Njelama Sanga

What inspired you to pursue this research topic, and how has your understanding of it evolved throughout your PhD journey?

After completing my master’s degree in Nuclear Physics in Russia, I wanted to return to my physical chemistry roots, and this project caught my interest because of its use of neutron scattering and its focus on Per-and polyfluoroalkyl substances(PFAS) which are fluorinated organic molecules, which have been in the news due to their toxicity and persistence. My understanding of how these fluorinated surfactants behave in aqueous solutions and interact with relevant environmental materials has grown, and I now have clearer ideas about their characteristics and their role in the environment. As with any research topic, the knowledge continues to expand, and the learning and understanding never truly end.

Can you describe a key finding or insight from your research that you’re especially proud of and why it matters in your field?

PFAS are in the news daily, and Sweden, like many other countries, is spending billions of kronor to clean up these contaminants. We have developed an understanding of the characteristics of these fluorinated surfactants. The presence of counterions affects how they pack: as the counterion changes from Na⁺ to Mg²⁺, the aggregates become less curved and longer, meaning more surfactant molecules are incorporated into the assemblies. Changing temperatures and the concentration also influence aggregate length.

When fluorinated surfactants interact with environmentally relevant materials such as Moringa oleifera seed proteins, which contain albumins similar to blood serum albumins the proteins are able to associate with the surfactants. After rinsing, the surfactant detaches while the protein would usually remain bound to a support. Apart from providing a potential route to remediation, this is particularly interesting because it provides insight into how these surfactants may be transported in the body and ultimately deposited in the liver.

How do you hope your research will be used or built upon after your defense — whether in academia, industry, or society at large?

The results from my research suggest potential methods for cleaning up fluorinated surfactants in the environment. Seed proteins can be used to associate effectively with fluorinated surfactants in contaminated water. The bound surfactant can then be rinsed off and concentrated through evaporation or by precipitating it with a calcium salt, before undergoing further degradation through processes such as electrochemical oxidation, which leads to defluorination.

What role has SwedNess played in your journey?
SWEDNESS enabled me to do great science by giving me the opportunity to travel to neutron facilities I would otherwise never have had access to, such as the Rutherford Appleton Laboratory in the UK and the ILL in Grenoble, where I carried out my experiments. I also had the chance to meet neutron experts from a wide range of disciplines, and we have now become a wonderful community. I am grateful for the opportunity to travel to Japan, spend a week learning, and visit J-PARC an absolute highlight of my experience.

Thank you to Martin Månsson for always creating excellent learning opportunities for us students, and to Camilla Dann for the thoughtful planning and coordination. SWEDNESS opened doors for learning, networking, and forming lasting friendships. Thank you very much.

Thesis: Self-assembly of fluorocarbon amphiphiles and their interactions at interfaces with a seed protein