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Produce of Antibacterial Composite Coating of PTFE+Ag+TiO2 On 316SS and Study Its Properties

Sheikhzadeh, Mohammad Sajjad | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56437 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Afshar, Abdollah
  7. Abstract:
  8. This research investigated the corrosion and antibacterial properties of PTFE+TiO2/Ag coating and its adhesion to 316L stainless steel. To increase adhesion, polydopamine coating was created as an intermediate layer by chemical deposition method on stainless steel, then PTFE + TiO2 coating was created on the sample by immersion method, and then silver nanoparticles were applied as the third layer by chemical deposition method. According to the polarization curves, the most corrosion-resistant coatings with corrosion current density of 3.34×10-5 and 3.25×10-4 μA are coatings PTFE+TiO2 and PTFE/PTFE+TiO2/Ag respectively. In terms of antibacterial activity, according to the non-growth halo test, the PTFE+TiO2/Ag coating with 5% by weight of silver inhibits bacteria penetration by 37% compared to the positive control of kanamycin. As a result of its 143° angle of water contact, PTFE+TiO2/Ag is classified as a hydrophobic coating. In this experiment, polydopamine coating was applied to 316L stainless steel in three different conditions: temperature, time, stirring speed, and drying method, based on the nano scratch test, the most optimal coating was created at 60°C for one hour under 300rpm stirring and then dried for 24 hours in a freeze dryer. It appears that the coating's photocatalytic activity (Rs) is similar to the UV sensor's photocatalytic activity, which is measured from the current-time curve. The coating thickness is 1.2μm with an output speed of 1mm/s from PTFE+TiO2 emulsion and silver nanoparticle deposition for one hour. It is used on 316L orthopedic implants due to its low friction coefficient. This research combined PTFE nanoparticles, which are high in electrical insulation, with TiO2 because of its passivation properties, and blocked PTFE cavities in order to improve corrosion resistance of 316L orthopedic implants. Antibacterial properties of the coating are mainly provided by silver nanoparticles as the final coating. It can be applied in vivo by increasing the adhesion of the coating with polydopamine
  9. Keywords:
  10. Nanocomposite ; Hydrophobicity ; Corrosion ; Polytetrafluoroethylene(PTFE) ; Antibacterials ; 316 Austenitic Stainless Steel ; Nano-Composite Coating

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