Electrospun nanofibrous materials as X-ray sources at atmospheric conditions Pavel Pokorn½,...

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Transcript of Electrospun nanofibrous materials as X-ray sources at atmospheric conditions Pavel Pokorn½,...

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Electrospun nanofibrous materials as X-ray sources at atmospheric conditions Pavel Pokorn, Petr Mike and David Luk 1Electrospinning - X-rays Slide 2 2 Technical University of Liberec Czech Republic Slide 3 Clemson UniversityElectrospinning - X-rays3 William Gilbert 1600 amberHistory Slide 4 Clemson UniversityElectrospinning - X-rays4 Solvent evaporation Whipping Taylor cone Stable jet d =200 nm 1 1 2 Polymer solution Self-organized nanofibrous layerSelf-organization John Zeleny (1872-1951) Czech-American physicist Slide 5 5 Epoxy resin E no. 1234 6 Self-organization 1 2 3 4 5 6 E = 0 E = E c EcEcEcEc A rode instead of a needle 5 d=1cm + + + + + + +++ + +++ Stationary wave F.Sanetrnk Sandra Torres Slide 6 Clemson UniversityElectrospinning - X-rays6 Technology Jirsk, O. Sanetrnk, F. Luk, D. Kotek, V. Marinov, L. Chaloupek, J. (2005) WO2005024101 A Method of Nanofibres Production from A Polymer Solution Using Electrostatic Spinning and A Device for Carrying out The Method. www.elmarco.com Slide 7 Clemson UniversityElectrospinning - X-rays7 Capillary force Elektrostatic force Force equilibrium ! r h Physics Sir G. Taylor (1964) Disintegration of water drops in an electric field, Proc. Roy. Soc. A, vol. 280, 1964, pp. 383- 397 Needle Electrospinning permitivity Slide 8 Clemson UniversityElectrospinning - X-rays8 Wave vector Angular frequency Physics Needleless electrospinning Dynamic phenomenon: field strength increment can lead to unlimited growth of a wave amplitude. A. Sarkar Growth factor Amplitude Slide 9 Clemson UniversityElectrospinning - X-rays9 Stable amplitude Growing amplitude Physics Lukas D Sarkar A Pokorny P, S ELF ORGANIZATION OF JETS IN ELECTROSPINNING FROM FREE LIQUID SURFACE - A GENERALIZED APPROACH, ACCEPTED FOR PUBLICATION, Journal of Applied Physics, 103 (2008), 309-316. Dispersion law Slide 10 Clemson UniversityElectrospinning - X-rays10 Stable waves of various wave numbers and angular frequencies. Fastest forming instability The only wave Physics Various field strengths E E Tonks-Frenkel instability Slide 11 Clemson UniversityElectrospinning - X-rays11 Experimental Slide 12 Clemson UniversityElectrospinning - X-rays12 Linear clefts emit polymeric jets. Linear clefts in (a) and (b) emit polymeric (polyvinyl alcohol) jets at the voltages, 32 kV and 43 kV, respectively. The inter-jet distance / wavelength is. The distance between the cleft and the collector was adjusted on 802 mm. b 32 kV43 kV Experimental Slide 13 13Clemson UniversityElectrospinning - X-rays Electrospun nanofibrous materials as X-ray sources Slide 14 + + Clemson University14 St. Elmos fire Slide 15 D.H. Reneker, A.L. Yarin / Polymer 49 (2008) 2387-2425. 15 Taylor coun Slide 16 First observation of radiation recorded in X-ray sensitive film. 16 Shield: -black paper, 160 g/m -2 -Aluminum foil, 0.01 mm, 25 gm -2. Deutherium lamp HERAEUS D200F, 300W, UV light,160 nm- 400 nm, i.e. 120 eV - 50 eV, Clemson UniversityElectrospinning - X-rays P. Pokorn observation Slide 17 Electrospinning setup Setup with parallel and fixed gold- coated nanofibers X-ray record SEM microphotograph Clemson University Experimental setup Slide 18 The detected radiation arose from the vicinity of freshly electrospun nanofibres as proven by the geometrical similarity of the tracks recorded on a radiographic film and the location of deposited nanofibrous heaps. 18 X-ray records Slide 19 19Clemson University X-ray records Kirlian photography Slide 20 -Premium performance spectroscopy from 1 keV to 30 keV -Energy resolution 35 eV -Thin Be window, 25 m -Nitrogen cooled Prof. Tom echk FJFI, VUT Prague 20Clemson UniversityElectrospinning - X-rays SLP Silicon Lithium-Drifted Low-Energy X-Ray Detector Slide 21 21 Electromagnetic spectrum of radiation Slide 22 22 Continuious bremsstrahlung and Discrete characteristic radiation Slide 23 Spectra 23 Continuious bremsstrahlung and Discrete characteristic radiation Slide 24 24 Richard P. Feynman: Theres plenty of room at the bottom. (1959) teraT10 12 gigaG10 9 megaM10 6 kilok10 3 prefix X-ray sources at atmospheric conditions Slide 25 25 MACRO NANO Clemson UniversityElectrospinning - X-rays Macro and nano NANO h = 10 cm a = 50 nm Slide 26 26Clemson UniversityElectrospinning - X-rays Warp of fibers Slide 27 8 x 10 8 m -3 Clemson University27Electrospinning - X-rays Ionic clouds, Debye length, Manning region, Counterion condensation PoissonBoltzmann equation Slide 28 - + Kornev K. Lateral interactions of charges in thin liquid films and the Berezinskii-Kosterlitz-T houless transitiv, Physical Review E, 60 (4), 8554-8559 (1999). 