26. August 2014 at 14 in Physicums aud A106 will defend Raul Välbe his doctoral theses in materials science "Developement of ionic liquid composites by sol-gel method for elaboration of industrial nano- and microstructures".
Dr. Ants Lõhmus, University of Tartu
Dr. Uno Mäeorg, University of Tartu
Dr. Valter Reedo, University of Tartu
Andres Hoop, Haine Paelavabrik OÜ
Dr. Karine Mougin, University of Haute-Alsace, France
Dr. Elvira Tarasova, Tallinn University of Technology
The main aim of this research was to develop methods for synthesizing solid ionic liquid - gel and oxide composites based on ionic liquids and metal alkoxides, and to clarify properties and applications of formed structures. The topic of the thesis - combining ionic liquids and sol-gel method to create functional composites - is a relatively novel research field and has been developing during last decade. Ionic liquids are chemically rather inert, thermally stable materials with ionic conductivity. This class of materials is highly popular because of the rather low production costs and the simplicity of synthesis methods, which induce extra competitive alternative for production of conductive and/or transparent electrolytes, nanoparticle synthesis, or functionalized textiles for different applications.
The main problem for creating alternative technologies for combining liquids into a solid is a fundamental contradiction between the liquid and solid mechanisms where improving one typically diminishes another. Nevertheless, materials' advantageous liquid state turns out to be an impediment for applications in devices which need stable solid state shaping. In addition, it is important for industry to find alternative materials and technologies for designing hybrid materials with unique properties.
In current thesis it was shown that some "green" ionic liquids hydrolyse already at the room temperature. Thereby novel hybrid dual-component crystals were discovered for the first time, which formed during the hydrolysis when in contact with other substances (e.g. glass, oxides, ceramics).
Special functionalized ionic liquid was synthesized to obtain solid homogeneous structures using sol gel method, by giving them curtain shape and size. Synthesized mixtures of ionic liquid and metal alkoxide were implemented in developing functionalized textiles. It was shown that cotton threads treated with ionogel have better breaking strencht, hydrophobic qualities, and wearproof compared to starting material.