Dependence of the Interfacial Adhesion between Two Different Types of Material on their Electron Work Function and Electrical Conductivity

  • Author / Creator
    Setiawan, Raymond Christopher
  • We observed and investigated a novel interfacial phenomenon related to the dependence of interfacial bonding or adhesive force (Fad) between two substances on the difference in their Electron Work Functions (EWF) or Δφ, and developed a model to quantify such a dependence. First, using PEDOT:PSS/PEO nanofilm as a sample system with various wt./wt.% ratios of DMSO, we observed the dependence of its interfacial adhesion with Si3N4 (silicon nitride) on the nanofilm’s conductivity and Δφ of the system, determined through AFM analysis. It is shown that a larger Δφ and higher conductivity of the polymeric nanofilm increase its adhesive force with silicon nitride. The second series of experiments using a similar method were performed for different pure metals with the objective to develop a theoretical approach in elucidating the quantitative correlation between Fad and Δφ across the interface. This study demonstrates that the interfacial adhesive force is mainly governed by two factors: 1) the difference in EWF between the two materials in contact and 2) the electrical conductivity of the materials involved. The former acts as the driving force for establishing a double dipole layer at the interface, leading to the electrostatic interaction, while the latter determines the easiness of the system to form the double dipole layers. This study demonstrates an approach to tailor interfacial bonding for different material types without atomic diffusion, promising for applications in various fields, e.g., better control of biomedical films on implants and functional films for electronic devices. In the succeeding part, we established an analytical model to quantify the adhesive force (FAd) dependence between two different substances on their Electron Work Functions (EWF or φ) and conductivity without atomic diffusion involved. This model does not only help calculating the adhesive force but also elucidate the underlying mechanism.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • 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.