Title Višeslojne polimerne nanoprevlake masnih kiselina na bakru umrežene ionizirajućim zračenjem Title (english) Multilayered polymer nano-coatings of fatty acids on copper cross-linked by ionizing radiation Author Margareta Postonjski Mentor Marijana Kraljić Roković (mentor)Mentor Katarina Marušić (komentor)Committee member Marijana Kraljić Roković (predsjednik povjerenstva)Committee member Helena Otmačić Ćurković (član povjerenstva)Committee member Katarina Marušić (član povjerenstva)Granter University of Zagreb Defense date and country 2024-02-13, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Svakodnevni tehnološki napredak omogućava razvoj novih metoda sinteze i karakterizacije materijala, što potiče znanstvenike da istražuju i razvijaju nove i funkcionalnije prevlake koje mogu zadovoljiti specifične potrebe različitih industrija te pri tome biti ekološki prihvatljivi.
U ovom radu ispitana su zaštitna svojstva prevlaka nastalih samoorganizacijom molekula (SAM-ovi) četiri masne kiseline na površini bakra koje su potom umrežene ionizirajućim gama zračenjem. Prevlake neumreženih SAM-ova u korozijskim uvjetima nisu dugotrajno postojane te se relativno brzo uklone s površine. Primjenom gama zračenja inicira se polimerizacija masnih kiselina čime se postiže stabilnija, homogenija i dugotrajnija prevlaka. U ovome radu ispitana su zaštitna svojstva jednostavnih i slojevitih umreženih samoorganiziranih slojeva četiriju masnih kiselina (Crot, C6, C18 i C22) nanošenih metodom uranjanja. Zaštitna svojstva nastalih ispitana su elektrokemijskim metodama (metoda Tafelove ekstrapolacije i elektrokemijska impedancijska spektroskopija-EIS) u otopini koja simulira atmosferske uvjete, a prevlake su dodatno karakterizirane metodom kontaktnog kuta i termogravimetrijskom analizom. Dobiveni rezultati elektrokemijskih ispitivanja su pokazali da od jednostavnih prevlaka C22 prevlake pružaju najbolja zaštitna svojstva, C18 nešto slabija, a C6 najslabija zaštitna svojstva dok prevlake od Crot kiseline stvaraju zaštitu sličnu C22 prevlaci. Ispitivanja na slojevitim prevlakama pokazala su nešto slabija zaštitna svojstva, te od svih ispitivanih prevlaka C22 prevlaka je pokazala najbolja zaštitna svojstva. Vrijednosti kontaktnih kutova određene goniometrijom kod jednoslojnih prevlaka ukazuju na hidrofobnost svih prevlaka osim C6 prevlake, dok su od slojevitih prevlaka jedino kombinacije C6-C18 također hidrofilne, a ostale dvije kombinacije imaju hidrofobna svojstva. Termogravimetrijska analiza pokazuje da se razgradnja jednostavnih prevlaka odvija u jednom stupnju te da maksimalna temperatura raste s porastom duljine lanca. Razgradnja u dva stupnja se javlja kod većine slojevitih prevlaka, uz prvi pad mase bliži temperaturi određenoj za kraću masnu kiselinu, što ukazuje na manju termičku stabilnost u odnosu na jednostavne prevlake C18 i C22.
Abstract (english) Everyday technological progress enables the development of new methods of material synthesis and characterization, which encourages scientists to research and develop new and more functional coatings that meet the specific needs of different industries while being environmentally friendly. In this work, we tested the protective properties of the coatings created by the self-assembly of molecules (SAMs) of four fatty acids on the surface of copper, which were then cross-linked by ionizing gamma radiation. The coatings of
non-cross-linked SAMs are not long-lasting under corrosive conditions and are removed relatively quickly from the surface. The applying gamma radiation initiates the polymerization of fatty acids, resulting in a more stable, homogeneous and long-lasting coating. In this work, the protective properties of simple and layered cross-linked SAMs of four fatty acids (Crot, C6, C18, and C22) were investigated. The protective properties were tested by electrochemical methods (Tafel extrapolation method and electrochemical impedance spectroscopy-EIS) in a solution simulating atmospheric conditions, and the coatings were additionally characterized by the contact angle method and thermogravimetric analysis.
The results of the electrochemical tests showed that of the simple coatings, the C22 coatings had the best, the C18 coatings the slightly weaker and the C6 coatings the weakest protective properties. The Crot coatings offered only slightly weaker protection compared to the C22 coatings. Tests with layered coatings showed slightly weaker protective properties, and of all the tested coatings the C22 coating showed the best protective properties.
The contact angle values determined by goniometry for single-layer coatings indicate the hydrophobicity of all coatings except the C6 coating, while of the layered coatings, only the C6-C18 combinations are also hydrophilic, and the other two combinations have hydrophobic properties. Thermogravimetric analysis shows that the decomposition of simple coatings takes place in one step and that the maximum temperature increases with the increase in chain length. Degradation in two stages occurs with most layered coatings, with the first drop in mass closer to the temperature determined for the shorter fatty acid, which indicates lower thermal stability compared to simple C18 and C22 coatings.
Keywords
polimerne nanoprevlake
SAM-ovi
gama zračenje
radijacijsko umrežavanje
bakar
masne kiseline
Keywords (english)
polymer nanocoatings
SAMs
gamma radiation
radiation cross-linking
copper
fatty acids
Language croatian URN:NBN urn:nbn:hr:149:352056 Project Number: IP-2020-02-4344 Study programme Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry Type of resource Text File origin Born digital Access conditions Embargoed access Terms of use Created on 2024-02-15 10:11:55
