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CNR – ISMACIstituto per lo Studio delle Macromolecole

Sede di Biellawww.bi.ismac.cnr.it

Electrospinning processand its application in the textile field

Electrospinning research group

A. Varesano G. Mazzuchetti

A. Aluigi

C. Vineis

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KnowKnow--howhow

•Fibres science

•Physical, chemical and microscopic textile materials characterization

•Modification of surface properties of fibres and textiles – finishing treatments

•New fibres from waste textile and agricultural products

•Handle, wear properties and comfort of textile

•Biotechnologies in the textile industry

•Technological processes: low temperature plasma (LTP), electrospinning, wet and melt spinning

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Electrospinning process

Polymer filaments using a electrostatic forceFormahls 1934-1944

Electrodes

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Filter media:Liquid filtrationGas filtrationMolecule filtration

Medical and Life Science:Natural extra-cellular matrixPorous membrane for skinTubular shapes for blood vessels and nerve regenerationThree dimensional scaffolds for bone and cartilage regenerationDrug delivery carrier Wound dressing

Other Areas:Electromagnetic interference shieldingLCD and photovoltaic devices Ultra -lightweight spacecraft materials

Application areas

25%

15%

60%

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Applications in textile fieldApplications in textile field

Sportswear

Leisure

•Thermal insulation

•Vapour resistance

•Lightness

•End use performance

•Comfort

•chemical and biological gas

•Anti vapour barriers

• Bacteria barrier

•Comfort

Protective cloths

Media filters

• High durability and easy filter cleaning• High efficiency• Trapping of tiny unfriendly particles

with diameter < 0,5 µµµµm

Nanofibres properties:

•Large surface-to-volume ratio

•High effective porosity

•Small pore size

•Low apparent density

•High surface cohesion

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Electrospinning device for polymer solutionCNR ISMAC Biella

Schematic of the electrospinning setup

High - voltage power supply: 0-30 kVMetering pump: 0.1-0.001 ml/hMetallic needle: 0.20-0.65 mmØCollector (rotanting) : 5.5 cmØ

Characteristics electrospinning device

Electric field

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Fundamental aspect electrospinning process

60 fps

4500 fps

Emisferical surface of the fluid at the tip of the capillary tube

REF > ST

Increasing the electric field intensity the emisferical surface elongates a conical shape –Taylor cone

When intensity electrostatic field attaints a critical value the repulsive electrostatic force REF overcomes the surface tension ST, the charged jet of the fluid is ejected from the Taylor cone tip

The polymers solution, during the course from the tip of the capillary tube to the collector, undergoes whipping process where the solvent evaporation occurs

5000x

Fluid-dynamic instability zone

Jet trajectory

Linear

Typical whip like motion

Electrospun nano-fibres web: a typical random distribution of the nano fibres on the collector

Electrospun mat: final product

Electrospinning parameters

System parameterSolution properties Molecular weight

Polymer architecture

Concentration

Conductivity

Surface tension

Process Parameters

Electrical potential at the capillary tip

Gap – distance between the tip and the collector

Flow rate of the polymer solution

Viscosity

Ambient conditions

Hydrostatic pressurein the capillary tube

TemperaturePressure

Fibres diametersFibres diameters Defects /BeadsDefects /Beads

electrical voltageelectrical voltage

gap gap –– electrodes distanceelectrodes distance

surface tensionsurface tension

polymers concentration polymers concentration

viscosity solutionviscosity solution

ParametersParameters

System and processes parameters: influence on fibres diameters and defects 1/2

Beads

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System and processes parameters: influence on fibres diameters, defects and morphology 2/2

Polymer molecular

weight

Droplet

Beads

Flow rate

Diameter

Beads

Solvent volatility

Nanofibres with pores

Droplets Beads

250 nm

Drops

100 nm

From Zheng-Ming Huang et al., Composite Science and Technology, 63 (2003), 2223-2253

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2

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Fibres diameter [nm] vs. Electrical Voltage [kV]

