473743 Clickable Janus Particles

Wednesday, November 16, 2016: 8:30 AM
Union Square 23 & 24 (Hilton San Francisco Union Square)
Laura Bradley, Kathleen Stebe and Daeyeon Lee, Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA

The rising interest in the use of particles as solid surfactants in multiphasic systems has been motivated by prospects to increase emulsion stability and facilitate surfactant removal and recycling. While many systems have utilized homogeneous particles to form stable Pickering emulsions, amphiphilic Janus particles offer enhanced attachment energies and the potential to tailor the functionality to specific fluid phases. Current methods for the fabrication of Janus particles in bulk solutions rely on phase separation mechanisms which are highly dependent on the interaction energies between precursors, requiring unique synthesis conditions. In order for Janus particles to be viable solid surfactants on a large scale, it is necessary to develop versatile methods of fabrication that enable the chemical composition to be tailored to specific applications. Inspired by recent advances in click chemistry for particle synthesis, we developed clickable Janus particles containing alkyne pendant groups that can participate in thiol-yne click reactions to transform the chemical functionality and surface charge. The integration of alkyne pendant groups allows us to take advantage of the suite of thiols already commercially available for synthesis of a wide range of functional Janus particles. We demonstrate functionalizing clickable Janus particles to be amphiphilic by introducing either carboxyl, hydroxyl, or amine moieties. Click chemistry not only allows us to tailor the chemical functionality and surface charge of Janus particles, but also enables us to control the extent of functionalization which we show influences the particle morphology and emulsion stability. Furthermore, multi-functional Janus particles can be easily synthesized by performing sequential click reactions. The use of thiol-yne click chemistry to functionalize clickable Janus particles offers a fast-reacting, scalable method to design functional Janus particles for potential use as solid surfactants.

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