Photonic crystals in biology - NanoTR-VI

Poster Session, Thursday, June 17Theme F686 - N1123Morphology of the Electrospun Nylon-66 and Polybutylene terephthalate NanofibersFatma Kayacı and Tamer Uyar*UNAM-Institute of Materials Science & Nanotechnology, Bilkent University, Ankara, 06800, TurkeyAbstract – This work covers our recent studies on fabrication of polymeric nanofibers by electrospinning technique.Nanofibers/nanowebs of Nylon-66 (PA66) and Polybutylene terephthalate (PBT) have been obtained by electrospinning andthe morphology of the resulting nanofibers/nanowebs was investigated by scanning electron microscope (SEM) .Electrospinning is the most versatile method forfabrication of nanofibers, since it is a simple andcost effective technique. The nanofibers can beelectrospun from a wide range of polymers that aresoluble in various solvent systems. In addition, theability to produce nanofibers/nanowebs which haveunique properties like small pore size, large surfacearea to volume ratio, high porosity makeelectrospun nanofibers more attractive for manyapplications such as filtration, textile, tissueengineering, wound healing, release control,sensors, energy, etc [1-6]. Electrospinning is asimple process in which a polymer solution or meltis subjected to high voltage (10 kv- 60 kv) and thefibers which have diameter in the range of fewmicrons to few hundred nanometers are produced inthe form of nonwoven [4-8].Nylon-66 is an important semi-crystallinethermoplastic polymer having mechanical strength,chemical resistance, toughness, and dimensionalstability. Therefore, nylon-66 is one of the mostused polymers for numerous applications such astechnical texiles, filtration, and especiallyengineering field [7,8]. Polybutylene terephthalate(PBT), a linear polyester of aromatic nature, is alsoone of the important engineering plastics due to itsgood mechanical, and thermal properties [9].In this study, Nylon 66 and PBTnanofibers/nanowebs were obtained byelectrospinning. Formic acid/chloroform (75/25)and hexafluoroisopropanol (HFIP) were used assolvent for Nylon-66 and PBT, respectively.Polymer concentration, tip-to-collector distance andapplied voltage were optimized in order to obtainbead-free uniform nanofibers.Fig.1.SEM images of electrospun fibers from formic acid/chloroform (75/25) solution (a) 5% PA66, (b) 10% PA66Different fiber morphologies were obtained forNylon-66 and PBT electrospun nanofibers whendifferent polymer concentrations were used (fig.1and fig.2). Beads were formed when the polymerconcentration was low for both of polymers. Whenthe polymer concentration was increased, typicalcircular fibers were obtained for PBT; however,ribbon-like fibers were obtained for Nylon-66because of the rapid evaporation of the solvent. Itwas also observed that the diameter of the fiberswere increased as the polymer concentrationincreased or tip-to-collector distance and appliedvoltage decreased.Figure 2. SEM images of electrospun fibers HFIPsolutions (a) 15% PBT, (b) 20% PBT* Corresponding author (uyar@unam.bilkent.edu.tr)[1] Ramakrishna, S.; Fujihara, K.; Teo, W.; Yong, T.;Ma, Z.; Ramaseshan, R., Electrospun nanofibers: solvingglobal issues. Materials today 2006, 9 (3), 40-50.[2] Li, D.; Xia, Y., Electrospinning of nanofibers:Reinventing the wheel? Advanced Materials 2004, 16(14), 1151-1170.[3] Fang, J.; Niu, H.; Lin, T.; Wang, X., Applications ofelectrospun nanofibers. Chinese Science Bulletin 2008,53 (15), 2265-2286.[4] Huang, Z.; Zhang, Y.; Kotaki, M.; Ramakrishna, S., Areview on polymer nanofibers by electrospinning andtheir applications in nanocomposites. Composites Scienceand Technology 2003, 63 (15), 2223-2253.[5] Greiner, A.; Wendorff, J., Electrospinning: afascinating method for the preparation of ultrathin fibers.Angewandte Chemie-International Edition 2007, 46 (30),5670-5703.[6] Burger, C.; Hsiao, B.; Chu, B., Nanofibrous materialsand their applications. 2006.[7] Jeong, J.; Jeon, S.; Lee, T.; Park, J.; Shin, J.;Alegaonkar, P.; Berdinsky, A.; Yoo, J., Fabrication ofMWNTs/nylon conductive composite nanofibers byelectrospinning. Diamond & Related Materials 2006, 15(11-12), 1839-1843.[8] Pan, Z.; Liu, H.; Wan, Q., Morphology andMechanical Property of Electrospun PA 6/66 CopolymerFilament Constructed of Nanofibers.[9] Xiao, J.; Hu, Y.; Wang, Z.; Tang, Y.; Chen, Z.; Fan,W., Preparation and characterization of poly (butyleneterephthalate) nanocomposites from thermally stableorganic-modified montmorillonite. European PolymerJournal 2005, 41 (5), 1030-10336th Nanoscience and Nanotechnology Conference, zmir, 2010 781