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