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Textiles 1

  2. 2. INTRODUCTION<br /><ul><li>nanos (greek) means dwarf
  3. 3. technologies dealing with structures less than 100 nm
  4. 4. 1 nm is a trillionth of 1 m (10-9m)
  5. 5. surface properties play a more important role compared to
  6. 6. the volume properties - therefore:
  7. 7. Richard Phillips Feynman “There is plenty of room at the
  8. 8. Bottom” is considered to be the “father” of nanotechnolgy
  9. 9. interdisciplinary interaction of sciences (physics, chemistry)
  10. 10. therefore nanotechnology is called a convergent technology
  11. 11. nano materials are already of significance today</li></li></ul><li>Nano Products Available in the Market<br /><ul><li>pigments (most important)
  12. 12. up-to-date computer chips (nano lithography)
  13. 13. surface functionalisation with nano layers or composites</li></ul>“self-cleaning” surfaces (“lotus-leaf effect”)<br /><ul><li>optically functional surfaces for antireflective coatings of displays</li></ul> (“moth-eye effect”)<br /><ul><li>chemical nano-products already exist for a long time:</li></ul>like TiO2 or ZnOnanoparticles in sunscreens<br /><ul><li>textile research focuses on new functional properties:</li></ul>soil-repellence, UV-protection, abrasion resistance, drug delivery...<br />
  14. 14. SOME APPLICATIONS OF NANOTECHNOLOGY IN TEXTILES<br />1) Ag (antimicrobial activity)<br />2) SiO2 (sol-gel, ceramic layers)<br />3) TiO2 (UV-protection, photocatalysis)<br />4) bionics: shark-skin effect, self-cleaning surfaces<br />
  15. 15. FUNCTIONAL/INTELLIGENT MATERIALS<br />functional materials<br /> (on the market)<br /><ul><li> waterproof, wind-</li></ul> tight, breathable,<br /> humidity transport<br /> etc.<br /><ul><li> optimized material</li></ul> properties<br /> e.g. color fastness,<br /> tensile and abrasion<br /> resistance, heat-<br /> proof, cold-resistant<br />intelligent materials<br /> (under development)<br /><ul><li> developments with</li></ul> new raw materials<br /><ul><li> development with</li></ul> additional electronic<br /> functions<br />smart materials<br /> (in the market)<br /><ul><li>smell release or</li></ul> odor control<br /><ul><li>advanced wearing</li></ul> comfort and heat<br /> insulation<br /><ul><li>individually</li></ul> adjustable heat<br /> insulation<br /><ul><li>microcapsules with</li></ul> phase change<br /> materials (PCM)<br /><ul><li>reflection materials
  16. 16. EM field protection
  17. 17. UV protection</li></li></ul><li>Antimicrobial Fiber Modification(biochemical effect with nano silver)<br />antimicrobial body wear<br /><ul><li> caused by increasing customer</li></ul> awareness of hygiene<br /><ul><li> odor control
  18. 18. medical applications
  19. 19. silver nanoparticles in the fiber
  20. 20. silver nano coating
  21. 21. high washing fastness
  22. 22. done by electrospinning</li></ul>Micro fiber<br /> silver coating<br />braced silver<br />coating on the<br />fiber surface<br />microfiber<br />cross section<br />
  23. 23. Ceramic Coating (Sol-Gel-Process)<br /><ul><li> matrix-precursor (SiO2 nanoparticles with cross-linking silicium organic compounds)
  24. 24. functional additives</li></ul>- solvent<br />Temp.<br />Lyogel<br />Sol<br />Xerogel<br />textile<br />Properties:<br />mechanical: reinforcing, scratch-resistant, antistatic, anti-adhesive<br />optical: interference colors, UV protection, IR absorption<br />biological: antimicrobial, medical applications<br />
  25. 25. How to improve the UPF of Textiles<br />(ultraviolet protection factor)<br />+ fabric design<br />+ tighter weaving or knitting<br />+ higher weight<br />+ textile finishing<br />+ organic dyes absorbing UV light<br />+ optical brighteners (in detergents)<br />+ dark coloration<br />+ fiber modification<br />+ TiO2, ZnOnano pigments for dulling of chemical fibers<br />+ coating is essential to prevent photocatalytic reactions<br />
  26. 26. Fiber Raw Materials and UV Protection<br />Polyester (PET, PPT, PBT)<br />+ terephthalic acid absorbs in the spectral UV range<br />+ protection is increased by additional dulling (µ/n-TiO2)<br />+ best protection possible<br />Polyamide (PA 6, PA 6,6) - nylon<br />+ only „full dull“ types provide good protection<br />natural fibers (cotton, wool, linen)) & regen. cellulose fibers (CV, CLY)<br />+ little to no protection at all (especially when wet)<br />+ full dull viscose (TiO2) was available a few years ago<br />
