(32d) Use of Schizophrenic Diblock-Copolymer-Functionalized Silica Particles As Thermoresponsive Emulsifiers

Temperature responsive emulsions are of particular interest in many industrial applications like enhanced oil recovery and transportation. Most of the literature on thermo-responsive emulsions was focused on the systems that enable the formation of stable emulsions at room temperature, which can subsequently be triggered to destabilize with an increase in temperature. The development of a thermoresponsive system that forms stable emulsions at elevated temperatures, and that subsequently can be induced to phase separate at lower temperatures, has so far been lacking. In this presentation, we highlight the properties of schizophrenic diblock copolymers that can be exploited to create such systems. The diblock copolymer was conjugated to 20 nm silica nanoparticles, which were subsequently demonstrated to stabilize Oil-in-Water emulsions at 65 °C and to induce phase separation upon cooling to 25 °C. The effects of particle concentration, electrolyte concentration, and polymer architecture were investigated, and facile control of emulsion stability was demonstrated for multiple oil types (Langmuir 33, 13326-13331, 2017). Our approach is likely to be broadly adaptable to other schizophrenic diblock copolymers and to find significant utility in applications such as enhanced oil recovery and liquid-phase heterogeneous catalysis, where stable emulsions are desired only at elevated temperatures.