Preparing mono-dispersed liquid core PDMS microcapsules from thiol-ene-epoxy-tailored flow-focusing microfluidic devices

An applied dual-cure system based on thiol-ene and thiol-epoxy "click chemistry" reactions was proved to be an extremely effective and easy to use tool for preparing microfluidic chips, thereby allowing for precise control over material properties and providing the possibility of covalently bonding chip wafers. Different thiol-ene-epoxy-based polymer compositions were tested with the help of DSC and ATR FTIR, in order to investigate their physical and chemical properties. Water contact angles were determined, thus verifying the high efficiency and selectivity of the chemical surface modification of compositions in relation to high hydrophilicity and hydrophobicity. An obtained microfluidic device was subsequently used in order to produce PDMS microcapsules of very narrow size distribution and which contained various common liquids, such as water and ethanol, as well as an ionic liquid 2-hydroxyethylammonium formate. A dual-cure system based on thiol-ene and thiol-epoxy "click chemistry" reactions proved to be an effective and easy to use tool for microfluidic chips, which provides control over material properties and enables covalently bonding of chip wafers.