Formation of Nanofibers via Electrospinning

Figure 1. A schematic diagram of the electrospinning process, showing the syringe, high voltage source and the collector plate.
    Fibers with diameters less than a micron can be formed using an electrospinning process where a droplet of a polymer solution is elongated by a strong electrical field. The resulting nanofibers are collected as nonwoven mats with extremely large surface to volume ratios which are being used, or finding uses, in filtration, protective clothing, biomedical applications and reinforced composites. The electrospinning process also has advantages for investigation of fiber formation processes with new materials and solvents including the ability to work with small sample sizes, rapid time scale of the spinning/solvent removal process and high elongation of as spun fibers. We have been working on nanofibers formation of various advanced materials: i) inorganic nanofibers using
electrospinning/sol-gel method, ii) polymer-inorganic nanocomposites, iii) newly developed biodegradable polymers. We would like to explore the possibility of tailoring the properties of these fibers on a nanoscale (~ 100 nm) via the electrospinning process. The group is also involved in continuum modeling of the fluid jet of the electrospinning process and the instability that the jet experiences while travelling to the collector.
     The main focus of current research is the control of nanoscale structures in nanofibers. For example, we have demonstrated that electrospinning of self-assembling block copolymers gives rise to unique self-assembly morphology due to both elongational deformation and cylindrical confinement during electrospinning. In particular, our recent coaxial electrospinning studies where PS-b-PI block copolymer is enveloped by a silica sheath showed that these unique morphologies such as stacked disks and axially aligned concentric rings can be controlled by molecular weights and degree of deformation and annealing (Fig. 2 a). We have combined the sol-gel synthesis and electrospinning to develop inorganic nanofibers. We have been able to incorporate various metal oxide crystal phases such as TiO2, ZrO2, Fe3O4 and V2O5 (Fig. 2 b). in silica or carbon nanofibers. In the study of electrospinning polymer/nanoclay composites we have found out that nanoclay can be easily aligned through the entire electrospun fibers and enhance the degree of crystalinnity (Fig 2. c). As a result, the improvement in mechanical properties of electrospun fibers by nanoclay inclusion can be much more substantial than in conventional films and fibers.
Figure 2. Nanostrucutred nanofibers a) via directed assembly (left), b) formation of nanocrystals (middle) and c) inclusion of nanoclays (right).

 Publications on Nanofiber Modeling

  • E. Zhmayev, D. Cho and Y.L. Joo, "Electrohydrodynamic Quenching in Polymer Melt Electrospinning", Physics of Fluids 23, 073102 (2011).
  • C.P. Carroll and Y.L. Joo, "Discretized Modelling of Electrically Driven Viscoelastic Jets in the Initial Stage of Electrospinning", Journal of Applied Physics 109, 094315 (2011).
  • E. Zhmayev, D. Cho and Y.L. Joo, "Nanofibers from Gas-Assisted Polymer Melt Electrospinning", Polymer 51, 4140-4144 (2010).
  • E. Zhmayev, D. Cho and Y.L. Joo, "Modeling of Melt Electrospinning for Semi-Crystalline Polymers", Polymer 51, 274-290 (2010).
  • C.P. Carroll and Y.L. Joo, "Axisymmetric Instabilities in Electrospinning of Highly Conducting, Viscoelastic Polymer Solutions", Physics of Fluids 21, 103101 (2009).
  • V. Kalra, J.H. Lee, J. Park, M. Marquez and Y.L. Joo, "Confined Assembly of Asymmetric Block Copolymer Nanofibers via Multi-axial Jet Electrospinning", Small 5, 2323-2332 (2009).
  • C.P. Carroll and Y.L. Joo, "Axisymmetric Instabilities of Electrically Driven Viscoelastic Jets", Journal of Non-Newtonian Fluid Mechanics 153, 130-148 (2008).
  • E. Zhmayev, H. Zhou and Y.L. Joo, "Modeling of Non-isothermal Polymer Jets in Melt Electrospinning", Journal of Non-Newtonian Fluid Mechanics 153, 95-108 (2008).
  • C.P. Carroll and Y.L. Joo, "Electrospinning of Viscoelastic Boger Fluids: Modeling and Experiments", Physics of Fluids 18, 053102-14 (2006).

