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<p>Engineering thin, organic materials with tailored properties requires both the
understanding of the conformation of thin organic films and their conformational response
to changes in the environment, and the accurate characterization the mechanical properties
of the materials as a thin layer on surfaces. These issues have not yet been sufficiently
addressed due to the paucity of appropriate tools and data interpretation approaches
to reveal the nanometer scale conformation and mechanics of surface-grafted, thin,
organic films. In this dissertation, I report on the characterization of conformational
and mechanical properties of thin organic films, and the development of techniques
that allow more detailed and reliable measurement of these material properties. First,
I co-developed a novel approach to evaluate neutron reflectivity data and to simulate
the conformational structure for thin stimulus-responsive polymer brushes. In this
approach, we used a molecular-based lattice mean-field theory, augmented with experimentally
obtained parameters to describe the polymer chains. The approach and fitting results
required fewer fitting parameters, and captured the thermal response of the sample
self-consistently. </p><p>Second, I demonstrated the capability of force-modulation
microscopy in imaging surface-grafted, organic thin films in aqueous environments,
with high spatial resolution and sensitivity to conformational details that affect
the contact mechanics. To this end, I developed a new parameter-selection approach.
This approach allowed both highly sensitive mapping of subtle differences in the molecular
packing of thiol molecules on the substrate surface, and generation of high-contrast
contact-stiffness images of end-grafted protein patterns on a surface. Finally, I
discussed model selection and error estimation in calculating the reduced Young's
modulus of soft materials on surfaces. I found that the detailed characterization
of probe apex profiles, using probe-reconstruction techniques, provide only marginal
improvements in calculating the reduced Young's modulus of thin films, compared with
analytical models of equivalent probe radii; however, I found that a hybrid worn-cone
model is appropriate for large indentations on soft materials, and benefits from the
characterization of the probe apex profile. Additionally, we rendered error maps of
several common scenarios, referenced to indentation and probe radius values, in the
determination of the reduced Young's modulus.</p>
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