Istraživanje adsorpcije organskih kiselina na metalnu površinu primjenom kvarc-kristalne mikrovage

undergraduate thesis

• Title (english): Application of electrochemical quartz crystal microbalance in study of organic acids adsorption on metallic surface
• Author: Martina Mumelaš
• Mentor: Helena Otmačić Ćurković (mentor)
• Committee member: Helena Otmačić Ćurković (predsjednik povjerenstva)
• Committee member: Marijana Kraljić Roković (član povjerenstva)
• Committee member: Zana Hajdari Gretić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2016-09-07, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Chemical Engineering in Material Development

Abstract

Samoorganizirajući monoslojevi (SAM) su tanki, uređeni filmovi koji nastaju spontano adsorpcijom organskih molekula na površinu supstrata iz kapljevite ili parne faze, nakon čega slijedi samoorganizacija alkilnih lanaca. Budući da se uobičajeno karakteriziraju završna svojstva nastalog tankog filma, glavni cilj ovog rada bio je pratiti proces njegova formiranja odnosno adsorpcije stearinske kiseline na bakrenu elektrodu pomoću elektrokemijske kvarc-kristalne mikrovage te ispitati utjecaj otapala i koncentracije molekula u otopini na proces adsorpcije. Za ispitivanja korištena je kvarc-kristalna mikrovaga s rezonantnom (osnovnom) frekvencijom ~9 MHz, osjetljiva na promjenu mase reda veličine nanograma. Ispitivana je adsorpcija stearinske kiseline u vodi (c (SK) = 5*10^(-4)M, 10^(-4)M) i etanolu (c (SK) = 10^(-4)M, 10^(-3)M, 10^(-2)M). Kao rezultat ispitivanja dobivene su ovisnosti promjena frekvencije titranja kvarca o vremenu izlaganja elektrode pojedinoj otopini stearinske kiseline. Na temelju dobivene rezultata procijenjeno je da li je na površinu bakrene elektrode vezan monosloj, dvosloj ili pak sloj micela. Time je dobiven uvid o načinu i vrsti vezanja organske kiseline na metalnu površinu u ovisnosti o koncentraciji stearinske kiseline i korištenom otapalu što je od velike važnosti za njihovu praktičnu primjenu.

Abstract (english)

Self-assembled monolayers (SAM) are thin and well ordered films which form spontaneously by adsorption of organic molecules on the substrate surface from liquid or vapour phase, followed by alkyl chain self-organization. Whereas mostly the final properties of SAMs are characterized, the main goal of this work was to follow formation of film through the stearic acid adsorption on the copper electrode by using the electrochemical quartz-crystal microbalance and to examine the influence of solvent and the stearic acid concentration in solution on the adsorption process. The quartz-crystal microbalance with resonant (basic) frequency ~9 MHz was used, which is sensitive to mass change in nanograms. Adsorption of stearic acid in water (c = 5*10^(-4)M, 10^(-4)M) and ethanol (c = 10^(-4)M, 10^(-3)M, 10^(-2)M) solutions was examined. As the result the dependence of frequency changes on time of electrode immersion in studied solutions was obtained from which it was possible to draw a conclusion whether monolayer, bilayer or micelles layer is formed on the copper electrode surface. Thereby, insight in adsorption mode dependence on solvent and stearic acid concentration was gained which is important for practical application of SAMs.

• Keywords: kvarc-kristalna mikrovaga; bakar; stearinska kiselina; samoorganizirajući monoslojevi
• Keywords (english): quartz-crystal microbalance; copper; stearic acid; self-assembled monolayers
• Language: croatian
• URN:NBN: urn:nbn:hr:149:692540
• Study programme: Title: Applied Chemistry - Undergraduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Advanced materials and technologies; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) primijenjene kemije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-02-02 09:19:00