Electrospun Nanofiber

Membranes Membranes

Pierre Aimar

Laboratoire de Génie Chimique

Université de Toulouse and CNRS

1

Membrane preparation techniques

• Interfacial polymerization

• Track etching

• Stretching

• Etc….• Etc….

2

Research papers published in the Journal of

Membrane Science featuring “electrospinning”

20

25

30

0

5

10

15

20

1998 2000 2002 2004 2006 2008 2010 2012 2014

3

Electrospinning: What is this ?

Taken from Wikipedia – September 2nd, 20134

Electrospinning: conditions

• E= 50-500 kV/m

• Fiber dimensions: 20 to 500 nm

• Almost all types of polymers melts or in

solutionsolution

• Spinning rate: 40 m/s

• Mat porosity: 50 to 90 %

5

6

7

K. Yoon et al. / Journal of Membrane Science 338 (2009) 145–1528

“Electrospinning” and “Membranes” in

peer-reviewed literature

250

300

350

400

20

25

30

JMS

Total

0

50

100

150

200

0

5

10

15

1998 2000 2002 2004 2006 2008 2010 2012 2014

Doshi et al., Polym News, 1995, 20, 206-207.

9

Technical domains

• Filtration

• Affinity membranes

• Wound healing

• Controlled release• Controlled release

• Catalyst / enzyme immobilization

• Sensors

• Energy storage

10

Electrospun nanofibers in real life ?

• 4spin: lab scale electrospinning systems

• Fiberio: Lab and industrial scale electrospinningequipments

• Elmarco: Electrospinning industrial equipment

• Nanostatics : Commercialized 2 m large nanofibers mats –• Nanostatics : Commercialized 2 m large nanofibers mats –(still active ?)

• Dupont: Hybrid Membrane Tech (HMT®) – nylon fibers 600 nm

• Donaldson: Dust and aerosols industrial collectors –modules from 1 to 23 m2 (26 inch w) (Ultraweb® technology) (1st to introduce NFibers in industrial filters –1981)

Donaldson

11

Electrospun Nanofiber Membranes (ENM)

• Nanofiber mats have poor mechanical

properties per se ⇒

– Supporting layer needed: additional thickness and

transfer resistancetransfer resistance

– Post treatment

• Annealing (with or without mechanical compression)

• Solvent vapor percolation induce fiber fusion at their

contact points

Note: Post treatment : improves mechanical resistance and adjusts pore size

12

Post-treated ENM as membrane backbones

• Post treatment

– Functionalisation by Plasma

– Impregnation

– Co-extrusion and melting: proton exchange – Co-extrusion and melting: proton exchange

membranes

13

Potential applications of ENF in

Membrane Technology ?

• Liquid filtration

– Microfiltration

– Ultrafiltration

– Nanofiltration– Nanofiltration

• Membrane distillation

• Battery separators – lithium ion

• Proton exchange Membrane Fuel cells

• Forward osmosis (Engineered osmosis)

14

An example of ENM performance:

Y. Liao et al./Journal of Membrane Science 440 (2013) 77–87

15

Conclusion

• Electrospinning:

– Breakthrough or technological “bubble” ?

– Intrinsically superior to existing casting techniques

(phase inversion, stretching, etc…) ?(phase inversion, stretching, etc…) ?

• ENM: which perspective as

– filtration membranes ?

– backbones for dense membranes (FC / RO/ PV / GS)?

• Production quality control on a large scale ?

16

• Recommended reading: Electrospining: a

fascinating method for the preparation of

ultrathin fibers, A. Greiner and H. Wendorff, ultrathin fibers, A. Greiner and H. Wendorff,

Angew. Chem. Int. Ed., 2007, 46, 5670-5703

• Thank you

17