Nanofibers,Nanofibers, technologytechnology andand applicationsapplications
OldOldřřichich JIRSÁKJIRSÁK TechnicalNanofibres NanofibresUniversity of Liberec, Czech Republic
What is electrospinning? Electrospinning is the process using electrostatic forces to form a fine filament of the polymer solution.
What is nanofiber? Fiber with diameter in nanometer range. Many types of polymers were processed into nanofibers of 50 to 1000 nanometers in diameter, several orders of magnitude smaller than conventional fiber spinning. Technical University of Liberec, Czech Republic
NANOFIBERS
Properties large specific surface area high porosity small pore size diameter range (50 – 1000) nm Material Polymer solutions or melts More than 30 polymers, including polyethylene oxide, DNA, polyaramids, and polyaniline, have been electrospun. These fibers can be made of variety organic (nylon, polyester, acryl) or biological polymers (proteins, collagens). PVA, PS, PAN, but also peptide amphiphiles or cellulose. Technical University of Liberec, Czech Republic
Technology of nanofibers – Electrospinning technology
0.1 - 1gramms per hour
In the electrospinning process a high voltage is used to create an electrically charged stream of polymer solution or melt. A high voltage electrode is linked with the polymer solution. The solution is then spun through a capillary. Due to high voltage electric field between the tip of capillary and a grounded collector, Taylor cone is formed at the tip of capillary producing sub-micron in diameter fibres. Fibres solidify as the polymer solvent evaporates and create an interlinked fiber layer on the surface of the collector. NN AA NN OO SS PP II DD EE RR
NANOFIBRESNANOFIBRES APPLICATIONSAPPLICATIONS • Air and liquid filters • Wound dressings • Tissue enginnering • Surface modifications • Sound absorptive materials • -etc AirAir filtration filtration properties properties ofof various various materials materials
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70 meltblown
60 charged meltblown
50 glass microfibers
Efficiency (%) 40 needle punch
30 PA6 nanospider
20 PA6/PU nanospider 10 0 50 100 150 200 250 300 350 400 450 500 Pressure drop (Pa) WoundWound dressings dressings NanofibersNanofibers WoundWound dressings dressings - - functions functions FunctionFunction ofof woundwound dressingdressing SoundSound absorptive absorptive materials materials
Profile : Nanofibrous layer is applied by the electro spinningproces to the basic fibrous material SoundSound absorption absorption - - nanofibres nanofibres
Basic fibrous material with the nanofibrous layers of different area densities (colored curves) vs. 1 Basic material without the nanofibers(black curve)
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0,6 α 0,4
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0 100 1000 10000 f [Hz] basic material nano-1 g.m-2 nano-0,5 g.m-2 nano-0,1 g.m-2 ThanksThanks for for Your Your Attention Attention