20000x

PEO/ Water, 5% p/pPEO/ Water, 5% p/p

15 15 kVkV, , 0.01 ml/min0.01 ml/min

nm

Diameters distribution

ddmm = 251 = 251 nmnm

20000x

PEO/ Water, 5% p/p,PEO/ Water, 5% p/p,

20 20 kVkV, , 0.01 ml/min0.01 ml/min

nm

Diameters distribution

ddmm = 190 = 190 nmnm

15000x

PEO/Water, 5% p/p,PEO/Water, 5% p/p,30 30 kVkV, , 0.01 ml/min0.01 ml/min

nm

Diameters distribution

d d mm= 172 = 172 nmnm

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Electrospinning device for polymer melt

Polypropylene electrospun condition:•T1: 230°C •T2: 280-290°C •T3: 100-140°C•T4: 85-95°C

Seungsin Lee et al. , Developing protective textile materials as barriers to liquid penetration using melt electrospinnig, Journal of applied polymer science, vol.102, 3340-3437 (2006)

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Filtration 1/3

Particles < 0.5 µµµµm

Coarse Particles

Particles > 0,5 µµµµm

Filtration Mechanisms

Mechanical separation

Inertial impact

Diffusion

AdsorptionNanofibres !Nanofibres !

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Filtration 2/3Electrospinning process:PEO nanofibre deposition

PET non-woven Air permeability: 2510 m/h

PET non-woven + nanofibres web

Cross-sectionFront viewFront view

Collector

PET non-woven

•Trapping of tiny unfriendly particles

with diameter < 0,5 µµµµm

•High efficiency

•High durability and easy filter cleaning

From F. Dotti, A. Varesano, A. Montarsolo, A. Aluigi, C. Tonin, G. Mazzuchetti, J. Ind. Textiles, 37, 2/ October 2007, 151-162

Performance request to filter media

Trapping of tiny unfriendly particles

with diameter < 0,5 µµµµm

Pz = f(d*t -1)Pz = pore sized = fibre diametert = exposition time

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Filtration 3/3

From L. Li, et al., J. Eng. Fibers Fabrics, 1(1) (2006).(Available on: http://www.jeffjournal.org)

Filtration efficiency is improved by nanofibre webs .Filtration efficiency increases as coverage level i ncreasesSimilar life with nanofiber filter and standard fil ter

PA6 nanofibres on cellulose-based air filter

High efficienty

930.0250.361Respirable>1 micron

920.0030.037Sub-micron

Cellulose +nanofibers

860.060.441Respirable>1 micron

680.010.031Sub-micron

Cellulose

Dust reduction%Inside dust

[mg/m3]Outside dust

[mg/m3]Filter

Use the nanofibers filter resulted 4 timesless penetration of sub-micron dust

From T.H. Grafe, K.M. Graham, Nonwovens in Filtration Fifth International Conference, Stuttgart (GER) 2003.

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Protective cloths 1/2

Air permeability: f(d*s-1)

Comfort

Good breathability

Good water vapour diffusion

Barrier performance

but

Barrier performance

Air permeability

Comfort

Goal High protection as well as an acceptable level of comfort

From F. Dotti, A. Varesano, A. Montarsolo, A. Aluigi, C. Tonin, G. Mazzuchetti, J. Ind. Textiles, 37, 2/ October 2007, 151-162

PET non-woven

Air permeability: 2510 m/h

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Nonwoven + microporous membraneNonwoven + electrospun membrane

Protective cloths 2/2

020406080

100120140160180

94 95 96 97 98 99 100

Protection %

Air

perm

eabi

ty [c

m3 /s

/cm

2 ]

microporousmembrane

electrospunmembrane

woven workcloth

Electrospun membrane:

A good compromise among protection and comfort

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Problems connected to electrospinning application in textile field

Productivity:

multi jet solution?

other systems ?

Electrospinning feeding:

from polymer solution ?

from polymer melt ?

