<p> <a href="/tags/Nanofiber/" rel="tag">Nanofibers</a>,Nanofibers, technologytechnology andand applicationsapplications</p><p>OldOldřřichich JIRSÁKJIRSÁK TechnicalNanofibres NanofibresUniversity of Liberec, <a href="/tags/Czech_Republic/" rel="tag">Czech Republic</a></p><p>What is electrospinning? Electrospinning is the process using electrostatic forces to form a fine filament of the <a href="/tags/Polymer/" rel="tag">polymer</a> solution. </p><p>What is <a href="/tags/Nanofiber/" rel="tag">nanofiber</a>? Fiber with diameter in nanometer range. Many types of <a href="/tags/Polymer/" rel="tag">polymers</a> were processed into nanofibers of 50 to 1000 nanometers in diameter, several orders of magnitude smaller than conventional fiber <a href="/tags/Spinning_(polymers)/" rel="tag">spinning</a>. Technical University of Liberec, Czech Republic</p><p>NANOFIBERS</p><p>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 <a href="/tags/Polyethylene/" rel="tag">polyethylene</a> oxide, DNA, polyaramids, and polyaniline, have been electrospun. These fibers can be made of variety organic (nylon, polyester, acryl) or biological polymers (proteins, <a href="/tags/Collagen/" rel="tag">collagens</a>). PVA, PS, PAN, but also peptide amphiphiles or cellulose. Technical University of Liberec, Czech Republic</p><p>Technology of nanofibers – Electrospinning technology</p><p>0.1 - 1gramms per hour </p><p>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 <a href="/tags/Solvent/" rel="tag">solvent</a> evaporates and create an interlinked fiber layer on the surface of the collector. NN AA NN OO SS PP II DD EE RR</p><p>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</p><p>100</p><p>90</p><p>80</p><p>70 meltblown</p><p>60 charged meltblown</p><p>50 glass microfibers</p><p>Efficiency (%) 40 needle punch</p><p>30 PA6 nanospider</p><p>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</p><p>Profile : Nanofibrous layer is applied by the electro spinningproces to the basic fibrous material SoundSound absorption absorption - - nanofibres nanofibres</p><p>Basic fibrous material with the nanofibrous layers of different area densities (colored curves) vs. 1 Basic material without the nanofibers(black curve)</p><p>0,8</p><p>0,6 α 0,4</p><p>0,2</p><p>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</p>