Scanning probe microscopy investigations of (1) arrays of cysteine-coated CdS nanoparticles and (2) structures formed during the early stages of the corrosion of copper surfaces

Abstract

Scanning probe microscopy (SPM) characterizations are becoming more prevalent for surface investigations due to their capabilities for obtaining structural information and physical measurements. New capabilities of SPM for studying and controlling nanoscale processes are emerging as valuable assets in research. A fundamental understanding of the interactions of surface reactions provides essential information for developing workable applications for nanotechnology. Two applications of SPM are discussed in this dissertation. The first investigation uses atomic force microscopy (AFM) for the characterization of nanostructures produced with a newly developed lithographic technique called “two-particle” lithography. This new technique is based on particle lithography for the patterning of nanoparticles. Structural templates of either latex or silica guide the deposition of nanoparticles to generate 2D arrays of nanopatterns. The surface coverage, size and periodicity of the nanoparticle structures can be controlled by changing the particle size of the templating sphere. Particle lithography provides test platforms to enable multiple reproducible SPM measurements for nanostructures which have well-defined geometries and surface arrangements. The second part of the dissertation discusses the results from using AFM to study the earliest stages of the onset of water corrosion of copper surfaces with nanoscale resolution. Within a few hours of exposure to water of varying chemistries, dramatic differences in the morphology of copper surfaces were observed by ex situ AFM topography imaging. Surface characterizations of the treated copper samples were used systematically to evaluate changes for copper surfaces with various chemical treatments and to investigate mechanisms of passivation and corrosion.