6. NANOFIBERS Figure 4. Ultra – Web® Nanofiber Filter Media used commercially. (taken from Grafe, 2003)
7. First nanofibers produced in the Material Science Lab, IMSP, UPLB Figure 5.Polycaprolactonenanofiber (a) and (b) has fiber diameters between 273 nm to 547 nm. SEM taken with 10,000X magnification. (J.I.Zerrudo, E.A.Florido, 2008)
8. First nanofibers produced in the Material Science Lab, IMSP, UPLB Figure 6. 75:25 Polycaprolactone(PCL)/Polyethylene Oxide (PEO) blend nano10,000X magnification. (J.I.Zerrudo, E.A.Florido, SPP Physics Congress, October 2008)
9. First nanofibers produced in the Material Science Lab, IMSP, UPLB Figure 7. SEM Micrograph of Poly(DL-lactide-co-glycolide) nanofibers With diameter range of 59nm-126 nm. (J.Clarito, E.A.Florido, October 2008)
10. First nanofibers produced in the Material Science Lab, IMSP, UPLB Figure 8. SEM Micrograph of Poly(DL-lactide-co-glycolide) nanofibers with diameters of 86 nm, 194 nm, 201 nm. (J.Clarito, E.A.Florido, October 2008)
11. First nanofibers produced in the Material Science Lab, IMSP, UPLB Figure 9. SEM Micrograph of Poly(DL-lactide-co-glycolide) nanofiber mesh. (J.Clarito, E.A.Florido, October 2008)
12. First nanofibers produced in the Material Science Lab, IMSP, UPLB Figure 10. SEM Micrograph of Polyvinyl chloride nanofiber with at least 76 nm diameter. (J.Garcia, E.A.Florido, February 2009)
13. First nanofibers produced in the Material Science Lab, IMSP, UPLB Figure 11. 22 nm-diameter polyvinyl chloride nanofiber with a porous microfiber in the background. (J.Garcia, E.A.Florido, February 2009)
14.
15. Tissue and Organ Implants (RAMAKRISHNA, S.M., et al. 2004)
16.
17.
18. The high voltage produces an electrically charged jet of polymer solution or melt, which dries or solidifies leaving a polymer fiber
19.
20. ELECTROSPINNING Figure 13 The distribution of charge in the fiber changes as the fiber dries out during flight
21. Figure 14. Electrospinning set-up in the IMSP Physics Division Materials Science Laboratory. J.I.Zerrudo, E.A. Florido
22.
23.
24.
25. was described by Sir Geoffrey Ingram Taylor in 1964 before electrospray was "discovered“
26.
27. Taylor Cone Potential Equipotential surface The zero of the Legendre polynomial between 0 and pi is 130.70990 which is the complement (supplement) of the Taylor angle.
28. Taylor Cone When a sufficiently high voltage is applied to a liquid droplet, the body of the liquid becomes charged, and electrostatic repulsion counteracts the surface tension and droplet is stretched, at a critical point a stream of liquid erupts from the surface. This point of eruption is known as the Taylor cone
36. Electrospinning v=0.1m/s moving charges e bending force on charge e E ~ 105V/m viscoelastic and surface tension resistance Moving charges (ions) interacting with electrostatic field amplify bending instability, surface tension and viscoelasticity counteract these forces NANOFIBRES T. A. Kowalewski, A. L. Yarin & S. Błoński, EFMC 2003, Toulouse
37. Electro-spinning Simple model for elongating viscoelastic thread Stress balance: - viscosity, G – elastic modulus stress, stress tensor, dl/dt – thread elongation Momentum balance: Vo – voltage, e – charge, a – thread radius, h- distance pipette-collector Kinematic condition for thread velocity v Non-dimensional length of the thread as a function of electrostatic potential NANOFIBRES T. A. Kowalewski, A. L. Yarin & S. Błoński, EFMC 2003, Toulouse
38. Electro-spinning bending instability of electro-spun jet charges moving along spiralling path E ~ 105V/m Bending instability enormously increases path of the jet, allowing to solve problem: how to decrease jet diameter 1000 times or more without increasing distance to tenths of kilometres NANOFIBRES T. A. Kowalewski, A. L. Yarin & S. Błoński, EFMC 2003, Toulouse
39. Parameters Molecular Weight, Molecular-Weight Distribution and Architecture (branched, linear etc.) of the polymer Solution properties (viscosity, conductivity & and surface tension) Electric potential, Flow rate & Concentration Distance between the capillary and collection screen Ambient parameters (temperature, humidity and air velocity in the chamber) Motion of target screen (collector)
40. Figure 14. Electrospinning set-up in the IMSP Physics Division Materials Science Laboratory. J.I.Zerrudo, E.A. Florido
50. Electrospinning in MatPhy Lab, IMSP, UPLB PEO microfibers, JennetteRabo, Maricon R. Amada, 2006 Polyaniline and Polyaniline/Polyester microfibers, Jefferson D. Diego, M.R.Amda, Emmanuel A. Florido, 2006 Polycaprolactone/Polyethylene Oxide nanofibers, Juzzel Ian Zerrudo, Emmanuel A. Florid0, 2008 Polycaprolactone (pcl)/Polyethylene oxide (peo)/iota carrageenan (ιcar) blends, Serafin M. Lago III, Teoderick Barry R. Manguerra, 2008.
