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Dissertation
Electrospinning fluorescent hybrid polyelectrolyte ultra-fine fibers
Doctor of Philosophy (Ph.D.), Drexel University
Jun 2012
DOI:
https://doi.org/10.17918/etd-3764
Abstract
Nanofibers, by virtue of their extremely large surface area to volume ratio, promise to be an excellent platform to explore interactions of small volumes of analytes with the nanofiber-nanoparticle composite. Electrospinning is a facile nanofabrication technique that produces fibrous assemblies of ultra-fine fibers, 20-1000 nm in diameter, from a charged droplet of spinning solution. Optimization of the fiber diameter of a specific material system is dependent on the solution and process variables. Specifically we have established the electrospinning parameters for poly (acrylic acid) (PAA), chitosan in formic acid, polyelectrolyte complexes, and composites of these with quantum dots. The composite fibers exhibited uniform fiber morphologies and the fluorescence peak of the quantum dot composites was unchanged. In fact, fluorescence micrographs of the composite fibers reveal luminescent fibers with evenly distributed fluorophores that manifest SNP intermittency correlated with small clusters and single SNPs suggesting excellent dispersion in the polyelectrolyte matrix. These fluorescent composite fibrous assembles of nanoparticle-polyelectrolyte fibers are useful multifunctional materials, utilized in filtration, sensing and tissue engineering applications, with the added benefits of improved mechanical, electrical or structural characteristics over the individual components. To explore the sensing applications of these nonwoven assemblies we exposed the mats to a range of pHs and changes in humidity. The mats exhibited recoverable fluorescence quenching when exposed to high humidity and demonstrated sensitivity to changes in pH. The major impacts of this work include: (1) Electrospinning PAA/quantum dot composites for the first time and establishing the optical properties of these fibers. (2) Evaluation of the optical properties of these fibers when exposed to a range of pH's and humidity. (3) Electrospinning, for the first time, Chitosan/PAA complexed fibers with quantum dots. (4) Demonstrating, for the first time, the ability to regulate energy transfer between donor quantum dots embedded in a nanofiber and surface bound acceptors.
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Details
- Title
- Electrospinning fluorescent hybrid polyelectrolyte ultra-fine fibers
- Creators
- Jennifer S. Atchison - DU
- Contributors
- Caroline L. Schauer (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Materials (Science and) Engineering (Metallurgical Engineering) [Historical]; College of Engineering (1970-2026); Drexel University
- Other Identifier
- 3764; 991014632329904721