Usage
  • 51 views
  • 469 downloads

Nanoengineered Glancing Angle Deposition Thin Films for Ultrathin-Layer Chromatography

  • Author / Creator
    Jim, Steven R.
  • Analytical separations are important methods of identifying and quantifying molecular compounds present in complex sample mixtures. These approaches are popular in biochemistry, medical diagnostics, quality control, and numerous other applications. In these techniques, constituent analytes are separated according to their characteristic physical and chemical properties. Planar chromatography analytical separations leverage the effects of these properties on competing interactions between the compounds, moving liquids, and stationary flat porous solids. Engineered solid-liquid interfaces can improve performance since these interactions occur at the nanoscale. Ultrathin-layer chromatography (UTLC) is a miniature form of planar chromatography in which sample analytes are carried by solvents that wick through < 10 um thick solids with extraordinarily fine pores. The technique achieves fast separations (minutes) over short distances (millimetres to centimetres) with high sensitivity. The strong dependence of UTLC performance on layer microstructure motivates pursuit of new chromatographic media. This dissertation studies UTLC layers produced using glancing angle deposition (GLAD). GLAD is an excellent platform for engineering nanostructured thin films of varied material, porosity, and architecture. It can achieve ~ 5 um thick columnar morphologies well-suited for UTLC that are unattainable or impractical using other techniques. Unique anisotropic media exhibited channel features that strongly influenced analyte migration direction and velocity. Further control of chromatographic behaviours was achieved using post-deposition enhancements. Fluorocarbon reactive ion etching (RIE) selectively modifies film microstructure, increases porosity, and decreases the surface area over which analytes may interact. Atomic layer deposition (ALD) applies extremely thin < 10 nm conformal coatings that produce alternative chromatographic surface chemistries over GLAD UTLC film scaffolds. These investigations required invention of new instrumentation and analysis techniques since conventional planar chromatography equipment is unoptimized for miniaturized GLAD UTLC plates. Approaches to fabricating, utilizing, characterizing, and enhancing nanoengineered GLAD UTLC media are considered in this thesis. The intriguing behaviours described within provide insight into the manner in which the microscopic features of GLAD films impact macroscopic development phenomena. These investigations simultaneously advanced both the capabilities of the UTLC planar chromatography technique and the understanding of GLAD nanostructured thin film materials.

  • Subjects / Keywords
  • Graduation date
    2014-06
  • Type of Item
    Thesis
  • Degree
    Doctor of Philosophy
  • DOI
    https://doi.org/10.7939/R30R9MC26
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Doctoral
  • Department
    • Department of Electrical and Computer Engineering
  • Specialization
    • Microsystems and Nanodevices
  • Supervisor / co-supervisor and their department(s)
    • Brett, Michael (Electrical and Computer Engineering)
  • Examining committee members and their departments
    • Poole, Colin (Chemistry, Wayne State University, Detroit, MI, USA)
    • Thundat, Thomas (Chemical and Materials Engineering)
    • Brett, Michael (Electrical and Computer Engineering)
    • Cadien, Kenneth (Chemical and Materials Engineering)
    • Zemp, Roger (Electrical and Computer Engineering)