Different approaches for surface modifications : formation of inhibitive film on copper surfaces and surfaces functionalised with Ag nanoparticles

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Faculty of Chemistry and Materials Sciences | Doctoral thesis (article-based)
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Date
2008-03-28
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Mcode
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Language
en
Pages
54, [32]
Series
TKK dissertations, 105
Abstract
The purpose of this study was to investigate different surface modifications and two different approaches have been studied in this Thesis. In the first part, the purpose was to study the mechanism for the formation of inhibitive copper-benzotriazole [Cu(I)-BTA] film and in the second part, the surface modifications were done with Ag nanoparticles to create for example antibacterial surfaces. The formation of an inhibitive [Cu(I)-BTA] film on copper and copper alloy surfaces has been investigated as a function of potential, alloying element and oxygen content in the surrounding environment. Measurements were performed using scanning electrochemical microscope (SECM) with which the change from a conductive to an insulating surface can be detected. The potential of copper substrate was observed to have a crucial effect on the formation of inhibitive [Cu(I)-BTA] film. At positive potentials (from โˆ’0.2 V to open circuit potential) the formation of the film can be detected as a function of exposure time for benzotriazole (BTAH). At negative potentials the copper surface stayed conductive even after four hours exposure leading to a conclusion that no inhibitive film can form on the surface. This leads to a final conclusion that adsorption is not enough for the inhibition of copper. Also, the effect of alloying elements (in this study silver and phosphorus) was observed. Both of these elements decreased the rate of film formation and in the case of silver enrichment on the surface, film formation was totally absent. Moreover, the role of oxygen in the film formation was studied in this thesis and it was observed that oxygen is needed for the formation of inhibitive film on copper surface. In addition, surface modifications with Ag nanoparticles โ€“ which possess interesting properties like antibacteriality and Surface-Enhanced Raman Scattering (SERS) โ€“ have been studied. When Ag nanoparticles are embedded into the sol-gel films it was observed that their presence increased the barrier properties of the film. Furthermore, the stability of the films was able to be improved by low temperature O2 and H2 plasma treatments. A novel route for the formation of ultra-thin films with attached Ag nanoparticles is outlined in this Thesis. Ultra-thin films do not show antibacterial properties, inducing that attached nanoparticles are not antibacterial in the tested system but sufficient amount of dissolution of silver is needed. This study also questions the currently widely used testing methods. SERS activity of the ultra-thin films is not observed but with a slight modification in synthesis to create thicker films containing more Ag on the surface produces good SERS enhancement. The enhancement factor is 1ยท107 which is a relatively high value when thinking of practical applications as a SERS probe.