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Productivity 1/3

Multi jet device

Mono jet: from 10 µµµµl/min to 10 ml/min

Multi jet* : from 22.5 µµµµl/cm 2min to 22.5 ml/cm 2min

*inter capillary distance: 1 cmdensity: 2 capillaries/cm2

Jets pushed away from their neighbours by Coulombicforces applied from the latter

From S.A. Theron et al., Multiple jets in electrospinning: experiment and modelling, Polymer, 46, (2005) 2889-2899

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Productivity 2/3

a = layer of magnetic liquid ; b = layer of polymeric solution; c e d = counter electrode located at a

distance H;e = high voltage source; f = electromagnet

Needleless electrospinning

From A.L.Yarin et al., Upward needless electrospinning of multiple nanofibres, Polymer, 45 (2004), 2977-2980

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Productivity 3/3

Needleless electrospinning:Elmarco Nanospider®

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Electrospinnig feed

From polymer solution

•Problems connected to removal and to recycling of organic solvents.

•No difficult in the capillaries cleaning

•Greater environmental impact respect to electrospinng from polymer melt

From polymer melt

•Problems connected to thermal control of process room and to high viscosity of polymer melt

•Problems connected to cleaning of the capillaries

•No solvent use

•Possibility to produce nanofibres of polymers as polyethylene, polypropylene and polyester

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Electrospinning research activities on the textile field

Process

Feedingsystem

Product

Collectors for electrospun

fibres

Cross-linking nanofibre web

on textile support

Physical and

Mechanical

performance

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Bibliography• 1. M. Ming Huang et al., A rewiew on polymer nanofibers by electrospinning and their application in

nanocomposites, Composites Science and Technology, 63, 2003• 2. A. Montarsolo et al., Potenzialità e Applicazioni delle Nanofibre prodotte mediante Elettrofilatura

per l’Innovazione Tessile, Convegno NanoItaltex Milano 12 luglio 2005 • 3. G. Mazzuchetti et al, Relazione finale Progetto LATT, Regione Piemonte 2005• 4. A. Aluigi ed altri, Elettrofilatura per la produzione di nanofibre, Nanotec IT newsletter, giugno

2005l.5. G. Mazzuchetti et ai, Il processo di elettrofilatura per la produzione di nanofibre, Convegno Moda e Tecnologia, 29-30 settembre Padova

• 5. Defil, La filtrazione dell’aria, www.defil.it• 6. F. Dotti et al. Electrospun porous mats for air/gas filtration, Journal of industrial textiles, 37, 2007,

151-162• 7.Seungsin Lee et al. , Developing protective textile materials as barriers to liquid penetration using

melt electrospinnig, Journal of applied polymer science, vol.102, 3340-3437 (2006) • 8. S.A. Theron ed altri, Multiple jets in electrospinning: experiment and modelling, Polymer, 46,

(2005) 2889-2899• 9. W. Tomaszewski et al., Investigation of electrospinning with use of a multi-jet electrospinning

head, Fibres & Textiles in Eastern Europe, October/December 2005, Vol.13 n. 4(52), 22-26• 10. A.L.Yarin et al., Upward needless electrospinning of multiple nanofibres, Polymer, 45 (2004),

2977-2980• 11. Elmarco, Brochure presentazione Sistema Nanospide®• 12. A. Varesano et al., Electrospinning and nanofibres in textile application, Nanonforum 2007,

Milan September 18-19th• 13. L. Li, et al., J. Eng. Fibers Fabrics, 1(1) (2006).• 14 T.H. Grafe, K.M. Graham, Nonwovens in Filtration Fifth International Conference, Stuttgart

(GER) 2003.

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Thank you very much for your attentionThank you very much for your attention

CONSIGLIO NAZIONALE DELLE RICERCHE

ISTITUTO PER LO STUDIO DELLE MACROMOLECOLE

Sede di BIELLA

C.so G. Pella 16, 13900 BiellaTel. +39-15-8493043 - Fax +39-15-8408387

e-mail: segreteria@bi.ismac.cnr.it

http://www.bi.ismac.cnr.it