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Title: Atomic force microscopy on self-assembled polymer structures
Author: Glynos, Emmanouil
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2007
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In Part A we started our studies by investigating the morphology of physisorbed linear and star polybutadiene (PB) on a freshly cleaved mica surface from dilute solution after solvent evaporation . For the case of linear PB, we found that the dependence of the Mw on the observed polymer structures is crucial for samples with relatively high surface density where the interactions among the adsorbed polymers become significant. For a relatively high surface density we observed a tendency of the adsorbed polymers to aggregate for all the molecular weight molecules and an isotropic structural pattern was observed. We explained these structural phenomena with increasing surface density in terms of the molecular interactions of the adsorbed polymers when in good solvent conditions and after the abrupt solvent evaporation. For the case of star PB we present a study of the structure and growth of star shaped polymer monolayers on mica. The fine structure study revealed that the monolayer morphology depends strongly on the functionality (number of arms) of the star polymer. We studied poly(isoprene-b-ethylene oxide) block copolymer micelles on mica under ambient conditions (in our laboratory). We found that the time dependent behaviour of the polymeric islands arises from the surface 'aging’ of freshly cleaved muscovite mica from highly hydrophillic when freshly cleaved to less hydrophillic with the exposure time in ambient conditions. In part B the AFM is proposed for the first time as a tool to image the surface of polymer microbubbles at the nanometer range in liquid and to perform reproducible measurements on the nano/micro mechanical properties. We applied the AFM to assess structural aspects of the microbubble shell and probe their mechanical properties. As microbubbles are large objects compared to the overall size of usual AFM tips a convolution between the AFM tip and the microbubble was typical of the acquired topographies. However, a small part of the top of the bubble was imaged with nanometer resolution and roughness measurements are reported. Using contact mode AFM force-distance curves were captured and the range of stiffness (or effective spring constant) of BiSphere microbubbles was systematically measured.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available