Influence of nanoscale surface topographical heterogeneity on colloidal interactions

• Author / Creator

  Hosseini, Amir

• In this thesis, measurement and analysis of colloidal forces between an atomic force microscope (AFM) probe and a topographically patterned substrate are reported. The energy between the patterned substrate and a smooth flat plate was characterized mathematically using Surface Element Integration (SEI) method. Hemispherical, conical, and cylindrical shape asperities in form of either protrusions or depressions were arrayed on a square lattice to model the rough surface. The variation of DLVO interaction energies on such nano-patterned surfaces was investigated as a function of the size and density of the asperities. It was demonstrated that roughness elements attenuate the near-field DLVO energy by orders of magnitude, whereas at larger separations, their effect is insignificant. The interaction of an AFM hemispherical model probe and a rough surface was also calculated when the probe laterally moves over the surface. The resulting energy distribution maps reveal how the AFM experimental force-distance measurements can vary depending on the lateral position of the probe on the patterned substrate.

• Subjects / Keywords

  • Nano
  • Interactions
  • Atomic force
  • Microscopy
  • Surfaces
  • AFM
  • Colloidal forces

• Graduation date

  Spring 2011

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3MP8C

• 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.