Stabilnost i kinetika agregacije nanočestica TiO2

master's thesis

• Title (english): Stability and kinetics of TiO2 nanoparticle aggregation
• Author: Silvia-Maria Franov
• Mentor: Davor Kovačević (mentor)
• Committee member: Davor Kovačević (predsjednik povjerenstva)
• Committee member: Željka Soldin (član povjerenstva)
• Committee member: Ivan Nemet (član povjerenstva)
• Committee member: Tajana Begović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2023-07-13, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

U sklopu ovog rada istražena su fizikalno-kemijska svojstva nanočestica titanijeva dioksida
(TiO2), suspendiranih u vodenim otopinama elektrolita i polielektrolita. Dinamičkim
raspršenjem svijetlosti i mikroelektroforezom određeni su hidrodinamički promjer i
elektrokinetički potencijal čestica kao pokazatelji stabilnosti suspenzija. Istraživanje se
fokusiralo na utjecaj promjene pH–vrijednosti, ionske jakosti, vrste i koncentracije soli te
polielektrolita na stabilnost nanočestica (nanopločica i nanosfera) u suspenziji. Ispitano je kako
modifikacija površinskog naboja pozitivno ili negativno nabijenim polielektrolitom utječe na
stabilnost suspenzije uz dodatak soli jednovalentnih kationa. Procijenjena je učinkovitost
polielektrolita kao potencijalnih stabilizatora nanočestica TiO2 u kontekstu kinetike agregacije
čestica. Pokazano je za obje morfologije da uslijed prenabijanja površine nanočestica
polielektrolitom, priređeni sustavi pokazuju izuzetnu stabilnost te da ne dolazi do agregacije u
području izoelektrične točke. Također, ustanovljeno je da je potrebna viša koncentracija soli za
agregaciju nanočestica ukoliko je polielektrolit adsorbiran na površinu čestica.

Abstract (english)

In this study the physicochemical properties of titanium dioxide (TiO2) nanoparticles suspended
in electrolyte and polyelectrolyte aqueous solutions were investigated The hydrodynamic
diameter and the electrokinetic potential of the particles, as indicators of suspension stability,
were measured using dynamic light scattering and microelectrophoresis. The research focused
on the influence of changes in pH, ionic strength, type/concentration of salts and
polyelectrolytes on the stability of nanoparticles (nanoplates and nanospheres) in suspension. It
was examined how surface modification with either positively or negatively charged
polyelectrolyte affects suspension stability in the presence of monovalent salts. The efficacy of
polyelectrolytes as potential stabilizers for nanoparticles, in the context of particle aggregation
kinetics, was assessed. It was shown that due to the surface overcharging by the
polyelectrolytes, the prepared systems showed exceptional stability, with no aggregation near
the isoelectric point. Additionally, it was found that a higher salt concentration is required for
nanoparticles aggregation if the polyelectrolyte is adsorbed on the particle surface.

• Keywords: dinamičko raspršenje svijetlosti; elektroforetsko raspršenje svjetlosti; kinetika agregacije; polielektroliti; nanočestice; titanijev dioksid
• Keywords (english): dynamic light scattering; electrophoretic light scattering; aggregation kinetics; polyelectrolytes; nanoparticles; titanium dioxide
• Language: croatian
• URN:NBN: urn:nbn:hr:217:038324
• Project: Number: IP-2020-02-9571; Title: Fizikalna kemija procesa na međupovršini mineral/otopina (poli)elektrolita; Title: Physical chemistry of processes at mineral/(poly)electrolyte solution interface; Acronym: POLYMIN2; Leader: Tajana Begović; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Graduate university studies in chemistry; specializations in: Research programme; Course: Research programme; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra kemije (magistar/magistra kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2025-07-13
• Created on: 2023-07-19 10:39:33