42 KJEMI 6 2025 Katharina Zurbes Date: 10th of December PhD thesis: Exploring Seed-Mediated Growth of Gold Nanoparticles and their Sensitivity for Biosensing Trial lecture: Plasmonic colloidal self-assembly for diagnosis and monitoring of cancer Assessment Committee • First opponent: Professor Leonardo Scarabelli, University of Cantabria, Spain • Second opponent: Professor Tapan Kumar Sau, International Institute of Information Technology-Hyderabad, India • Chair of the committee: Associate Professor Nadia Shardt, Department of Chemical Engineering, NTNU Supervisors • Main supervisor: Associate Professor Sulalit Bandyopadhyay, Department of Chemical Engineering, NTNU • Co-supervisor: Professor Ethayaraja Mani, Indian Institute of Technology Madras, Chennai, India Summary of thesis Gold nanoparticles are extremely small structures with unique optical properties that make them promising for medical applications, such as detecting diseases at an early stage. The goal of this thesis was to understand how these particles grow and how their shape can be controlled, because shape strongly influences their performance in sensing applications. Zygimantas Gricius Date: 12th of May PhD thesis: Design of Pickering Emulsions for Photocatalytic Applications Trial lecture: Interfacial mass transfer mechanisms in Pickering emulsions: State-of-the-Art and Challenges Assessment Committee • First opponent: Associate Professor Nina Lock, Aarhus University, Denmark • Second opponent: Senior Research Scientist Wilhelm R. Glomm, SINTEF Industry, Norway • Chair of the committee: Associate Professor Brian A. Grimes, Department of Chemical Engineering, NTNU Supervisors • Main supervisor: Professor Gisle Øye, Department of Chemical Engineering, NTNU • Co-supervisor: Professor Magnus Rønning, Department of Chemical Engineering, NTNU Summary of thesis Modern wastewater is full of organic pollutants — from pesticides to pharmaceuticals — that are difficult to remove with traditional treatment methods. This PhD research addresses that challenge with a creative solution: using sunlight and carefully engineered oil droplets, stabilized by light- activated particles, to break down harmful chemicals in water. These droplets, known as photocatalytic Pickering emulsions, act like tiny chemical microreactors. They are stabilized by nanoparticles, such as titanium dioxide (TiO₂), that sit at the oil-water interface. There, they absorb sunlight and trigger reactions that break down harmful organic pollutants. The thesis explored how to fine-tune these emulsions to make them more effective, stable, and reusable: • Embedding TiO₂ into hydrogels created more robust droplets that could be reused without losing performance. • Coating TiO₂ particles with polymeric stabilizers like poloxamers helped resist changes in water chemistry but could slightly reduce cleaning efficiency. • Particle surface modifications using silane chemistry allowed better control over droplet formation and pollutant interaction. • Gold-doped titania particles improved light absorption and performance — especially under visible light — while also enhancing droplet stability. This thesis not only expands the science of photocatalytic emulsions but also kickstarts new ways of thinking about sustainable water treatment. It shows that combining photocatalysis with smart material design can overcome long-standing challenges in the field — offering a low-cost, reusable, and scalable approach to cleaning contaminated water.
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