28 Manning region Slide 29 29 Needleless electrospinning is promising industrial technology. It will be worthwhile to investigate x-ray emission from nanofibrous electrodes in a more intensive manner, since it could find applications in a lot of fields. Clemson UniversityElectrospinning - X-rays Conclusion Slide 30 Clemson UniversityElectrospinning - X-rays30 Antonn Kopal Konstantin Kornev Acknowledgement Slide 31 Thank you for your attention. You are more than welcome to an open discussion. 31 Slide 32 Radon daughter deposition on electrostatically charged surfaces Background level Measurement by Geiger Muller detectror Radiant energy ranges of Gamma-radiation: from 0,06 to 1,2 MeV Radiant energy ranges of Beta-radiation: from 0,5 to 3 MeV 32Clemson UniversityElectrospinning - X-rays Slide 33 33 Lily Nanofibres Slide 34 Clemson UniversityElectrospinning - X-rays34 W.J. Morton: Method of dispersing fluids, US Patent, Seril No. 705,691, July 29, 1902 (Application 1900) Electrical method where volatile fluids are separated from their combination or association with relatively non-volatile or fixed substances in composite fluids.History Needleless Electrospinning Slide 35 Clemson UniversityElectrospinning - X-rays35 John Zeleny (1872-1951) was a Czech-American physicist at the University of Minnesota. CzechAmerican physicist University of Minnesota CzechAmerican physicist University of Minnesota His work is seen by some as a beginning to emergent technologies like liquid metal ion sources and electrospraying and electrospinning. electrospraying electrospinning electrospraying electrospinningHistory Needle Electrospinning Slide 36 Clemson UniversityElectrospinning - X-rays36 Technology Theron, Yarin, Zussman (2005) Polymer, 46 Needle arrays Scaling up the technology 1 g/hour Slide 37 Clemson UniversityElectrospinning - X-rays37 Yarin, Zussman (2004) Polymer, 34 Needleless Electrospinning Technology Slide 38 Clemson UniversityElectrospinning - X-rays38 Needleless Electrospinning Bubble Electrospinning Yong Liu, Ji-Huan He International Journal of Nonlinear Sciences and Numerical Simulation, 8(3),2007 Slide 39 Clemson UniversityElectrospinning - X-rays39 Stable amplitude Growing amplitude Growing parameter is imaginary Physics Slide 40 Clemson UniversityElectrospinning - X-rays40 Euler equation Landau equation gravitation Surface tension Elektrostatic forces Physics dispersion law Velocity potential Slide 41 Clemson UniversityElectrospinning - X-rays41 Critical field strength for needle electrospinner. Experimental 2r J. Zeleny, Phys. Rev. 3 (1914), p. 69 Slide 42 Clemson UniversityElectrospinning - X-rays42 Experimental Cleft spinner Slide 43 Clemson UniversityElectrospinning - X-rays43 Rayleigh instability rr0rr0 Physics Slide 44 Clemson UniversityElectrospinning - X-rays44 32 kV Experimental Slide 45 Clemson UniversityElectrospinning - X-rays45 42 kV 'Physical principles of electrospinning (Electrospinning as a nano-scale technology of the twentyfirst century)',Textile Progress,41:2, 59 -140, (2009). Experimental 1 cm Slide 46 46 Polystyrene Density =1.060E+00 (g/cm 3 ) Energy t 1/2 Energy t 1/2 (keV) (cm 2 /g) (mm) 1.00000E-03 2.040E+03 0,00426 5.00000E-03 1.767E+01 0,533 1.00000E-02 2.219E+00 4,521 2.00000E-02 4.363E-01 21,622 Clemson UniversityElectrospinning - X-rays Slide 47 47 http://physics.nist.gov/PhysRefData/XrayMassCoef/cover.html Air, Dry (Near Sea Level) Density= 1.205E-03 (g/cm 3 ) Energy t 1/e Energy t 1/e (keV) (cm 2 /g) (mm) 1 3.606E+03 2,301 1 3.606E+03 2,301 5 4.027E+01 24,226 5 4.027E+01 24,226 10 5.120E+00 162,085 207.779E-01 1068,051 The mass attenuation coefficient, Clemson UniversityElectrospinning - X-rays X- ray attenuation Slide 48 Clemson UniversityElectrospinning - X-rays48 Kirlian photography: If an object on a photographic plate is connected to a source of high voltage, small corona discharges (created by the strong electric field at the edges of the object) create an image on the photographic plate.photographic platecorona dischargeselectric field Kirlian Photography Slide 49 h = 10 -1 m a = m 49 Single fiber Slide 50 50 The X-ray radiation Slide 51 51Clemson University Crookes tubesCrookes tubes: invented by British physicist William Crookes and others in1920s. William Crookes tubesWilliam Crookes X- ray tube