51. Electrospinning in MatPhy Lab, IMSP, UPLB 4. Poly (DL-lactide-co-glycolide)(85:15) PLGA and PLGA/Polycaprolactone (PCL) nanofibers, Christian Joseph Clarito, Emmanuel A. Florido, 2008 5. Polyvinyl Chloride (PVC) nanofibers from scrap PVC pipes, Ben Jairus T. Garcia, 2009
52. Nanoresearch in UPLB: Physics Division, Institute of Mathematical Sciences and Physics, CAS K.S.A. Revelar. An Investigation on the Morphological and Antimicrobial Properties of Electrospun Silver Nanoparticle-Functionalized Polyvinyl Chloride Nanofiber Membranes. IMSP, UPLB. April 2010. Undergraduate Thesis, Adviser: EAFlorido. Co-Adviser: R.B.Opulencia A.O.Advincula. Effect of varying Areas of Parallel Plates on Fiber Diameter of Electrospun Polyvinyl Chloride. IMSP, UPLB. April 2010. Undergraduate Thesis, Adviser: EAFlorido H.P.Halili. Effect of Solution Viscosity and Needle Diameter on Fiber Diameter of ElectrospunPolycaprolactone. IMSP, UPLB. October 2010. Undergraduate Thesis, Adviser: EAFlorido. Co-Adviser: J.I.B. Zerrudo
53. J.C.M. La Rosa. Effects of Variation of Distance Between Needle Tip and Collector On the Fabrication of Polyaniline (PANI)-Polyvinyl Chloride (PVC) Blend Nanofibers. IMSP, UPLB. April 2009. Undergraduate Thesis, Co-Adviser: EAFlorido M.J.P.Gamboa. The Effects of Viscosity on the Morphological Characteristics of ElectrospunPolyaniline-Polyvinyl Acetate (PAni-PVAc) Nanofibers. IMSP, UPLB. April 2009. Undergraduate Thesis, Co-Adviser: EAFlorido J.I.B. Zerrudo, E.A. Florido, M.R. Amada, Fabrication of PolycaprolactoneNanofibers through Electrospinning, Proceedings of the SamahangPisikangPilipinas, ISSN 1656-2666, vol. 5,October 22-24, 2008.
54. J.I.B. Zerrudo, E.A. Florido, M.R. Amada, B.A.Basilia, Fabrication of Polycaprolactone/Polyehtylene Oxide Nanofibers through Electrospinning, Proceedings of the SamahangPisikangPilipinas, ISSN 1656-2666, vol. 5,October 22-24, 2008. B.J.Garcia. Morphological and Molecular Characterization of Electrospun Polyvinyl chloride-PolyanilineNanofibers. IMSP, UPLB. April 2009. Undergraduate Thesis, Adviser: EAFlorido J.D. Diego. Electrospinning of Polyaniline and Polyaniline/Polyester Based Fibers. IMSP, UPLB. November 2006.Undergraduate Thesis, Adviser: EAFlorido