Selected Publications on Electrospun Nanofibers

  • J. Yin, J.M. Carlin, J. Kim, Z. Li, J.H. Park, B. Patel, S. Chakrapani, S. Lee, and Y.L. Joo, "Synergy between Metal Oxide Nanofibers and Graphene Nanoribbons for Rechargeable Lithium-Oxygen Battery Cathodes", Advanced Energy Materials, in press, 2014.
  • Y.S. Kim, W.B. Kim, and Y.L. Joo, "Further Improvement of Battery Performance via Charge Transfer Enhanced by Solution-Based Antimony Doping into Tin Dioxide Nanofibers", Journal of Materials Chemistry A 2, 2833-2837 (2014). 
  • J.H. Park, and Y.L. Joo, "Tailoring Nanorod Alignment in a Polymer Matrix by Elongational Flow under Confinement: Simulation, Experiments and Surface Enhanced Raman Scattering Application", Soft Matter 10, 3494-3505 (2014).  
  • Y.S. Kim, K.W. Kim, D. Cho, N.S. Hansen, J. Lee, and Y.L. Joo, "Silicon-Rich Carbon Hybrid Nanofibers from Water-Based Spinning: The Synergy Between Silicon and Carbon for Li-ion Battery Anode Application", ChemElectroChem 1, 220-226 (2014).
  • D. Cho, A. Naydich, M.W. Frey and Y.L. Joo, "Further Improvement of Filtration Efficiency of Cellulose Filters Coated with Nanofibers via Inclusion of Electrostatically Active Nanoparticles", Polymer 54, 2364-2372 (2013).
  • N.S. Hansen, D. Cho, and Y.L. Joo, "Metal Nanofibers with Highly Tunable Electrical and Magnetic Properties via Highly Loaded Waster Based Electrospinning", Small 8, 1510-1514 (2012).
  • Y. Cho, D. Cho, J.H. Park, M.W. Frey, C.K. Ober, and Y.L. Joo, "Preparation and Characterization of Amphiphilic Triblock Terpolymer-Based Nanofibers as Antifouling Biomaterials", Biomacromolecules 13, 1606-1614 (2012).
  • D. Cho, A. Netravali, and Y.L. Jpp, "Mechanical Properties and Biodegradability of Electrospun Soy Protein Isolate/PVA Nanofibers", Polymer Degradation and Stability 97, 747-754 (2012).
  • N.S. Hansen, T.E. Furguson, J.E. Panels, A.A. Park and Y.L. Joo, "Inorganic Nanofibers with Tailored Placement of Nanocatalysts for the Hydrogen Production via Alkaline Hydrolysis of Glucose", Nanotechnology 22, 325302 (2011).
  • D. Cho, H. Zhou, and Y.L. Joo, "Structural Studies of Electrospun Nylon 6 Fibers from Solution and Melt", Polymer 52, 4600-4609 (2011).
  • D. Cho, H. Zhou, Y. Cho, D. Audus, and Y.L. Joo, "Structural Studies and Hydrophobicity of Electrospun Polypropylene Fibers from Solution and Melt", Polymer 51, 6005-6012 (2010).
  • M. Kamperman, L.T.J. Korley, B. Yau, K.M. Johansen, Y.L. Joo, U. Wiesner, "Nanomanufacturing of Continuous Composite Nanofibers with Confinement-induced Morphologies", Polymer Chemistry 1, 1001-1004 (2010).
  • V. Kalra, J.H. Lee, J. Park, M. Marquez and Y.L. Joo, "Confined Assembly of Asymmetric Block Copolymer Nanofibers via Multi-axial Jet Electrospinning", Small 5, 2323-2332 (2009).
  • V. Kalra, J. Lee, J.H. Lee, S.G. Lee, M. Marquez, U. Wiesner, Y.L. Joo, "Controlling Nanoparticle Location via Confined Assembly in Electrospun Block Copolymer Nanofibers", Small 4, 2067-2073 (2008).
  • J.E. Panels, J. Lee, K.Y. Park, S.Y. Kang, M. Marquez, U. Wiesner, Y.L. Joo, "Synthesis and Characterization of Magnetically Active Carbon Nanofiber/Iron Oxide Composites with Hierarchical Pore Structures", Nanotechnology 19, 455612 (2008).
  • H.J. Park, J.W. Dingee, S.R. Fitzgibbon, A.B. Anton, Y.L. Joo, "Controlling Cellulose Microstructure via Electrospinning with Applications in Enzymatic Hydrolysis", Journal of Biobased Materials and Bioenergy 1, 245-256 (2007).
  • V. Karla, S. Mendez, J.H. Lee, H. Nguyen, M. Marquez, and Y.L. Joo, "Confined Assembly of Coaxially Electrospun Block Copolymer Fibers", Advanced Materials 18, 3299-3303 (2006).
  • V. Karla, P.A. Kakad, S. Mendez, T. Ivannikov, M. Kamperman, and Y.L. Joo, "Self-Assembled Structures in Electrospun PS-b-PI Copolymers Fibers", Macromolecules 39, 5453-5457 (2006).
  • H. Zhou, T.B. Green, and Y.L. Joo, "The Thermal Effects on Electrospinning of Polylactic Acid Melts",Polymer 47, 7497-7505 (2006).
  • J.E. Panels and Y.L. Joo, "Incorporation of Vanadium Oxide in Silica Nanofiber Mats via Electrospinning and Sol-gel Synthesis", Journal of Nanomaterials 2006, 41327 (2006).
  • C.W. Kim, D.S. Kim, S.Y. Kang, M. Marquez and Y.L. Joo, "Structural Studies of Electrospun Cellulose Nanofibers", Polymer, 47 5097-5107 (2006).
  • H. Zhou, K.W. Kim, E.P. Giannelis, Y.L. Joo, "Nanofibers from Poly (L-Latic) Acid Nanocomposites: Effects of Nanoclay on Molecular Structures" in Polymeric Nanofibers, ACS Symposium Series Book 918, 217-230 (2006).
  • C.W. Kim, M.W. Frey, M. Marquez and Y.L. Joo, "Preparation of Electrospun Cellulose Nanofibers via Direct Dissolution", Journal of Polymer Science: Part B: Polymer Physics 43, 1673-1683 (2005).
  • S.S. Choi, S.G. Lee, S.S. Im, S.H. Kim and Y.L. Joo, "Silica Nanofibers from Electrospinning/Sol-Gel Process", Journal of Materials Science Letters 22, 891-893 (2003)