslink
  subject:
    topic: polyelectrolyte
  subject:
    topic: gas barrier
  identifier: http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11685
  record info:
    record content source: TXA
    record creation date: 121126
    record change date: 20150922145619.0
    record identifier: in00002785468