Stimuli responsive hybrid microgels functionalized with metal nanoparticles
- Stimuli-responsive Hybrid Mikrogele funktionalisiert mit Metall-Nanopartikeln
Palchyk, Volodymyr; Pich, Andrij (Thesis advisor); Rueping, Magnus (Thesis advisor)
Dissertation / PhD Thesis
Dissertation, RWTH Aachen University, 2016
This dissertation deals with the synthesis and modification (in a direct or an indirect way) of microgels, which can act as containers for metal ions or nanoparticles. The first part of the work focuses on the synthesis of new catalytic colloidal reactors. The challenge was to combine the advantages of the homogeneous and heterogeneous catalysis and create hybrid microgels with defined properties. For this the application of the thermo-sensitive hybrid microgels, loaded with catalytic active centers was used. At the reaction temperature, hybrid microgels have a big surface area, are well dispersed and swollen in the solvent. Each catalytic active center was open and accessible for the reactants (advantage of the homogeneous catalysis). After the catalytic reaction, the catalyst can be easily removed from the reaction mixture (advantage of the heterogeneous catalysis). This was achieved through the application of microgels with defined CAT (critical aggregation temperature) properties. After the implementation of the reaction and cooling down of the reaction mixture, aggregated hybrid microgel can be easily removed by decantation. The hybrid microgels loaded with noble metals complexes and nanoparticles show high catalytic activity and can be reused several times. The second part of the work focuses on the synthesis of conductive inks based on water dispersed conductive hybrid microgels. This can be used for the fabrication of smart textiles. In this work it was possible to create continuous connections between hardware components or to create high-flexible electrical circuits for different applications. An approach to use a combination of the microgel flexibility and metal conductivity has significantly reduced the production costs and wearability of the functional textiles. The electrical conductivity of the hybrid microgel films loaded with silver was close to the conductivity of bulk silver. Due to the high mechanical properties, films can be bent for 5000 times without losing conductivity.