Doctor of Philosophy / Department of Chemistry / Daniel A. Higgins / This doctoral thesis covers the synthesis, preparation, and characterization of a
series of four perylene diimide derivatives, and the nanofibrous composite materials
formed by these perylene diimides when complexed with oppositely charged
polyelectrolytes. The perylene diimides include a symmetric dication (TAPDI2+), a
symmetric dianion (PDISO32-), and two singly charged asymmetric varieties (C11OPDI+
and C7OPDI+) that contain a hydrophilic head group and hydrophobic ether tail. For all
studies presented in the following chapters, poly(acrylate) (PA-) or
poly(diallyldimethylammonium) chloride (PDDA+) are used as the polyelectrolytes
(PEs). The patterned deposition of sheer aligned, nanofibrous material within a fluidic
device is conclusively demonstrated. Thin films of the nanofibrous composite are
prepared from aqueous solutions of the semiconducting perylene diimides and oppositely
charged polyelectrolyte precursors. By sequentially exposing a clean glass substrate to
the cationic and anionic precursor solutions, a thin film of composite material is
deposited in a layer-by-layer fashion. By utilizing electrostatic self-assembly (ESA) and
layer-by-layer (LbL) procedures, precise control of film thickness and optical density are
obtained. The effect of perylene diimide structure and charge on resultant composite film
morphology is explored. Through spectroscopic and microscopic studies of bulk
perylene diimide solutions and composite thin films, it was determined that the formation
of these fibrous materials is dependent on the aggregation of the PDI within the precursor
solutions. The molecular orientation of the perylene diimide within the composite
nanofiber was determined to be perpendicular to the fiber long axis. For the special case
of C7OPDI+/PA- composite, flow induced fiber alignment was observed for both dip
coated and flow coated samples. The influence of solution flow profile, PE molecular
weight (MW), and PDI structure on deposition efficiency, macroscopic and microscopic
morphology, and the potential for nanofiber alignment are investigated. Film formation
mechanisms involving two unique routes are also presented.
| Identifer | oai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/3912 |
| Date | January 1900 |
| Creators | Everett, Thomas A. |
| Publisher | Kansas State University |
| Source Sets | K-State Research Exchange |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
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