THE LIFECYCLE OF ADVANCED FIBERS: (I) A NEW METHOD FOR THE FABRICATION OF FIEBRS, (II) THE FUNCTIONALIZATION OF ELECTROSPUN PLA/PLA-B-PEG FIBERS, AND (III) THE DEGRADATION OF CELLULOSE FIBERS BY OXYGEN PLASMA

This dissertation covers a broad spectra of fiber research that includes (i) fabrication, (ii) functionalization, and (ii) physical/chemical degradation. In the first stage of this dissertation, a new method for fiber fabrication that combines electro- and wet- spinning, Immersion Electrospinning, was developed to direct fiber deposition by the selective application of voltage. Next, electrospun PLA/PLA-b-PEG (Poly(lactic acid)/Poly(lactic acid)-b-Poly(ethylene glycol) fibers were studied for stability over time (i.e. aged). Fiber properties were studied under humid conditions and water wicking properties of PLA/PLA-b-PEG fibers came to an equilibrium fairly quickly. While the ability to wick water was lessened with aging, PLA/PLA-b-PEG fibers could still wick more than PLA fibers. In the next study, biotin was then added to PLA/PLA-b-PEG fibers (where Dimethylformamide, DMF, was the solvent). PLA/PLA-b-PEG/biotin fibers resulted in a greater amount of biotin reaching the surface of fibers compared to PLA/biotin fibers. Water stability tests, however, showed a weight loss of the samples over 1 and 7 days, correlating with biotin and copolymer loss. To reduce this loss, two solvents were investigated, 1,1,1,3,3,3-Hexafluoro-2-propanol (HFIP) and DMF. In addition, the PLA-b-PEG block lengths were tailored. Biotin was attached directly to PLA-b-PEG. HFIP spun samples resulted in less copolymer loss than DMF spun samples, but there was no biotin present at the surface of fibers. By changing the block lengths of PLA-b-PEG, the amount of copolymer and biotin leaching was reduced using DMF as the solvent, and there was still theoretically, enough biotin present at the surface of fibers for use in detection. Lastly, plasma was used to decrease the stability of (i.e. degrade) cellulosic yarns. With the application of oxygen plasma, severe degradation of of high molecular weight cotton yarns was achieved