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Electrospinning –
modifications
Direct current – DC
Nanofibrous thread (yarn) production
Bicomponent fibers
Porous fibers
Manufacture of thread
through electrospinning
Spinning from the liquid surface
Manufacture of thread
through electrospinningSpinning onto the liquid surface
Manufacture of thread
through electrospinningSpinning onto the liquid surface
Nanofibers and Nanotechnology in Textiles
P. Brown,K Stevens
Manufacture of thread through
electrospinning
Two opposite jets
Nanofibers and Nanotechnology in Textiles
P. Brown,K Stevens
Manufacture of thread through
electrospinning
Two opposite jets
Manufacture of thread through
electrospinning
Two opposite jets
Manufacture of thread through
electrospinning
twisting
Manufacture of thread through
electrospinning
Twisting
|16.1.2015
Parallelized nanofibers
Linear structures
Nanoyarns
Nanofibers
+ 3D printing
Manufacture of thread through electrospinning
twisting
průtah
zákrut
Manufacture of thread through
electrospinning
Bicomponent fibers
Mainly by Needle DC electrospinning
- Core/shell or Core/sheath or
Coaxial fibers (hollow fibers)
- Side-by-side fibers
Bicomponent fibersCoaxial or Core/sheath fibersNeedle electrostatic spinning (DC electrospinning) - usually only the sheath is electricallycharged, the core is extracted by contact friction between liquids.
https://www.youtube.com/watch
?feature=player_embedded&v=
qoE_L6tGHi0
Schematic illustration of the setup for electro-spun fibers having core/sheath structure. (a) The spinneret was manufactured from two coaxial capillaries, through
which healing agent (core) and polymer solution(sheath) were simultaneously ejected to form a continuous coaxial jet. Two different SEM images of healing
agent encapsulated fibrous structures; (b) beads on string and (c) smooth tube, respectively. Inset figure of Fig. (b) and (c) is schematic of corresponding
core/sheath structures, respectively. http://braungroup.beckman.illinois.edu/JeongHoPark.html
Production of bicomponent
fibers – core-sheath by
electrospinning
Alternative - Production of hollow fibers
Production of bicomponent
fibers – core-sheath by
electrospinning
http://www.hillsinc.net/images/meltblownfig1.jpg
http://www.mecc.co.jp/en/html/products/
spinneret/ultra_co-axial.html
Production of bicomponent
fibers – core-sheath by
electrospinning
http://www.spraybase.com/new-products/
Production of bicomponent
fibers – core-sheath by
electrospinning
http://www.intechopen.com/books/nanofibers/core-shell-nanofibers-nano-
channel-and-capsule-by-coaxial-electrospinning
Core-shell fibers with „more cores“ – multichannel electrospinning
http://www.electro-spinning.com/multi_spinnerets.html
http://www.intechopen.com/books/nanofibers/core-shell-nanofibers-nano-
channel-and-capsule-by-coaxial-electrospinning
http://www.arsenalmedical.com/technology/axiocore-drug-delivery-platform
http://www.arsenalmedical.com/sites/default/files/Fiber%20Society%202012.pdf
Production of bicomponent fibers – core-sheath by
electrospinning
Electrospinning from a slit
General problemConfirmation of coaxiality of electrostatically spun fibers.
Production of bicomponent fibers – core-sheath by
electrospinning
Electrospinning from a slit
http://www.intechopen.com/download/get/type/pdfs/id/8656
Production of bicomponent fibers – core-sheath by
electrospinning
MELT electrospinning
example
Production of bicomponent
fibers – side-by-side by
electrospinning
http://download.springer.com/
static/pdf/662/art%253A10.10
07%252Fs10853-014-8431-
9.pdf?auth66=1425896583_1
1fb565e8926b45d06a4ff9f92
5a1f19&ext=.pdf
http://www.intechopen.com/download/get/type/pdfs/id/8656
Production of bicomponent
fibers – side-by-side by
electrospinning
The scanning electron microscopy (SEM) image of the electrospun HSPET/PTT
nanofibers shown in the graphic indicates that the as-spun fibers have curly and
helically crimped fiber morphologies. The average fiber diameter of the HSPET/PTT
nanofiber is 800 nm, and the diameter of helix is about 1–1.5 μm, simultaneously the
thread pitch of the helical structure is only about 1.5 μm that the whole fiber present a
morphology of tight spring.
Production of bicomponent
fibers – side-by-side by
electrospinning
Porous nanofibers
Nanoporous electrospun PLA nanofibers from a
dichloromethane solution.
http://what-when-how.com/nanoscience-and-nanotechnology/polymer-nanofibers-prepared-by-electrospinning-nanotechnology/
AC electrospinning
Production of fibers (nanofibers) without any
collector
The difference of the electric potentials exists between the
creating fibers and fibers created before = virtual collector
AC electrospinning
29
DC – direct current AC – alternating
current
transformer
30
AC needleless collector-less electrospinning
method
Experimental set-up
Production of nanofibres
without any collector
0-30 kV
AC
50 Hzd = (10 - 30)mm
230 VRod spinning
electrode
transformer
10 mm
AC needleless collector-less electrospinning
method
Experimental set-up
Time
Voltage,
Current
+O
nset-počátek
+T
erm
ination
-ukončení
- On
se
t
-Term
ination
-m
iddle
pha
se
+ m
iddle
phase
Onset
termination
Physical principles
Nanofibrous “train“ serves as a counter
electrode
Electric
vind+
+ +++
-- ---
Virtual counter
electrode
Virtuální
protielektroda
t0 t0 + 0.005
s
Uroboros
eating its
own tail
34
10
mm
Physical principles
Nanofibrous “train“ serves as a counter
electrode
Virtual counter
electrode; collector
12 mm