Tรคssรค vรคitรถskirjassa on tutkittu erilaisia lรคhestymistapoja pintojen muokkaukseen. Ensimmรคisen osan tavoitteena on ollut selvittรครค suojaavan kupari-bentsotriatsolikerroksen [Cu(I)-BTA] muodostumismekanismia ja toisen osan tavoite on ollut tutkia pintojen muokkausta Ag nanopartikkeleilla lรคhinnรค niiden antibakteeristen ominaisuuksien takia.Suojaavan [Cu(I)-BTA]-kerroksen muodostumista tutkittiin kuparin ja kupariseosten pinnalle potentiaalin, kupariseokseen lisรคttรคvรคn alkuaineen tai ympรคristรถn happipitoisuuden funktiona. Pintoja tutkittiin sรคhkรถkemiallisella pyyhkรคisymikroskoopilla (SECM), jonka avulla voidaan tutkia johtavan pinnan muuttumista eristรคvรคksi pinnaksi. Kuparin potentiaali vaikuttaa suojaavan [Cu(I)-BTA]-kerroksen muodostumiseen. Positiivisilla potentiaaleilla (-0.2 V:sta avoimen virtapiirin potentiaaliin) kerroksen muodostuminen tapahtui bentsotriatsolin (BTAH) altistusajan funktiona; negatiivisilla potentiaaleilla suojaavaa kerrosta ei havaittu edes neljรคn tunnin altistusajan jรคlkeen eli suojaavaa kerrosta ei muodostu pinnalle. Tรคstรค voidaan pรครคtellรค ettรค pelkkรค BTAH:n adsorptio ei ole riittรคvรค suojaamaan kuparipintaa. Myรถs kupariseokseen lisรคttรคvรคt alkuaineet (fosfori ja hopea) hidastivat suojaavan kerroksen muodostumista. Hopea esti kokonaan kerroksen muodostumisen suurilla hopeapitoisuuksilla. Hapen lรคsnรคolo todettiin vรคlttรคmรคttรถmรคksi suojaavan kerroksen muodostumisessa.Lisรคksi tรคssรค tyรถssรค tutkittiin pintojen muokkausta Ag nanopartikkeleilla, joilla on monia mielenkiintoisia ominaisuuksia kuten antibakteerisuus tai nk. SERS-aktiivisuus eli ne voivat vahvistaa Raman spektriรค moninkertaisesti. Kun Ag nanopartikkelit muodostettiin sol-gel-kerroksen sisรคlle, ne estivรคt paremmin liuoksen tunkeutumista kerroksen lรคpi. O2- ja H2 โ€“plasmakรคsittelyillรค sol-gel-kerrosten stabiilisuus kasvoi. Tรคssรค tyรถssรค esitellรครคn myรถs uusi tapa valmistaa hyvin ohuita Ag nanopartikkelikerroksia siten, ettรค nanopartikkelit ovat tiukasti pinnassa kiinni. Nรคmรค ohuet kerrokset eivรคt osoittaneet bakteerien kasvun hidastumista antibakteerisuuskokeissa eli tiukasti kiinnitetyt nanopartikkelit eivรคt itsessรครคn ole antibakteerisia tutkitussa systeemissรค, vaan hopean liukeneminen pinnalta on vรคlttรคmรคtรถn. Lisรคksi tรคssรค tyรถssรค kyseenalaistetaan tรคllรค hetkellรค runsaasti kรคytettyjen testimenetelmien sopivuutta vastaavankaltaisiin tilanteisiin. Ohuiden kalvojen SERS-aktiivisuutta ei myรถskรครคn havaittu, mutta pienellรค muutoksella synteesiprosessissa voitiin valmistaa paksumpia kalvoja, jotka sisรคltรคvรคt enemmรคn Ag nanopartikkeleita. Nรคmรค kerrokset ovat SERS-aktiivisia ja niiden SERS-vahvistuskerroin on jopa 1ยท107, joka on riittรคvรคn korkea arvo ajatellen kรคytรคnnรถn sovelluksia SERS-anturina.
Description
Keywords
copper, benzotriazole, stainless steel, Ag nanoparticles, antibacteriality, kupari, bentsotriatsoli, ruostumaton terรคs, Ag nanopartikkeli, antibakteerisuus
Other note
Parts
  • K. Mansikkamรคki, P. Ahonen, G. Fabricius, L. Murtomรคki, K. Kontturi, Inhibitive Effect of Benzotriazole on Copper Surfaces Studied by SECM, Journal of The Electrochemical Society 152 (2005) B12-B16. [article1.pdf] ยฉ 2005 The Electrochemical Society. By permission.
  • K. Mansikkamรคki, U. Haapanen, C. Johans, K. Kontturi, M. Valden, Adsorption of Benzotriazole on the Surface of Copper Alloys Studied by SECM and XPS, Journal of The Electrochemical Society 153 (2006) B311-B318. [article2.pdf] ยฉ 2006 The Electrochemical Society. By permission.
  • K. Mansikkamรคki, C. Johans, K. Kontturi, The Effect of Oxygen on the Inhibition of Copper Corrosion with Benzotriazole, Journal of The Electrochemical Society 153 (2006) B22-B24. [article3.pdf] ยฉ 2006 The Electrochemical Society. By permission.
  • K. Yliniemi, P. Ebbinghaus, P. Keil, K. Kontturi, G. Grundmeier, Chemical composition and barrier properties of Ag nanoparticle-containing solโ€“gel films in oxidizing and reducing low-temperature plasmas, Surface & Coatings Technology 201 (2007) 7865-7872. [article4.pdf] ยฉ 2007 Elsevier Science. By permission.
  • K. Yliniemi, M. Vahvaselkรค, Y. Van Ingelgem, K. Baert, B.P. Wilson, H. Terryn, K. Kontturi, The Formation and Characterisation of Ultra-Thin Films Containing Ag Nanoparticles, Journal of Materials Chemistry 18 (2008) 199-206. [article5.pdf] ยฉ 2008 Royal Society of Chemistry. By permission.
Citation
Permanent link to this item
https://urn.fi/urn:nbn:fi:tkk-011245