Development of stimulus-responsive materials with improved performance characteristics for application as flow controllers in microfluidic platforms

摘要

This thesis investigates the synthesis and performance of various stimuli-responsive materials with the aim of obtaining a suitable material for flow control in microfluidic platforms. Therefore, at first a literature review is carried out to choose a material for investigation as well as to determine the limitations of current materials so that potential areas where improvements can be made are defined. The materials chosen are mainly based on thermo-responsive polymer N-isopropylacrylamide. Hence, in the beginning the polymerisation of this polymer is investigated in various phosphonium-based ionic liquids to afford novel ionogels with tuneable viscoelastic properties that can serve as robust platforms for incorporation of stimulus- responsive entities. Later these ionogels are demonstrated as a novel and suitable platform for incorporating functionalised magnetic particles to obtain a magneto-responsive, soft ionogel. Photo-responsive gels are obtained by incorporation of spiropyran molecule into the polymer matrix. Improvements to the existing formulations are made by incorporation poly-acid in the polymer chains which allows the material to be actuated without additional chemicals. Moreover, the speed of actuation is improved by engineering a porous microstructure of the gels. Finally, as a future outlook, recently discovered, thermo-responsive poly-ionic liquids are investigated as potential substrates for novel stimulus responsive poly-ionic liquid gels. All these materials have been investigated from the perspective of incorporation into microfluidic devices as soft polymeric valves.