1

Physical principles of nanofiber production

11. liquid jet

D.Lukáš

2010

2

Xiao-Hong Quin & col

Donghua University, Shanghai, China

Effect of LiCl on electrospinning of PAN polymer solution:

theoretical analysis and experimental verification

Polymer, www.elsevier.com/locate/polymer

Reference:

3

ru

+

+

+

+

+

+

+

+

Surface density of the charge

Liquid density

Qur 2

Volume flow rate

IErkru 22

Dimensionless conductivity

El. current

Applied electric field

Surface Bulk

z

1,0

EzE

4

Bernoulli equation .2

1 2 consgzpu

gdz

d

rr

E

dz

dpu

dz

d

2

2 121

2

Viscous forceElectrostatic surface force

r

Eu

dz

d

2

2

2

E

5

Scaling and dimensionless analysis

02 rQur 022 rIErkru

r

Eu

dz

d

2

2

2

mass

current

energy Allometric relation

2/1 , rEr

/134 rrdz

d

2 ru

6

/134 rrdz

d mzzrr )(

Nonlinear differential equation

m=?

dzrdzrdz

d /134

1)/13()/13(4

1)/13(

1

mmm z

mdzzz

1)/13(4 mm)1/( zr1)/11(0 m

1/m

7

)1/( zr

IErkru 22

2/11 zr

2/10

zrrru

+

+

+

+

+

+

+

+

z

8

9

10

11

12

Whipping part of the jet

13

a b

Figure 4.4. Loops in unstable region of jet, caught on a slide glass -(a) PVA jet, (b) PEO jet.

14

Figure 4.6. Schematic diagram showing the Pendulum mechanism: (1) ground collector, (2) pendulum and (3) spinning electrode with a polymer.

15

a b

Figure 4.5. Instability of Polyethylene-oxide jet - Exposed with two various exposure times of 1 ms and 18 ns.