Public defence in Engineering Physics, M.Sc. Lotta Gustavsson

Title of the thesis: Investigations of Ionic Functional Soft Matter

Doctoral student: Lotta Gustavsson
Opponent: Professor Charl Faul, University of Bristol, UK
Custos: Professor Olli Ikkala, Aalto University School of Science, Department of Applied Physics

Interactions between molecules and ions are crucial in the development of new materials. In this dissertation, ionic interactions were studied in different environments and harvested into functional materials.

In the first part of the dissertation, ion-based liquid crystals were studied. Liquid-crystalline phases arise from the fine balancing between different parts of the molecules. Here, suitable compositions of several different compounds were used to develop new liquid-crystalline materials that had emergent properties i.e., properties that the individual molecules did not possess. For example, new phases, different solubilities and emergence of ionic conductivity were noted. Such materials could be used as new type of electrolytes or polarizers in the future.

In the second part, so called smart materials, i.e., materials that respond to different stimuli or change in environment, were studied. Inspired by how humans can taste different types of molecules, an "artificial tongue" hydrogel was developed that could sense different types of molecules based on interactions between the tastant molecule and the hydrogel. In addition, also pH-responsive luminescent particles were developed that could be used in the bioimaging of certain cellular compartments. Finally, droplets that move as a response to changes in the electric field strength were studied. Controlling the movement of non-living objects could enable future applications in soft robotics and medicine.

Keywords: smart materials, molecular interactions, ions, liquid crystals, ion-conduction, electric field

Thesis available for public display 10 days prior to the defence at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/ 

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Doctoral theses in the School of Science: https://aaltodoc.aalto.fi/handle/123456789/52