  27. 27. Application of nano TiO2 on Fibers<br />PA uncoated<br />PA 2 % nano-TiO2 coating<br />
  28. 28. UPF after nano TiO2 Coating<br />UPF Rating according to AS/NZS 4399:1996<br />60<br /> 50<br />50<br />40<br /> 35<br /> 30<br />30<br /> 25<br />20<br /> 10<br />10<br /> 5<br /> 0<br />UPF (2 % Nano-TiO2)<br />UPF<br />UPF (uncoated)<br />CO (100 %) 142 g/m2<br />PES/CO (50/50) 125 g/m2<br />PA (100 %) 97 g/m2<br />
  29. 29. Photocatalytic Degradation of Matter<br />with TiO2 (Anatase Crystal-Modification)<br />+ photocatalytic TiO2 nanoparticles in anatase crystal<br />modification in presence with UV-radiation, water and<br />oxygen generate free radicals<br />+ radicals destroy organic substances<br />+ catalytic process, therefore large and free accessible<br />surface area (e.g. nano) is required<br />
  30. 30. Photocatalysis<br />When a semiconductor material is illuminated with ultra band gap light it becomes a powerful redox catalyst capable of killing bacteria, cleaning water, and even splitting water to give hydrogen and oxygen.<br />
  31. 31. When photocatalyst titanium dioxide (TiO2) absorbs Ultraviolet (UV)* radiation from sunlight or illuminated light source (fluorescent lamps), it will produce pairs of electrons and holes. The electron of the valence band of titanium dioxide becomes excited when illuminated by light. The excess energy of this excited electron promoted the electron to the conduction band of titanium dioxide therefore creating the negative-electron (e-) and positive-hole (h+) pair. This stage is referred as the semiconductor's 'photo-excitation' state. The energy difference between the valence band and the conduction band is known as the 'Band Gap'. Wavelength of the light necessary for photo-excitation is: 1240 (Planck's constant, h) / 3.2 ev (band gap energy) = 388 nm<br />The positive-hole of titanium dioxide breaks apart the water molecule to form hydrogen gas and hydroxyl radical. The negative-electron reacts with oxygen molecule to form super oxide anion. This cycle continues when light is available.<br />
  32. 32. Fiber Degradation (SEM Image of Polyamide)<br />
  33. 33. Nature as the Role Model:<br />Shark Skin with minimized Flow Resistance<br />source:<br />
  34. 34. Bionics: Swimmsuits with Shark-Skin-Effect<br />+ different friction<br />coefficients on the fabric<br />(knitted or printed)<br />+ creation of micro vortices<br />
  35. 35. Soil Repellence (Lotus Effect®)<br />+ nature as the role model (“bionics”)<br />+ combination of micro- and nanostructures with low<br />surface energy generated by wax crystals<br />+ such high performance is not achieved by common<br />fluorocarbon finish<br />+ water, oil and dirt simply roll off<br />+ but: structures are sensitive to mechanical stress<br />(scratching, abrasion, washing)<br />+ effect is lost if structures are damaged<br />+ nature can re-grow these structures - but textiles not (yet)<br />
  36. 36. Self-Cleaning Process in Nature (1)<br />hydrophobic surface<br />hydrophilic surface<br />
  37. 37. Self-Cleaning Process in Nature (2)<br />nanostructure<br />for small particles<br />microstructure<br />for larger particles<br />
  38. 38. Self-Cleaning on Plants (Spiraea)<br />
  39. 39. Self-Cleaning on Insects (Rose Beetle)<br />species 1<br />species 2<br />
  40. 40. Self-Cleaning on Insects (Housefly)<br />
  41. 41. Self-Cleaning on Plants (Lotus Leaf)<br />source: Schoeller Textiles<br />self-cleaning textile coating<br />with nanostructured surface<br />folien/xxx.ppt/aj Folien Nr. 37; 25.11.2005 © Hohensteiner Institute<br />SEM image (top) and<br />AFM surface topography of a lotus leaf<br />
  42. 42.
  43. 43.
  44. 44. Other Advancements<br />
  45. 45.
  46. 46.
  47. 47. Other Applications<br />SMART TEXTILES<br />Woven optical<br />Woven or<br />Woven or Printed<br />fibers ( screen )<br />printed Bus<br />Electrodes<br />Circuit on<br />Organza<br />Silk Organza<br />Embroided<br />( Silk + Gold )<br />NRIKeypad<br />
  48. 48. References<br />Beringer, Dr. Jan (2005). Nanotechnology in Textile Finishing. State of the Art and future Prospects. HohensteinInsitutes.<br />McLaughlin, James (2004). Nanotechnology & Its Applications in Textiles. University of Ulster.<br />Sawhney, P.,Singh, K., Codon, B., Sachinvala, N., and David Hui. Nanotochnology in Modern Textiles<br />http://www.mchnanosolutions.com/mechanism.html<br />