Fyzik

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Electrospun nanofibrous materials as X-ray
sources at atmospheric conditions
Pavel Pokorný, Petr Mikeš and David Lukáš
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Technical University of Liberec Czech Republic
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History
William Gilbert 1600 amber
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Self-organization
John Zeleny (1872-1951) Czech-American physicist
Taylor cone
1
1
Stable jet
Polymer solution
Whipping
d 200 nm
Solvent evaporation
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Self-organized nanofibrous layer
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Self-organization
E Ec
A rode instead of a needle
E 0













Stationary wave
d1cm
1
2
3
4
Epoxy resin
E
F.Sanetrník
Ec
no.
1 2 3 4 5 6
Sandra Torres
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5
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Technology
Jirsák, O. Sanetrník, F. Lukáš, D. Kotek, V.
Marinová, 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
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Physics
Needle Electrospinning
Capillary force
r
g
Elektrostatic force
h
permitivity
Force equilibrium !
Sir G. Taylor (1964) Disintegration of water
drops in an electric field, Proc. Roy. Soc. A,
vol. 280, 1964, pp. 383-397
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Physics
Needleless electrospinning
Dynamic phenomenon field strength increment can
lead to unlimited growth of a wave amplitude.
A. Sarkar
Wave vector
Amplitude
Angular frequency
Growth factor
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Physics
Stable amplitude
Growing amplitude
Dispersion law
Lukas D Sarkar A Pokorny P, Self organization of
jets in electrospinning from free liquid surface
- a generalized approach, accepted for
publication, Journal of Applied Physics, 103
(2008), 309-316.
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Physics
Tonks-Frenkel instability
Various field strengths
E
E
Stable waves of various wave numbers and angular
frequencies.
Fastest forming instability The only wave
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Experimental
L
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Experimental
b
32 kV
43 kV
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 l. The distance between the cleft and the
collector was adjusted on 802 mm.
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Electrospun nanofibrous materials as X-ray sources
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St. Elmos fire


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Taylor coun
D.H. Reneker, A.L. Yarin / Polymer 49 (2008)
2387-2425.
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P. Pokorný observation
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,
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Experimental setup
Setup with parallel and fixed gold- coated
nanofibers
Electrospinning setup
X-ray record
SEM microphotograph
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X-ray records
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.
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X-ray records
Kirlian photography
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SLP Silicon Lithium-Drifted Low-Energy X-Ray
Detector
Prof. Tomáš Cechák FJFI, CVUT Prague
-Premium performance spectroscopy from 1 keV to
30 keV -Energy resolution 35 eV -Thin Be window,
25 mm -Nitrogen cooled
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Electromagnetic spectrum of radiation
30kV/100 mm
30kV/100 mm
7,5kV/25 mm
15kV/50 mm
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Continuious bremsstrahlung and Discrete
characteristic radiation
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Continuious bremsstrahlung and Discrete
characteristic radiation
Spectra
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X-ray sources at atmospheric conditions
prefix
tera T 1012 giga G 109 mega M 106 kilo k 103
Richard P. Feynman Theres plenty of room at
the bottom. (1959)
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Macro and nano
MACRO
h 10 cm a 50 nm
NANO
NANO
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Warp of fibers
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Ionic clouds, Debye length, Manning region,
Counterion condensation
PoissonBoltzmann equation
8
-3
8 x 10
m
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Manning region
-

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).
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Conclusion
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.
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Acknowledgement
Antonín Kopal Konstantin Kornev
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Thank you for your attention. You are more than
welcome to an open discussion.
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Radon daughter deposition on electrostatically
charged surfaces
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
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Nanofibres
Lily
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History
Needleless Electrospinning
W.J. Morton Method of dispersing fluids, US
Patent, Seriál 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.
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History
Needle Electrospinning
John Zeleny (1872-1951) was a Czech-American
physicist at the University of Minnesota. His
work is seen by some as a beginning to emergent
technologies like liquid metal ion sources and
electrospraying and electrospinning.
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Technology
Scaling up the technology
1 g/hour
Needle arrays
Theron, Yarin, Zussman (2005) Polymer, 46
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Technology
Needleless Electrospinning
Yarin, Zussman (2004) Polymer, 34
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Needleless Electrospinning
Bubble Electrospinning Yong Liu, Ji-Huan
He International Journal of Nonlinear Sciences
and Numerical Simulation, 8(3),2007
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Physics
Stable amplitude
Growing amplitude Growing parameter
w is imaginary
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Physics
Euler equation
Landau equation
Velocity potential
Elektrostatic forces
gravitation
Surface tension
dispersion law
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Experimental
J. Zeleny, Phys. Rev. 3 (1914), p. 69
l
2r
Critical field strength for needle electrospinner.
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Experimental
Cleft spinner
43
Physics
Rayleigh instability
r0
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Experimental
32 kV
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Experimental
'Physical principles of electrospinning
(Electrospinning as a nano-scale technology of
the twentyfirst century)',Textile Progress,412,
59 -140, (2009).
1 cm
42 kV
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Polystyrene Density  1.060E00
(g/cm3)   Energy           t1/2          
(keV) (cm2/g) (mm) 1.00000E-03
2.040E03 0,00426 5.00000E-03 1.767E01
0,533 1.00000E-02 2.219E00
4,521 2.00000E-02 4.363E-01 21,622
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X- ray attenuation
http//physics.nist.gov/PhysRefData/XrayMassCoef/c
over.html Air, Dry (Near Sea Level) Density
1.205E-03 (g/cm3)   Energy         t1/e
  (keV) (cm2/g) (mm) 1 3.606E03
2,301 5 4.027E01 24,226 10 5.120E00
162,085 20 7.779E-01 1068,051   The mass
attenuation coefficient,
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Kirlian Photography
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.
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Single fiber
h 10-1 m a m
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The X-ray radiation
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X- ray tube
Crookes tubes invented by British physicist
William Crookes and others in1920s.