Lidé

Ing. Štěpán Potocký, Ph.D.

Všechny publikace

Treatment of polypropylene microfibers by atmospheric and low-pressure plasma – application to a reinforced cement composite containing recycled concrete

  • Autoři: Ďureje, J., Prošek, Z., Ing. Štěpán Potocký, Ph.D., Trejbal, J., Hlůžek, R.
  • Publikace: NMM 2022 Nano & Macro Mechanics. Praha: Czech Technical University in Prague, 2023. p. 22-26. Acta Polytechnica CTU Proceedings. vol. 40. ISSN 2336-5382. ISBN 978-80-01-07186-1.
  • Rok: 2023
  • DOI: 10.14311/APP.2023.40.0022
  • Odkaz: https://doi.org/10.14311/APP.2023.40.0022
  • Pracoviště: Katedra fyziky
  • Anotace:
    The effect of atmospheric and low-pressure plasma modification on polypropylene (PP) microfibers was examined. Mechanical changes on the microfiber surfaces were observed using scanning electron microscopy (SEM). Next, wettability was measured using the packedcell method. The fibers were applied into a cement matrix containing micro-milled recycled concrete. Test specimens were made and then the dynamic modulus of elasticity was continuously measured. After 28 days were made in the test specimens central notches to a depth of 14 mm. Finally, bending tests were performed. From the results, the fracture energy of the composite material was calculated. It was proven that low-pressure plasma modification as well as atmospheric plasma modification increases the wettability of PP fibers with water. Furthermore, it was found that samples containing plasma-modified microfibers have a higher fracture energy compared to the same samples with fibers without plasma modification. Conversely, plasma modification had no effect on the dynamic modulus of elasticity.

Coating Ti6Al4V implants with nanocrystalline diamond functionalized with BMP-7 promotes extracellular matrix mineralization in vitro and faster osseointegration in vivo

  • DOI: 10.1038/s41598-022-09183-z
  • Odkaz: https://doi.org/10.1038/s41598-022-09183-z
  • Pracoviště: Katedra fyziky
  • Anotace:
    The present study investigates the effect of an oxidized nanocrystalline diamond (O-NCD) coating functionalized with bone morphogenetic protein 7 (BMP-7) on human osteoblast maturation and extracellular matrix mineralization in vitro and on new bone formation in vivo. The chemical structure and the morphology of the NCD coating and the adhesion, thickness and morphology of the superimposed BMP-7 layer have also been assessed. The material analysis proved synthesis of a conformal diamond coating with a fine nanostructured morphology on the Ti6Al4V samples. The homogeneous nanostructured layer of BMP-7 on the NCD coating created by a physisorption method was confirmed by AFM. The osteogenic maturation of hFOB 1.19 cells in vitro was only slightly enhanced by the O-NCD coating alone without any increase in the mineralization of the matrix. Functionalization of the coating with BMP-7 resulted in more pronounced cell osteogenic maturation and increased extracellular matrix mineralization. Similar results were obtained in vivo from micro-CT and histological analyses of rabbit distal femurs with screws implanted for 4 or 12 weeks. While the O-NCD-coated implants alone promoted greater thickness of newly-formed bone in direct contact with the implant surface than the bare material, a further increase was induced by BMP-7. It can be therefore concluded that O-NCD coating functionalized with BMP-7 is a promising surface modification of metallic bone implants in order to improve their osseointegration.

Growth and properties of diamond films prepared on 4-inch substrates by cavity plasma systems

  • Autoři: Babčenko, O., Ing. Štěpán Potocký, Ph.D., Aubrechtová Dragounová, K., Szabó, O., Bergonzo, P., prof. RNDr. Bohuslav Rezek, Ph.D., Kromka, A.
  • Publikace: NANOCON Conference Proceedings - International Conference on Nanomaterials. Ostrava: TANGER, 2021. p. 86-92. ISSN 2694-930X. ISBN 978-80-87294-98-7.
  • Rok: 2021
  • DOI: 10.37904/nanocon.2020.3701
  • Odkaz: https://doi.org/10.37904/nanocon.2020.3701
  • Pracoviště: Katedra fyziky
  • Anotace:
    Two microwave (2.45 GHz) plasma systems with ellipsoidal and multimode clamshell cavity for diamond synthesis by chemical vapor deposition were compared. Both systems are capable of high pressure (up to 20 kPa) operation and high growth rates (several µm/h). It was shown that by using the multimode operation of the clamshell cavity system and specially design sample holder, it is possible to sustain a plasma in a cavity and reach good enough process reproducibility and diamond film quality over 4-inch substrates.

Microscopic study of multifunctional drug molecule adhesion to electronic biosensors coated with diamond and gold nanoparticles

  • Pracoviště: Katedra fyziky, Katedra elektrotechnologie
  • Anotace:
    The easy and fast detection of drug content and concentration levels is demanded in biological research as well as in clinical practice. Here we study on microscopic level how nanodiamonds and gold nanoparticles interact with a multifunctional drug molecule directly on a biosensor surface. The sensors are made of interdigitated Au electrodes coated by 5 nm hydrogenated or oxidized nanodiamonds and further combined with Au colloidal nanoparticles (size 20 nm) providing nanoscale composite (spacing 100 nm). Atomic force microscopy is employed to measure local tip-surface adhesion forces and surface topography. AFM adhesion maps show that the drug binds to all types of nanoparticles and the adhesion is also significantly influenced by the substrates on which the nanoparticles are deposited. Role of local AFM tip interaction with nanostructured surface is also discussed.

Plasma treatment impact on physical and chemical properties of polymeric fibers

  • Autoři: Hlůžek, R., Prošek, Z., Trejbal, J., Fládr, J., Ing. Štěpán Potocký, Ph.D.,
  • Publikace: NMM 2017 - Nano & Macro Mechanics 2017. Praha: Czech Technical University in Prague, 2017. p. 49-54. Acta Polytechnica CTU Proceedings. vol. 13. ISSN 2336-5382. ISBN 978-80-01-06346-0.
  • Rok: 2017
  • DOI: 10.14311/APP.2017.13.0049
  • Odkaz: https://doi.org/10.14311/APP.2017.13.0049
  • Pracoviště: Katedra fyziky
  • Anotace:
    Presented work focuses on chemical and physical properties of plasma modified polymeric macro-fibers. Polyethylene terephthalate (PET) and polypropylene (PP) fibers having approx. 300 µm in diameter were modified using cold oxygen plasma in order to achieve their surface changes needed for durable bond and adhesion with cement matrixes. A duration of plasma modification differed between 5 to 480 seconds, where an effect of the treatment was examined. Fiber surfaces chemical changes were researched via wettability measurement with demineralized water (the measurement was repeated immediately and after 1, 7 and 30 days to find out the changes stability). Physical changes were studied by means of weight balance (determination of weight loss) and tensile strength tests. It was found that wettability was enhanced significantly – up to two times, while mechanical properties of treated fibers decreased only slightly.

Za stránku zodpovídá: Ing. Mgr. Radovan Suk